Learning Center

In the United States, municipal drinking water does not come from sewer unless specified by your city's water report and presence of a Reverse Osmosis Water Purification Plant. 

But, the virus that causes COVID-19 has not been detected in drinking water. Conventional water treatment methods that use filtration and disinfection (ammonia and chlorine), such as those in most municipal drinking water systems, should remove or inactivate the virus that causes COVID-19.

The virus that causes COVID-19 has been found in the feces of some patients diagnosed with COVID-19. However, it is unclear whether the virus found in feces may be capable of causing COVID-19. There has not been any confirmed report of the virus spreading from feces to a person. Scientists also do not know how much risk there is that the virus could be spread from the feces of an infected person to another person. However, they think this risk is low based on data from previous outbreaks of diseases caused by related coronaviruses, such as severe acute respiratory syndrome (SARS) and Middle East respiratory syndrome (MERS).

There is no evidence that the Coronavirus that causes COVID-19 can be spread to people through the water in pools, hot tubs, spas, or water play areas. Proper operation and maintenance (including disinfection with chlorine and bromine) of these facilities should inactivate the virus in the water.

While there is ongoing community spread of COVID-19 of the virus that causes COVID-19, it is important for individuals as well as owners and operators of these facilities to take steps to ensure health and safety:

• Everyone should follow local and state guidance that may determine when and how recreational water facilities may operate.
• Individuals should continue to protect themselves and others at recreational water venues both in and out of the water – for example, by practicing social distancing and good hand hygiene.
• In addition to ensuring water safety and quality, owners and operators of community pools, hot tubs, spas, and water play areas should follow the interim guidance for businesses and employers for cleaning and disinfecting their community facilities.

As mentioned in Q#1, the drinking water in the US is not produced by purifying waste water but comes from springs, lakes, rivers, ground water and sometimes RO water bought from an RO plant that purifies seawater. Some US military bases located in deserts, where drinking water is not widely available, recycle and purify sewer water because Reverse Osmosis is built for that very purpose, restoring brackish and sewer into clean, healthy drinking water, so in those cases the answer is: 

 The virus that causes COVID-19 has been found in untreated wastewater. Researchers do not know whether this virus can cause disease if a person is exposed to untreated wastewater or sewerage systems. There is no evidence to date that this has occurred. At this time, the risk of transmission of the virus that causes COVID-19 through properly designed and maintained sewerage systems is thought to be low.

Researchers have analyzed the available information which suggest that standard municipal and individual septic systemexternal iconwastewater treatment practices should inactivate the virus that causes COVID-19. CDC is reviewing information on COVID-19 transmission as it becomes available. Guidance will be updated as new evidence is assessed.

Recently, the virus that causes COVID-19 has been found in untreated wastewater. While data are limited, there is no information to date that anyone has become sick with COVID-19 because of exposure to wastewater.

Standard practices associated with wastewater treatment plant operations should be sufficient to protect wastewater workers from the virus that causes COVID-19. These standard practices can include engineering and administrative controls, hygiene precautions, specific safe work practices, and personal protective equipment (PPE) normally required when handling untreated wastewater. No additional COVID-19–specific protections are recommended for workers involved in wastewater management, including those at wastewater treatment facilities.

In most cases, it is safe to wash your hands with soap and tap water during a Boil Water Advisory. Follow the guidance from your local public health officials. If soap and water are not available, use an alcohol-based hand sanitizer containing at least 60% alcohol.

People with compromised immune systems may want to take special precautions with the water they drink. In healthy individuals, the parasite Cryptosporidium can cause illness; however, for those with weakened immune systems, it can cause severe illness and possibly death. Look for bottled water treatments or alternatives that protect against Cryptosporidium, which include:

• Reverse Osmosis (RO) 
• Distillation
• Filtration with an absolute 1 micron filter (these come as part of every RO System)

Hard water is a common quality of water which contains dissolved compounds of calcium and magnesium and, sometimes, other divalent and trivalent metallic elements. 

 The term hardness was originally applied to waters that were hard to wash in, referring to the soap wasting properties of hard water. Hardness prevents soap from lathering by causing the development of an insoluble curdy precipitate in the water; hardness typically causes the buildup of hardness scale (such as seen in cooking pans). Dissolved calcium and magnesium salts are primarily responsible for most scaling in pipes and water heaters and cause numerous problems in laundry, kitchen, and bath. Hardness is usually expressed in grains per gallon (or ppm) as calcium carbonate equivalent.

The degree of hardness standard as established by the American Society of Agricultural Engineers (S-339) and the Water Quality Association (WQA) is:

Degree of Hardness	Grains per Gallon (gpg)	ppm (or mg/L)
Soft	<1.0	<17.0
Slightly Hard	1.0-3.5	17.1-60
Moderately Hard	3.5-7.0	60-120
Hard	7.0-10.5	120-180
Very Hard	>10.5	>180

Symptoms include:

• Stiff, dingy laundry
• Mineral deposits on dishes and glassware 
• High soap usage & need for fabric softeners 
• Dry, itchy skin and scalp 
• Unmanageable hair 
• Extra work to remove soap curd on bathtubs & shower stalls 
• High energy costs, possibly due to scale build-up in pipes and on appliances
• Scale build up in sinks, tubs, faucets & appliances

Patterns of hardness in the United States are shown on the map of accounting units below. Softest waters were in parts of New England, the South Atlantic-Gulf States, the Pacific Northwest, and Hawaii. Moderately hard waters were common in many rivers of Alaska and Tennessee, in the Great Lakes region, and the Pacific Northwest. Moderately hard waters were common in many rivers of Alaska and Tennessee, the Great Lakes region, and the Pacific Northwest. Hard and very hard waters were found in some streams in most of the regions throughout the country. Hardest waters (greater than 1,000 mg/L) were measured in streams in Texas, New Mexico, Kansas, Arizona, and southern California.

Water treatment can improve hardness issues.

Scale deposits from hardness buildup affects fixtures and appliances found throughout the entire home or business. For this reason, hardness is typically addressed with treatment of water for the whole house or building rather than just at a specific faucet. Hardness minerals can be reduced in water for the whole house to make it “softer” by using one of the following means:

• Chemical softening—lime softening, hot and cold; lime-soda softening

• Membrane separation softening—Nano filtration

• Cation exchange softening—inorganic, carbonaceous, or organic base exchangers
  

If hard water is your problem there are 2 solutions to fix it: POE and POU

Point-of-Entry (POE) 

Solutions Point-of-Entry (POE) devices are whole-house treatment systems mainly designed to reduce contaminants in water intended for showering, washing dishes and clothes, brushing teeth, and flushing toilets.

Ion Exchange  

Ion exchange operations and the choice of resins to use is highly dependent on the water analysis, what has to be removed and to what level it has to be reduced. 

The primary driving force is selectivity. Selectivity is determined by the ionic strength of the charge on the specific ion and the resin type plus this is highly influenced by the other ions in solution that might compete for the reactive sites.  No resin is so highly selective that it is exclusive for a specific contaminant. Since most ion exchange processes are reversible, the ion exchangers can be regenerated (put back into their original form) and used over and over

Cation Exchange Water Softening

Ion exchange water softeners are among the most common ways of softening water. The typical ion exchange system consists of a pressure tank filled with sulfonated, polystyrene beads that are capable of removing hardness ions from water and replacing them with softer ions, such as sodium.

These units are connected to a brine tank that’s filled with salt, which periodically regenerates the resin beads. The unit’s tiny beads attract and hold onto calcium and magnesium ions as water passes through them. When the beads become so saturated they can’t hold any more, the unit rinses them with salt, which scrubs off the mineral deposits and gets them ready to absorb hardness ions again.

If you own this type of water softener, you can set it to regenerate at preset times. More sophisticated units can base their regeneration on your actual water use. Systems that measure water use and regenerate accordingly, called demand initiated regeneration (DIR), may be more efficient because they only regenerate as needed. Systems that automatically regenerate on set time intervals, called time clocks, simplify the process. However, these units sometimes regenerate more often than necessary, wasting salt, or they leave users with hard water when water demand is higher than normal.

Filtration Systems

Although water softeners get rid of some heavy metals along with hardness, water filtration systems are the best way to remove organic and inorganic materials (such as microbiological contaminants) and particulates (such as sand, rust and silt). Water filters remove these impurities with a fine physical barrier, chemicals, or some other method to help clean water and make it suitable for drinking or other uses.

While specialty media and membranes are available, activated carbon is a widely used filtration substance. Activated carbon targets various volatile organic compounds, such as benzene, trichloroethylene, and various pesticides and petroleum related compounds. Sediment and tank filtration systems removes contaminants as water enters the home. Large inline filtration systems are installed where water enters the home plumbing system.

Electrochemical Water Treatment Systems

Electrochemical water treatment systems utilize electricity to induce the removal of dissolved contaminants in the water. Positively charged contaminants such as calcium, magnesium, sodium, lead and uranium, are called cations. Negatively charged contaminants such as chlorides, nitrates, nitrites, sulfates and fluorides, are called anions. The introduction of a negatively charged electrode, or cathode, into the water will cause positively charged cations to move towards it. 

Electrochemical water treatment systems take advantage of this property by combining the electrode with ion exchange membranes. Basically anything that is ionized when dissolved in water will be reduced.  A typical target for the product water would be <5 grains per gallon of hardness and <150 ppm of total dissolved solids, but they are not practical if your aim is to produce soft water with <1 grain of hardness.

Point-of-Use (POU) Solutions

Point-of-Use (POU) devices treat water at the point of consumption. The technology provides the final barrier to the contaminants of concern before the water is consumed or used. Some technologies that are commonly applied at the point of use, but may also be applied at the point of entry (POE), include the following:

• Activated Carbon 
  
• Reverse Osmosis 
  
• Ultraviolet (UV) Technologies 
  
• Distillation 
  

Activated Carbon 

Activated carbon is a widely used filtration substance that targets various volatile organic compounds, such as benzene, trichloroethylene, and various pesticides and petroleum related compounds. Maintenance is as simple as swapping out a cartridge once or twice a year. Activated carbon may be granular or in a solid block. Some carbon block filters can have greater filtration capabilities that can remove lead, asbestos, and some microbes out of the water. Activated carbon is may be used in gravity devices (such as countertop pitchers) and inline filters.

Reverse Osmosis

Reverse osmosis (RO) systems force water, under pressure, into a module that contains a semipermeable membrane and a number of other filtration steps. A typical RO system has a prefilter designed to capture larger particles, chlorine, and other substances; a semipermeable membrane that captures more contaminants; an activated carbon filter that removes residual taste, odor, and some organic contaminants; and a storage tank to hold the treated water for use.

Whole-house (point-of-entry) RO systems exist, but they are more commonly installed near the point-of-use, such as on a countertop or under a sink. They’re great for treating water for cooking and drinking. Typically people choose to install RO-treated faucets in the most popular areas of the home such as kitchens and bathrooms, as opposed to installing it for every drinking tap.

Just like any other kind of filter technology, RO systems require regular maintenance. That includes periodically replacing the unit’s prefilters, postfilters, and membrane modules. How often you need to replace these depends on the quality of your system and its components. 

Ultraviolet (UV) Light

Disinfecting of water with ultraviolet (UV) light has long been popular for commercial use, and is becoming more common in homes. UV systems expose water to light at just the right wavelength for killing microbes. It’s a way to kill bacteria, viruses, fungi, protozoans and cysts that may be present in the water. The effectiveness of the system depends on the strength and intensity of the light, the amount of time the light shines through the water, and, of course, the quantity of particles in the water in the first place. The light source must be kept clean and the UV lamp replaced periodically.

UV light treatment can’t remove gases, heavy metals and particulates. For this reason, higher-end systems may include additional filtration such as activated carbon. If so, that means you’ll need to occasionally clean or replace those filters or perform other maintenance.    

Distillation

Distillation is one of the oldest water-purification methods around. It can effectively remove minerals, most chemicals and many bad tastes from tap water. In a distillation system, the water is heated until it reaches its boiling point and begins to vaporize. The vaporized water is then fed into a condenser that cools the steam and converts the water back to liquid form. A vent to discharge gases is a common feature, and these units may also include an activated carbon filter to pull out even more contaminants. Most home distillers produce only small amounts of treated water daily. They require periodic cleaning and descaling to remove mineral buildup.

Stains on Plumbing Fixtures

What causes discoloration on sinks, tubs, and toilets?

If the stains or water are blue-green in color, then most likely, corrosion of copper is occurring within the household plumbing. Stains that are various shades of yellow, tan, brown, black, orange, or red can indicate the presence of metals other than copper.

Two other metals that are typically to blame for staining are iron and manganese. While these minerals serve as essential nutrients for your body, they aren’t so kind to plumbing fixtures, appliances and even clothing. Reddish and yellow-tan discoloration is often caused by iron, while black or dark brown discoloration points to manganese. Due to their similarities and their frequent occurrence in tandem, iron and manganese are generally treated in much the same way.

Discoloration usually results from the exposure of these metals to oxygen, known as oxidation. In your plumbing, water often has limited exposure to oxygen, keeping any soluble (ferrous) iron or manganese in solution. Once these metals come out of a faucet and are exposed to the air, oxidation occurs and chemical reactions may cause them to form a substance that creates visible staining.

Staining may result from water with very low concentrations of these metals: 0.3 parts per million (ppm) of iron or 0.05 ppm of manganese. This is why water that leaves stains on plumbing fixtures may appear clear when coming out of the tap.

Some specific kinds of bacteria, which can cause discoloration, thrive in iron- and manganese-rich water. While these bacteria may not be harmful to the human body, they can clog pipes and affect flow rates in a home's plumbing and appliances.

Water treatment can address staining issues.

Stains resulting from metals, tannins or any other contaminant will affect fixtures and appliances found throughout the entire home or business. For this reason, contaminants causing stains are typically addressed with water treatment for the whole house or building rather than just at a specific faucet. Contaminants that stain can be reduced in water by using one of the following means:

• Anion Exchange

• Activated Carbon

• Filtration

• Chlorination

• Reverse Osmosis

• Distillation

• Ozonation

Point-of-Entry (POE) Solutions

Point-of-Entry (POE) devices are whole-house treatment systems mainly designed to reduce contaminants in water intended for showering, washing dishes and clothes, brushing teeth, and flushing toilets.

Ion Exchange  

Ion exchange operations and the choice of resins to use is highly dependent on the water analysis, what has to be removed and to what level it has to be reduced.  

The primary driving force is selectivity. 

Selectivity is determined by the ionic strength of the charge on the specific ion and the resin type plus this is highly influenced by the other ions in solution that might compete for the reactive sites.  No resin is so highly selective that it is exclusive for a specific contaminant. Since most ion exchange processes are reversible, the ion exchangers can be regenerated (put back into their original form) and used over and over.

Cation Exchange Water Softening

Ion exchange water softeners are among the most common ways of softening water. The typical ion exchange system consists of a pressure tank filled with sulfonated, polystyrene beads that are capable of removing hardness ions from water and replacing them with softer ions, such as sodium.

These units are connected to a brine tank that’s filled with salt, which periodically regenerates the resin beads. The unit’s tiny beads attract and hold onto calcium and magnesium ions as water passes through them. When the beads become so saturated they can’t hold any more, the unit rinses them with salt, which scrubs off the mineral deposits and gets them ready to absorb hardness ions again.

If you own this type of water softener, you can set it to regenerate at preset times. More sophisticated units can base their regeneration on your actual water use. Systems that measure water use and regenerate accordingly, called demand initiated regeneration (DIR), may be more efficient because they only regenerate as needed. Systems that automatically regenerate on set time intervals, called time clocks, simplify the process. However, these units sometimes regenerate more often than necessary, wasting salt, or they leave users with hard water when water demand is higher than normal.

Filtration Systems

Although water softeners get rid of some heavy metals along with hardness, water filtration systems are the best way to remove organic and inorganic materials (such as microbiological contaminants) and particulates (such as sand, rust and silt). Water filters remove these impurities with a fine physical barrier, chemicals, or some other method to help clean water and make it suitable for drinking or other uses.

While specialty media and membranes are available, activated carbon is a widely used filtration substance. Activated carbon targets various volatile organic compounds, such as benzene, trichloroethylene, and various pesticides and petroleum related compounds. Sediment and tank filtration systems removes contaminants as water enters the home. Large inline filtration systems are installed where water enters the home plumbing system.

Electrochemical Water Treatment Systems

Electrochemical water treatment systems utilize electricity to induce the removal of dissolved contaminants in the water. Positively charged contaminants such as calcium, magnesium, sodium, lead and uranium, are called cations. Negatively charged contaminants such as chlorides, nitrates, nitrites, sulfates and fluorides, are called anions. The introduction of a negatively charged electrode, or cathode, into the water will cause positively charged cations to move towards it. 

Electrochemical water treatment systems take advantage of this property by combining the electrode with ion exchange membranes. Basically anything that is ionized when dissolved in water will be reduced.  A typical target for the product water would be <5 grains per gallon of hardness and <150 ppm of total dissolved solids, but they are not practical if your aim is to produce soft water with <1 grain of hardness.

Point-of-Use (POU) Solutions

Point-of-Use (POU) devices treat water at the point of consumption. The technology provides the final barrier to the contaminants of concern before the water is consumed or used. Some technologies that are commonly applied at the point of use, but may also be applied at the point of entry (POE), include the following:

• Activated Carbon 
  
• Reverse Osmosis 
  
• Ultraviolet (UV) Technologies 
  
• Distillation 
  

Activated Carbon 

Activated carbon is a widely used filtration substance that targets various volatile organic compounds, such as benzene, trichloroethylene, and various pesticides and petroleum related compounds. Maintenance is as simple as swapping out a cartridge once or twice a year. Activated carbon may be granular or in a solid block. Some carbon block filters can have greater filtration capabilities that can remove lead, asbestos, and some microbes out of the water. Activated carbon is may be used in gravity devices (such as countertop pitchers) and inline filters.

Reverse Osmosis

Reverse osmosis (RO) systems force water, under pressure, into a module that contains a semipermeable membrane and a number of other filtration steps. A typical RO system has a prefilter designed to capture larger particles, chlorine, and other substances; a semipermeable membrane that captures more contaminants; an activated carbon filter that removes residual taste, odor, and some organic contaminants; and a storage tank to hold the treated water for use.

Whole-house (point-of-entry) RO systems exist, but they are more commonly installed near the point-of-use, such as on a countertop or under a sink. They’re great for treating water for cooking and drinking. Typically people choose to install RO-treated faucets in the most popular areas of the home such as kitchens and bathrooms, as opposed to installing it for every drinking tap.

Just like any other kind of filter technology, RO systems require regular maintenance. That includes periodically replacing the unit’s prefilters, postfilters, and membrane modules. How often you need to replace these depends on the quality of your system and its components. 

Ultraviolet (UV) Light

Disinfecting of water with ultraviolet (UV) light has long been popular for commercial use, and is becoming more common in homes. UV systems expose water to light at just the right wavelength for killing microbes. It’s a way to kill bacteria, viruses, fungi, protozoans and cysts that may be present in the water. The effectiveness of the system depends on the strength and intensity of the light, the amount of time the light shines through the water, and, of course, the quantity of particles in the water in the first place. The light source must be kept clean and the UV lamp replaced periodically.

UV light treatment can’t remove gases, heavy metals and particulates. For this reason, higher-end systems may include additional filtration such as activated carbon. If so, that means you’ll need to occasionally clean or replace those filters or perform other maintenance.    

Distillation

Distillation is one of the oldest water-purification methods around. It can effectively remove minerals, most chemicals and many bad tastes from tap water. In a distillation system, the water is heated until it reaches its boiling point and begins to vaporize. The vaporized water is then fed into a condenser that cools the steam and converts the water back to liquid form. A vent to discharge gases is a common feature, and these units may also include an activated carbon filter to pull out even more contaminants. Most home distillers produce only small amounts of treated water daily. They require periodic cleaning and descaling to remove mineral buildup.

Taste & Odor Issues

While taste issues are only noticed at the faucet(s) where water is used for drinking, bad smelling water can be noticeable any place in or around a home or office where water is used.

Depending on the extent of faucets affected, a choice can be made whether water treatment for the whole building or just at a specific faucet is best suited for your needs.

Water treatment can improve taste and odor issues.

Contaminants that cause taste and odor issues can be reduced in water by using one or multiple options listed below:

• Activated Carbon
  
• Reverse Osmosis
  
• Air Stripping
  
• Oxidation/Filtration
  
• Disinfection/Filtration
  
• pH adjustments higher or lower
  
• Anion Exchange
  
• Distillation
  
• Electrodialysis
  
• Deionization
  
• Cation Exchange
  
• Ultrafiltration
  
• Filtration
  

Point-of-Entry (POE) Solutions

Point-of-Entry (POE) devices are whole-house treatment systems mainly designed to reduce contaminants in water intended for showering, washing dishes and clothes, brushing teeth, and flushing toilets.

Ion Exchange  

Ion exchange operations and the choice of resins to use is highly dependent on the water analysis, what has to be removed and to what level it has to be reduced.  

The primary driving force is selectivity. 

Selectivity is determined by the ionic strength of the charge on the specific ion and the resin type plus this is highly influenced by the other ions in solution that might compete for the reactive sites.  No resin is so highly selective that it is exclusive for a specific contaminant. Since most ion exchange processes are reversible, the ion exchangers can be regenerated (put back into their original form) and used over and over.

Cation Exchange Water Softening

Ion exchange water softeners are among the most common ways of softening water. The typical ion exchange system consists of a pressure tank filled with sulfonated, polystyrene beads that are capable of removing hardness ions from water and replacing them with softer ions, such as sodium.

These units are connected to a brine tank that’s filled with salt, which periodically regenerates the resin beads. The unit’s tiny beads attract and hold onto calcium and magnesium ions as water passes through them. When the beads become so saturated they can’t hold any more, the unit rinses them with salt, which scrubs off the mineral deposits and gets them ready to absorb hardness ions again.

If you own this type of water softener, you can set it to regenerate at preset times. More sophisticated units can base their regeneration on your actual water use. Systems that measure water use and regenerate accordingly, called demand initiated regeneration (DIR), may be more efficient because they only regenerate as needed. Systems that automatically regenerate on set time intervals, called time clocks, simplify the process. However, these units sometimes regenerate more often than necessary, wasting salt, or they leave users with hard water when water demand is higher than normal.

Filtration Systems

Although water softeners get rid of some heavy metals along with hardness, water filtration systems are the best way to remove organic and inorganic materials (such as microbiological contaminants) and particulates (such as sand, rust and silt). Water filters remove these impurities with a fine physical barrier, chemicals, or some other method to help clean water and make it suitable for drinking or other uses.

While specialty media and membranes are available, activated carbon is a widely used filtration substance. Activated carbon targets various volatile organic compounds, such as benzene, trichloroethylene, and various pesticides and petroleum related compounds. Sediment and tank filtration systems removes contaminants as water enters the home. Large inline filtration systems are installed where water enters the home plumbing system.

Electrochemical Water Treatment Systems

Electrochemical water treatment systems utilize electricity to induce the removal of dissolved contaminants in the water. Positively charged contaminants such as calcium, magnesium, sodium, lead and uranium, are called cations. Negatively charged contaminants such as chlorides, nitrates, nitrites, sulfates and fluorides, are called anions. The introduction of a negatively charged electrode, or cathode, into the water will cause positively charged cations to move towards it. 

Electrochemical water treatment systems take advantage of this property by combining the electrode with ion exchange membranes. Basically anything that is ionized when dissolved in water will be reduced.  A typical target for the product water would be <5 grains per gallon of hardness and <150 ppm of total dissolved solids, but they are not practical if your aim is to produce soft water with <1 grain of hardness.

Point-of-Use (POU) Solutions

Point-of-Use (POU) devices treat water at the point of consumption. The technology provides the final barrier to the contaminants of concern before the water is consumed or used. Some technologies that are commonly applied at the point of use, but may also be applied at the point of entry (POE), include the following:

• Activated Carbon 
  
• Reverse Osmosis 
  
• Ultraviolet (UV) Technologies 
  
• Distillation 
  

Activated Carbon 

Activated carbon is a widely used filtration substance that targets various volatile organic compounds, such as benzene, trichloroethylene, and various pesticides and petroleum related compounds. Maintenance is as simple as swapping out a cartridge once or twice a year. Activated carbon may be granular or in a solid block. Some carbon block filters can have greater filtration capabilities that can remove lead, asbestos, and some microbes out of the water. Activated carbon is may be used in gravity devices (such as countertop pitchers) and inline filters.

Reverse Osmosis

Reverse osmosis (RO) systems force water, under pressure, into a module that contains a semipermeable membrane and a number of other filtration steps. A typical RO system has a prefilter designed to capture larger particles, chlorine, and other substances; a semipermeable membrane that captures more contaminants; an activated carbon filter that removes residual taste, odor, and some organic contaminants; and a storage tank to hold the treated water for use.

Whole-house (point-of-entry) RO systems exist, but they are more commonly installed near the point-of-use, such as on a countertop or under a sink. They’re great for treating water for cooking and drinking. Typically people choose to install RO-treated faucets in the most popular areas of the home such as kitchens and bathrooms, as opposed to installing it for every drinking tap.

Just like any other kind of filter technology, RO systems require regular maintenance. That includes periodically replacing the unit’s prefilters, postfilters, and membrane modules. How often you need to replace these depends on the quality of your system and its components. 

Ultraviolet (UV) Light

Disinfecting of water with ultraviolet (UV) light has long been popular for commercial use, and is becoming more common in homes. UV systems expose water to light at just the right wavelength for killing microbes. It’s a way to kill bacteria, viruses, fungi, protozoans and cysts that may be present in the water. The effectiveness of the system depends on the strength and intensity of the light, the amount of time the light shines through the water, and, of course, the quantity of particles in the water in the first place. The light source must be kept clean and the UV lamp replaced periodically.

UV light treatment can’t remove gases, heavy metals and particulates. For this reason, higher-end systems may include additional filtration such as activated carbon. If so, that means you’ll need to occasionally clean or replace those filters or perform other maintenance.    

Distillation

Distillation is one of the oldest water-purification methods around. It can effectively remove minerals, most chemicals and many bad tastes from tap water. In a distillation system, the water is heated until it reaches its boiling point and begins to vaporize. The vaporized water is then fed into a condenser that cools the steam and converts the water back to liquid form. A vent to discharge gases is a common feature, and these units may also include an activated carbon filter to pull out even more contaminants. Most home distillers produce only small amounts of treated water daily. They require periodic cleaning and descaling to remove mineral buildup.

Cloudiness & Discoloration Issues

It isn’t just fixtures and appliances that can be discolored and stained. Discoloration of water is another sign of impurities.

Water treatment can improve cloudiness and discoloration issues.

Turbidity refers to the amount of small particles of solid matter suspended in water as measured by the amount of scattering and absorption of light rays caused by the particles. Turbidity blocks light rays and makes the water opaque. Turbidity is measured in nephelometric turbidity units (NTU). Potable water should not exceed 0.5 NTU. Turbidity cannot be directly equated to suspended solids because white particles reflect more light than dark-colored particles and many small particles will reflect more light than an equivalent large particle.

In most cases, water cloudiness and discoloration is a noticeable issue in bath water and at the faucet(s) where water is used for drinking. To clear up water used for bathing, treating water for the whole house or building is necessary. If cloudiness or discoloration of water is only an issue for drinking water, then it is best to treat water at the faucet where it is used. Contaminants that cause cloudiness or discoloration of the water can be reduced by using POU and POE filtration systems.

Point-of-Entry (POE) Solutions

Point-of-Entry (POE) devices are whole-house treatment systems mainly designed to reduce contaminants in water intended for showering, washing dishes and clothes, brushing teeth, and flushing toilets.

Ion Exchange  

Ion exchange operations and the choice of resins to use is highly dependent on the water analysis, what has to be removed and to what level it has to be reduced.  

The primary driving force is selectivity. 

Selectivity is determined by the ionic strength of the charge on the specific ion and the resin type plus this is highly influenced by the other ions in solution that might compete for the reactive sites.  No resin is so highly selective that it is exclusive for a specific contaminant. Since most ion exchange processes are reversible, the ion exchangers can be regenerated (put back into their original form) and used over and over.

Cation Exchange Water Softening

Ion exchange water softeners are among the most common ways of softening water. The typical ion exchange system consists of a pressure tank filled with sulfonated, polystyrene beads that are capable of removing hardness ions from water and replacing them with softer ions, such as sodium.

These units are connected to a brine tank that’s filled with salt, which periodically regenerates the resin beads. The unit’s tiny beads attract and hold onto calcium and magnesium ions as water passes through them. When the beads become so saturated they can’t hold any more, the unit rinses them with salt, which scrubs off the mineral deposits and gets them ready to absorb hardness ions again.

If you own this type of water softener, you can set it to regenerate at preset times. More sophisticated units can base their regeneration on your actual water use. Systems that measure water use and regenerate accordingly, called demand initiated regeneration (DIR), may be more efficient because they only regenerate as needed. Systems that automatically regenerate on set time intervals, called time clocks, simplify the process. However, these units sometimes regenerate more often than necessary, wasting salt, or they leave users with hard water when water demand is higher than normal.

Filtration Systems

Although water softeners get rid of some heavy metals along with hardness, water filtration systems are the best way to remove organic and inorganic materials (such as microbiological contaminants) and particulates (such as sand, rust and silt). Water filters remove these impurities with a fine physical barrier, chemicals, or some other method to help clean water and make it suitable for drinking or other uses.

While specialty media and membranes are available, activated carbon is a widely used filtration substance. Activated carbon targets various volatile organic compounds, such as benzene, trichloroethylene, and various pesticides and petroleum related compounds. Sediment and tank filtration systems removes contaminants as water enters the home. Large inline filtration systems are installed where water enters the home plumbing system.

Electrochemical Water Treatment Systems

Electrochemical water treatment systems utilize electricity to induce the removal of dissolved contaminants in the water. Positively charged contaminants such as calcium, magnesium, sodium, lead and uranium, are called cations. Negatively charged contaminants such as chlorides, nitrates, nitrites, sulfates and fluorides, are called anions. The introduction of a negatively charged electrode, or cathode, into the water will cause positively charged cations to move towards it. 

Electrochemical water treatment systems take advantage of this property by combining the electrode with ion exchange membranes. Basically anything that is ionized when dissolved in water will be reduced.  A typical target for the product water would be <5 grains per gallon of hardness and <150 ppm of total dissolved solids, but they are not practical if your aim is to produce soft water with <1 grain of hardness.

Point-of-Use (POU) Solutions

Point-of-Use (POU) devices treat water at the point of consumption. The technology provides the final barrier to the contaminants of concern before the water is consumed or used. Some technologies that are commonly applied at the point of use, but may also be applied at the point of entry (POE), include the following:

• Activated Carbon 
  
• Reverse Osmosis 
  
• Ultraviolet (UV) Technologies 
  
• Distillation 
  

Activated Carbon 

Activated carbon is a widely used filtration substance that targets various volatile organic compounds, such as benzene, trichloroethylene, and various pesticides and petroleum related compounds. Maintenance is as simple as swapping out a cartridge once or twice a year. Activated carbon may be granular or in a solid block. Some carbon block filters can have greater filtration capabilities that can remove lead, asbestos, and some microbes out of the water. Activated carbon is may be used in gravity devices (such as countertop pitchers) and inline filters.

Reverse Osmosis

Reverse osmosis (RO) systems force water, under pressure, into a module that contains a semipermeable membrane and a number of other filtration steps. A typical RO system has a prefilter designed to capture larger particles, chlorine, and other substances; a semipermeable membrane that captures more contaminants; an activated carbon filter that removes residual taste, odor, and some organic contaminants; and a storage tank to hold the treated water for use.

Whole-house (point-of-entry) RO systems exist, but they are more commonly installed near the point-of-use, such as on a countertop or under a sink. They’re great for treating water for cooking and drinking. Typically people choose to install RO-treated faucets in the most popular areas of the home such as kitchens and bathrooms, as opposed to installing it for every drinking tap.

Just like any other kind of filter technology, RO systems require regular maintenance. That includes periodically replacing the unit’s prefilters, postfilters, and membrane modules. How often you need to replace these depends on the quality of your system and its components. 

Ultraviolet (UV) Light

Disinfecting of water with ultraviolet (UV) light has long been popular for commercial use, and is becoming more common in homes. UV systems expose water to light at just the right wavelength for killing microbes. It’s a way to kill bacteria, viruses, fungi, protozoans and cysts that may be present in the water. The effectiveness of the system depends on the strength and intensity of the light, the amount of time the light shines through the water, and, of course, the quantity of particles in the water in the first place. The light source must be kept clean and the UV lamp replaced periodically.

UV light treatment can’t remove gases, heavy metals and particulates. For this reason, higher-end systems may include additional filtration such as activated carbon. If so, that means you’ll need to occasionally clean or replace those filters or perform other maintenance.    

Distillation

Distillation is one of the oldest water-purification methods around. It can effectively remove minerals, most chemicals and many bad tastes from tap water. In a distillation system, the water is heated until it reaches its boiling point and begins to vaporize. The vaporized water is then fed into a condenser that cools the steam and converts the water back to liquid form. A vent to discharge gases is a common feature, and these units may also include an activated carbon filter to pull out even more contaminants. Most home distillers produce only small amounts of treated water daily. They require periodic cleaning and descaling to remove mineral buildup.

Corrosion Issues

The corrosion of pipes and plumbing fixtures can cause a bevy of problems with your water. Corrosion is the gradual decomposition or destruction of a material by oxidation or chemical actions, often due to an electrochemical reaction. Corrosion starts at the surface or a material and moves inward. Corrosion of iron or steel is commonly called rusting.

A number of factors will accelerate corrosion, including:

• Acidity (low pH)
• High mineral concentrations 
• Stray current electrolysis
• Galvanic corrosion caused by dissimilar metals
• Dissolved oxygen content
• Water temperatures

Water treatment can improve corrosion issues.

The following types of water treatment solutions are recommended:

• Reverse Osmosis
• Water Softeners
• Limestone chip filters
• Soda ash feeds
• Phosphate solution feeds
• Silicate solution feeds
• Oxygen scavengers
• Coatings

• Insulating unions

• Arsenic is naturally present at high levels in the groundwater of a number of countries.
  
• Arsenic is highly toxic in its inorganic form. Contaminated water used for drinking, food preparation and irrigation of food crops poses the greatest threat to public health from arsenic.
  
• Long-term exposure to arsenic from drinking-water and food can cause cancer and skin lesions. It has also been associated with cardiovascular disease and diabetes. In utero and early childhood exposure has been linked to negative impacts on cognitive development and increased deaths in young adults.
  
• The most important action in affected communities is the prevention of further exposure to arsenic by provision of a safe water supply.

Arsenic is one of a handful of chemicals that have been classified as a known human carcinogen. 

Exposure can lead to cancers, development effects, pulmonary disease, or cardiovascular disease.
In 2015, there were 1,537 violations (1,135 of them health-based) at community water systems serving 1,842,594 people (358,323 health-based).
Formal enforcement was taken in 28.9 percent of cases (37.1 percent of health-based cases). 

Less than one in eight of the violations (and about one in twenty health-based violations) returned to compliance within the calendar year.

Sources of exposure

Arsenic is a natural component of the earth’s crust and is widely distributed throughout the environment in the air, water and land. It is highly toxic in its inorganic form.

People are exposed to elevated levels of inorganic arsenic through drinking contaminated water, using contaminated water in food preparation and irrigation of food crops, industrial processes, eating contaminated food and smoking tobacco.

Long-term exposure to inorganic arsenic, mainly through drinking-water and food, can lead to chronic arsenic poisoning. Skin lesions and skin cancer are the most characteristic effects.

Arsenic is a metalloid, which has the properties of both a metal and a nonmetal. It can be found in both organic and inorganic form. 

It is typically found as an inorganic substance in the environment, combined with other elements such as oxygen, chlorine, and sulfur. Arsenic compounds have no smell and no distinctive taste. You cannot typically detect its presence in water without testing. Arsenic can be released from both natural and human activity. 

Inorganic arsenic is used in wood preservative treatments, and before this decade it was widely used as a pesticide. Because arsenic occurs naturally with many minerals, it is commonly exposed by mining operations, particularly from the smelting process, and can get into water as a result. Arsenic may enter drinking water sources from wind-blown dust or from runoff and leaching. Arsenic may also be released into the atmosphere from coal-fired power plants and incinerators. Arsenic in these emissions can then travel through the air and end up in surface water or groundwater by dissolving in rain or snow.

Drinking-water and food

The greatest threat to public health from arsenic originates from contaminated groundwater. Inorganic arsenic is naturally present at high levels in the groundwater of a number of countries, including Argentina, Bangladesh, Chile, China, India, Mexico, and the United States of America. Drinking-water, crops irrigated with contaminated water and food prepared with contaminated water are the sources of exposure.

Fish, shellfish, meat, poultry, dairy products and cereals can also be dietary sources of arsenic, although exposure from these foods is generally much lower compared to exposure through contaminated groundwater. In seafood, arsenic is mainly found in its less toxic organic form.

Widespread, high concentrations of arsenic have been found contaminating the groundwater in parts of the West, Southwest, Midwest, parts of Texas, and Northeast.

With long-term exposure, arsenic is a known human carcinogen and is reasonably anticipated to cause lung and bladder cancer, as well as cancer of the skin, kidney, nasal passages, liver, and prostate. Long-term ingestion of inorganic arsenic may also cause developmental effects, neurotoxicity, pulmonary disease, and cardiovascular disease.

Pigmentation changes in the skin and thickening of the skin may also occur with long-term exposure to high levels of inorganic arsenic. Immediate effects of acute (high level) arsenic poisoning include vomiting, abdominal pain, and diarrhea. This may be followed by numbness and tingling of the extremities, partial paralysis, blindness, and even death in extreme instances. 

However, acute, extremely high-concentration arsenic poisoning from public water system drinking water in the United States has not been recently reported; lower-level contamination linked to cancer and other effects is considered the major health concern in the United States. 

Inorganic arsenic is a confirmed carcinogen and is the most significant chemical contaminant in drinking-water globally. Arsenic can also occur in an organic form. Inorganic arsenic compounds (such as those found in water) are highly toxic while organic arsenic compounds (such as those found in seafood) are less harmful to health.

Acute Effects

The immediate symptoms of acute arsenic poisoning include vomiting, abdominal pain and diarrhoea. These are followed by numbness and tingling of the extremities, muscle cramping and death, in extreme cases.

Long-Term Effects

The first symptoms of long-term exposure to high levels of inorganic arsenic (for example, through drinking-water and food) are usually observed in the skin, and include pigmentation changes, skin lesions and hard patches on the palms and soles of the feet (hyperkeratosis). These occur after a minimum exposure of approximately five years and may be a precursor to skin cancer.

In addition to skin cancer, long-term exposure to arsenic may also cause cancers of the bladder and lungs. The International Agency for Research on Cancer (IARC) has classified arsenic and arsenic compounds as carcinogenic to humans, and has also stated that arsenic in drinking-water is carcinogenic to humans.

Other adverse health effects that may be associated with long-term ingestion of inorganic arsenic include developmental effects, diabetes, pulmonary disease, and cardiovascular disease. Arsenic-induced myocardial infarction, in particular, can be a significant cause of excess mortality. In China (Province of Taiwan), arsenic exposure has been linked to “Blackfoot disease”, which is a severe disease of blood vessels leading to gangrene. This disease has not been observed in other parts of the world however, and it is possible that malnutrition contributes to its development.

Arsenic is also associated with adverse pregnancy outcomes and infant mortality, with impacts on child health (1), and exposure in utero and in early childhood has been linked to increases in mortality in young adults due to multiple cancers, lung disease, heart attacks, and kidney failure (2). Numerous studies have demonstrated negative impacts of arsenic exposure on cognitive development, intelligence, and memory (3).

Magnitude Of The Problem

Arsenic contamination of groundwater is widespread and there are a number of regions where arsenic contamination of drinking-water is significant. It is now recognized that at least 140 million people in 50 countries have been drinking water containing arsenic at levels above the WHO provisional guideline value of 10 μg/L (4).

Arsenic in Bangladesh has attracted much attention since recognition in the 1990s of its wide occurrence in well-water in that country. Since this time, significant progress has since been made and the number of people exposed to arsenic exceeding the Bangladesh drinking-water quality standard has decreased by approximately 40%. Despite these efforts, it was estimated that in 2012 about 19 million and 39 million people in Bangladesh were still exposed to arsenic concentrations above the national standard of 50 μg/L and the WHO provisional guideline value of 10 μg/L respectively (5). In a highly affected area of Bangladesh, 21.4% of all deaths in the area were attributed to arsenic levels above 10 μg/L in drinking-water (6). A similar dose-response function has been found in other parts of Bangladesh, and these these results have been combined with national survey data to estimate an annual death toll of nearly 43 000 (7). The US National Research Council has noted that as many as 1 in 100 additional cancer deaths could be expected from a lifetime exposure to drinking-water containing 50 μg/L (8).

The symptoms and signs caused by long-term elevated exposure to inorganic arsenic differ between individuals, population groups and geographical areas. Thus, there is no universal definition of the disease caused by arsenic. This complicates the assessment of the burden on health of arsenic.

Similarly, there is no method to distinguish cases of cancer caused by arsenic from cancers induced by other factors. As a result, there is no reliable estimate of the magnitude of the problem worldwide.

In 2010, the Joint FAO/WHO Expert Committee on Food Additives (JECFA) re-evaluated the effects of arsenic on human health, taking new data into account. JECFA concluded that for certain regions of the world where concentrations of inorganic arsenic in drinking-water exceed 50–100 μg/L, there is some evidence of adverse effects. In other areas, where arsenic concentrations in water are elevated (10–50 μg/L), JECFA concluded that while there is a possibility of adverse effects, these would be at a low incidence that would be difficult to detect in epidemiological studies.

Arsenic is regulated as one of the Inorganic contaminants covered by the Safe Drinking Water Act. 

Currently, the U.S. Environmental Protection Agency (EPA) uses a maximum contaminant level (MCL) of 10 parts per billion (ppb) for arsenic. 

In 1942, the EPA set an interim MCL for arsenic in drinking water of 50 ppb as part of the National Interim Primary Drinking Water Standards. In 1988, the agency conducted a risk assessment for arsenic in drinking water, finding adequate evidence to demonstrate that inorganic arsenic is a human carcinogen by the oral route. 

In the 1996 amendments to the Safe Drinking Water Act (SDWA), Congress instructed the EPA to propose a new arsenic standard. Accordingly, the EPA requested that the National Research Council (NRC), an arm of the National Academy of Sciences, conduct an independent review of arsenic in drinking water. The resulting 1999 report, Arsenic in Drinking Water, concluded that “the current EPA MCL for arsenic in drinking water of 50 μg/L [ppb] does not achieve EPA’s goal for public-health protection and, therefore, requires downward revision as promptly as possible.” 

The EPA proposed a new MCL of 5 ppb, but public health advocates pressed for a more protective standard of 3 ppb. Instead, in response to industry and political pressure, the agency issued a weakened final MCL in January 2001, setting it at 10 ppb.  Even then, when President George W. Bush took office in 2001, he suspended the final rule. An NRDC lawsuit challenging the suspension, a widespread public outcry, and another National Academy of Sciences study issued in September 2001 finding that the EPA had likely substantially underestimated the cancer risks, successfully pushed the agency to ratify the final rule issued earlier that year that had set the MCL at 10 ppb. 

Under the Standardized Monitoring Framework for inorganic chemical contaminants, such as arsenic, groundwater systems are required to sample for arsenic once every three years. Surface water systems must monitor for arsenic once a year. The final Arsenic Rule allows states to issue waivers for arsenic monitoring. After a water system receives a waiver, it must take at least one sample during each nine-year waiver period. If a system’s sample exceeds the MCL, then the system must collect samples quarterly until the system is consistently below the MCL.

Arsenic is used industrially as an alloying agent, as well as in the processing of glass, pigments, textiles, paper, metal adhesives, wood preservatives and ammunition. Arsenic is also used in the hide tanning process and, to a limited extent, in pesticides, feed additives and pharmaceuticals.

People who smoke tobacco can also be exposed to the natural inorganic arsenic content of tobacco because tobacco plants can take up arsenic naturally present in the soil. Also, in the past, the potential for elevated arsenic exposure was much greater when tobacco plants used to be treated with lead arsenate insecticide.

Prevention and control

• Substitute high-arsenic sources, such as groundwater, with low-arsenic, microbiologically safe sources such as rain water and treated surface water. Low-arsenic water can be used for drinking, cooking and irrigation purposes, whereas high-arsenic water can be used for other purposes such as bathing and washing clothes.
  
  
• Discriminate between high-arsenic and low-arsenic sources. For example, test water for arsenic levels and paint tube wells or hand pumps different colours. This can be an effective and low-cost means to rapidly reduce exposure to arsenic when accompanied by effective education.
  
  
• Blend low-arsenic water with higher-arsenic water to achieve an acceptable arsenic concentration level.
  
  
• Install arsenic removal systems – either centralized or domestic – and ensure the appropriate disposal of the removed arsenic. Technologies for arsenic removal include oxidation, coagulation-precipitation, absorption, ion exchange, and membrane techniques. There is an increasing number of effective and low-cost options for removing arsenic from small or household supplies, though there is still limited evidence about the extent to which such systems are used effectively over sustained periods of time.
  

The most important action in affected communities is the prevention of further exposure to arsenic by the provision of a safe water supply for drinking, food preparation and irrigation of food crops. There are a number of options to reduce levels of arsenic in drinking-water.

Long-term actions are also required to reduce occupational exposure from industrial processes.
Education and community engagement are key factors for ensuring successful interventions. There is a need for community members to understand the risks of high arsenic exposure and the sources of arsenic exposure, including the intake of arsenic by crops (e.g. rice) from irrigation water and the intake of arsenic into food from cooking water.

High-risk populations should also be monitored for early signs of arsenic poisoning – usually skin problems.

In 2015, there were 1,135 health-based violations of the Arsenic Rule by 352 community water systems across the country. 

The systems in violation served 358,323 people. 

Nationally, these states and territories had the highest populations served by violating systems: 

Texas (124,535 people served)
California (104,659 people served)
New Mexico (34,732 people served)
Tribal Lands in EPA Region 9 (14,002 people served)
New Jersey (13,642 people served) 

When ranked by percentage of population served by community water systems with violations of the Arsenic Rule, New Mexico ranked the highest, with 1.7 percent of the population served by violating systems.b

WHO Response

Arsenic is one of WHO’s 10 chemicals of major public health concern. WHO’s work to reduce arsenic exposure includes setting guideline values, reviewing evidence, and providing risk management recommendations. WHO publishes a guideline value for arsenic in its Guidelines for drinking-water quality. The Guidelines are intended for use as the basis for regulation and standard setting worldwide.

The current recommended limit of arsenic in drinking-water is 10 μg/L, although this guideline value is designated as provisional because of practical difficulties in removing arsenic from drinking-water. Every effort should therefore be made to keep concentrations as low as reasonably possible and below the guideline value when resources are available.

However, millions of people around the world are exposed to arsenic at concentrations much higher than the guideline value (100 μg/L or greater), and therefore the public health priority should be to reduce exposure for these people. Where it is difficult to achieve the guideline value, Member States may set higher limits or interim values as part of an overall strategy to progressively reduce risks, while taking into account local circumstances, available resources, and risks from low arsenic sources that are contaminated microbiologically.

The WHO/UNICEF Joint Monitoring Programme for Water Supply, Sanitation and Hygiene monitors progress towards global targets on drinking water. Under the new 2030 Agenda for Sustainable Development, the indicator of "safely managed drinking water services" calls for tracking the population accessing drinking water which is free of faecal contamination and priority chemical contaminants, including arsenic.

Key Facts About Harmful Lead

• Lead is a cumulative toxicant that affects multiple body systems and is particularly harmful to young children.
  
• Lead in the body is distributed to the brain, liver, kidney and bones. It is stored in the teeth and bones, where it accumulates over time. Human exposure is usually assessed through the measurement of lead in blood.
  
• Lead in bone is released into blood during pregnancy and becomes a source of exposure to the developing fetus.
  
• There is no known level of lead exposure that is considered safe.
• Exposure to lead is particularly toxic to children and can cause serious, irreversible damage to their developing brains and nervous systems. Exposure can also cause miscarriages and stillbirths in pregnant women, as well as fertility issues, cardiovascular and kidney effects, cognitive dysfunction, and elevated blood pressure in healthy adults. 
• In 2015, there were 8,044 violations by systems serving 18,350,633 people (including 303 health-based violations by systems serving 582,302 people). 
• Formal enforcement action was taken in 12.0 percent of the cases (and in 14.2 percent of health-based cases). 
• Nearly 1 in 20 violations (and less than 1 in 10 health-based violations) returned to compliance within the calendar year.
  
• Lead exposure is preventable.
  

Lead is a naturally occurring toxic metal found in the Earth’s crust. Its widespread use has resulted in extensive environmental contamination, human exposure and significant public health problems in many parts of the world.

Important sources of environmental contamination include mining, smelting, manufacturing and recycling activities, and, in some countries, the continued use of leaded paint, leaded gasoline, and leaded aviation fuel. More than three quarters of global lead consumption is for the manufacture of lead-acid batteries for motor vehicles. Lead is, however, also used in many other products, for example pigments, paints, solder, stained glass, lead crystal glassware, ammunition, ceramic glazes, jewellery, toys and in some cosmetics and traditional medicines. Drinking water delivered through lead pipes or pipes joined with lead solder may contain lead. Much of the lead in global commerce is now obtained from recycling.

Young children are particularly vulnerable to the toxic effects of lead and can suffer profound and permanent adverse health effects, particularly affecting the development of the brain and nervous system. Lead also causes long-term harm in adults, including increased risk of high blood pressure and kidney damage. Exposure of pregnant women to high levels of lead can cause miscarriage, stillbirth, premature birth and low birth weight, as well as minor malformations.

Sources and Routes of Exposure of Lead & Copper

People can become exposed to lead through occupational and environmental sources. This mainly results from:

Inhalation of lead particles generated by burning materials containing lead, for example, during smelting, recycling, stripping leaded paint, and using leaded gasoline or leaded aviation fuel; and ingestion of lead-contaminated dust, water (from leaded pipes), and food (from lead-glazed or lead-soldered containers).

The use of some traditional cosmetics and medicines can also result in lead exposure.

Young children are particularly vulnerable because they absorb 4–5 times as much ingested lead as adults from a given source. Moreover, children’s innate curiosity and their age-appropriate hand-to-mouth behaviour result in their mouthing and swallowing lead-containing or lead-coated objects, such as contaminated soil or dust and flakes from decaying lead-containing paint. This route of exposure is magnified in children with pica (persistent and compulsive cravings to eat non-food items), who may, for example pick away at, and eat, leaded paint from walls, door frames and furniture. Exposure to lead-contaminated soil and dust resulting from battery recycling and mining has caused mass lead poisoning and multiple deaths in young children in Nigeria, Senegal and other countries.

Once lead enters the body, it is distributed to organs such as the brain, kidneys, liver and bones. The body stores lead in the teeth and bones where it accumulates over time. Lead stored in bone may be remobilized into the blood during pregnancy, thus exposing the fetus. Undernourished children are more susceptible to lead because their bodies absorb more lead if other nutrients, such as calcium, are lacking. Children at highest risk are the very young (including the developing fetus) and the impoverished.

Lead pipes have been used for centuries to deliver water. More recently, in the 1880s, cities around the United States began installing lead pipes on a large scale. Lead pipes were often used because they are more malleable and can last longer than iron pipes. Experts have estimated that 6 to 10 million lead service lines, which connect local water mains to individual residences, are being used in the United States, serving 15 to 22 million Americans. Most were installed at least 50 years ago, though some were added more recently. 

Because corrosive contaminants in water can cause lead to be released from pipes and fittings, national restrictions on lead pipes and lead containing plumbing fixtures were introduced in 1986. These restrictions were, however, fairly weak until a law allowing no more than 0.25 percent lead content went into effect in 2014. 

Copper can also enter drinking water through plumbing materials. It is used in the manufacture of wire, plumbing pipes, and sheet metal and is also combined with other metals to make brass and bronze pipes and faucets.

Health Effects of Lead Poisoning on Children

Lead can have serious consequences for the health of children. At high levels of exposure, lead attacks the brain and central nervous system to cause coma, convulsions and even death. Children who survive severe lead poisoning may be left with mental retardation and behavioural disorders. At lower levels of exposure that cause no obvious symptoms, and that previously were considered safe, lead is now known to produce a spectrum of injury across multiple body systems. In particular lead can affect children’s brain development resulting in reduced intelligence quotient (IQ), behavioural changes such as reduced attention span and increased antisocial behaviour, and reduced educational attainment. Lead exposure also causes anaemia, hypertension, renal impairment, immunotoxicity and toxicity to the reproductive organs. The neurological and behavioural effects of lead are believed to be irreversible.

There is no known safe blood lead concentration. But it is known that, as lead exposure increases, the range and severity of symptoms and effects also increases. Even blood lead concentrations as low as 5 µg/dL, once thought to be a “safe level”, may be associated with decreased intelligence in children, behavioural difficulties, and learning problems.

Encouragingly, the successful phasing out of leaded gasoline in most countries, together with other lead control measures, has resulted in a significant decline in population-level blood lead concentrations. There are now only 3 countries that continue to use leaded fuel(1).

Burden of Disease From Lead Exposure

The Institute for Health Metrics and Evaluation (IHME) has estimated that, based on 2015 data, lead exposure accounted for 494 550 deaths and loss of 9.3 million disability-adjusted life years (DALYs) due to long-term effects on health. The highest burden is in low- and middle-income countries. IHME also estimated that lead exposure accounted for 12.4% of the global burden of idiopathic developmental intellectual disability, 2.5% of the global burden of ischaemic heart disease and 2.4% of the global burden of stroke (2).

Exposure to copper can affect the digestive, hematological (blood forming), and liver systems.

In 2015, there were 8,044 violations of the Lead and Copper Rule by 5,367 community water systems across the country. 

The systems in violation served 18,350,633 people. 

Nationwide, the largest populations served by systems with violations to the Lead and Copper Rule were found in: 

Texas (6,910,988 people served)
Puerto Rico (3,379,808 people served)
Florida (1,753,865 people served)
Georgia (1,378,155 people served)
Massachusetts (1,117,415 people served) 

When ranked by percentage of population served by community water systems with violations of the Lead and Copper Rule, Puerto Rico ranked the highest, with 97.2 percent of its population served by violating systems.

In 2015, there were 303 health-based violations of the Lead and Copper Rule by 233 community water systems across the country. 

The systems in violation served 582,302 people. 

Nationally, the states or territories with the largest populations served by violating systems were: 

Wisconsin (154,720 people served)
Florida (117,139 people served)
Texas (71,849 people served)
North Carolina (65,928 people served)
Illinois (57,338 people served) 

Of the states/territories with violations to the Lead and Copper Rule, Wisconsin had the highest percentage of its population (2.7 percent) served by violating systems.

Of the 8,044 reported violations of the Lead and Copper Rule in 2015, formal enforcement action was taken by the EPA or the states in only 12.0 percent of cases.c Only about 1 in 20 violations (6.2 percent; 501 violations) returned to compliance within the calendar year. For health-based violations of the Lead and Copper Rule, formal enforcement action was taken by the EPA or the states for 14.2 percent of the 303 violations reported in 2015. A little less than 1 in 12 of all health-based violations (8.6 percent; 26 violations) returned to compliance within the calendar year.

WHO Response

WHO has identified lead as 1 of 10 chemicals of major public health concern, needing action by Member States to protect the health of workers, children and women of reproductive age.

WHO has made available through its website a range of information on lead, including information for policy makers, technical guidance and advocacy materials.

WHO is currently developing guidelines on the prevention and management of lead poisoning, which will provide policy-makers, public health authorities and health professionals with evidence-based guidance on the measures that they can take to protect the health of children and adults from lead exposure.

Since leaded paint is a continuing source of exposure in many countries, WHO has joined with United Nations Environment Programme to form the Global Alliance to Eliminate Lead Paint. This is a cooperative initiative to focus and catalyse efforts to achieve international goals to prevent children’s exposure to lead from leaded paints and to minimize occupational exposures to such paint. Its broad objective is to promote a phase-out of the manufacture and sale of paints containing lead and eventually eliminate the risks that such paints pose.

The Global Alliance to Eliminate Lead Paint is an important means of contributing to the implementation of paragraph 57 of the Plan of implementation of the World Summit on Sustainable Development and to resolution II/4B of the Strategic Approach to International Chemicals Management (SAICM), which both concern the phasing out of lead paint. The elimination of lead paint will contribute to the achievement of Sustainable Development Goal target 3.9: 

By 2030 substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water, and soil pollution and contamination; and target 12.4: By 2020, achieve the environmentally sound management of chemicals and all wastes throughout their life cycle, in accordance with agreed international frameworks, and significantly reduce their release to air, water and soil in order to minimize their adverse impacts on human health and the environment.

The U.S. Environmental Protection Agency (EPA) has regulated lead in drinking water since it first issued interim standards under the Safe Drinking Water Act for about two dozen contaminants including lead in 1975.

In 1991, the EPA rescinded the 1975 interim maximum contaminant level for lead and replaced it with the Lead and Copper Rule, a complex treatment technique to control lead levels in tap water. This rule is intended in part to address the release of lead from pipes and fittings from corrosive water, so it generally requires corrosion control. 

Thus, under the Lead and Copper Rule, every water system serving more than 50,000 people must either treat its water to “optimize corrosion control” or demonstrate that it doesn’t need to do so because its water isn’t corrosive and there are no lead problems. 

The Lead and Copper Rule generally requires water systems to add a corrosion inhibitor (such as orthophosphate), which coats the inside of the pipes with a thin film that can reduce the amount of lead that leaches into the water. The benefits of corrosion control to both private homeowners and public utilities exceed the treatment costs. Corrosion control reduces pipe breaks and leaks and makes pipes, water heaters, radiators, and plumbing components last longer. All water systems are also required to test a specified number of drinking water taps in high-risk areas (i.e., in homes served by lead service lines or homes likely to have lead in their household plumbing or fixtures). The bigger the system, the more taps that must be tested, with a maximum of 100 required in large cities. 

Under the Lead and Copper Rule, if more than 10 percent of the tested taps contain lead above the action level of 15 ppb, the water system must take measures to reduce lead levels. These measures include better corrosion control and removal of lead service lines over a specified time period. The water system must conduct source water monitoring within 6 months and install source water treatment, and it must deliver public education within 60 days of the exceedance. Under the rule, the system must replace lead service lines if the lead action level is exceeded even after installing treatment. 

For copper, if more than 10 percent of the tested taps contain copper above the action level of 1.3 ppm, the water system must begin corrosion control steps, conduct source water monitoring within 6 months, and install source water treatment.

• Exposure to nitrates and nitrites can lead to blue baby syndrome in infants, developmental effects, and cardiovascular disease. In extreme cases, blue baby syndrome can be severe and lead to death. 

• In 2015, there were 1,529 violations (459 of them health-based) at community water systems serving 3,867,431 people (1,364,494 health-based). 

• Formal enforcement action was taken in 11.3 percent of all cases (and 27.9 percent of health based cases). 

• Less than half of the violations (and about one-sixth of health-based violations) returned to compliance within the calendar year.

When the body reduces ingested nitrates to nitrites, the resulting condition can cause a temporary blood disorder in infants called methemoglobinemia, or blue baby syndrome. Nitrites absorbed through the stomach react with hemoglobin to form methemoglobin, which cannot carry oxygen with the same capacity as hemoglobin. This impairs the body’s ability to carry oxygen to body tissues, resulting in an oxygen deficiency in the infant’s blood.

This acute condition usually occurs in infants less than six months old, developing rapidly over a period of days. Symptoms include shortness of breath and blueness of skin, especially around the eyes and mouth. When the nitrate-contaminating source is removed from the body, the effects may be reversible. Blue baby syndrome may lead to coma and eventual death.

While methemoglobinemia is rare in adults, pregnant women are particularly susceptible to the condition, since it is common for methemoglobin levels to increase during pregnancy. It is therefore especially important that pregnant women be sure that the nitrate concentrations in their drinking water are at safe levels. People with medical conditions such as reduced stomach acidity may also be more vulnerable to the harmful effects of methemoglobinemia, such as abdominal cramps and vomiting. Long-term exposure to nitrates and nitrates at levels above the maximum contaminant level (MCL) may also have effects on thyroid function and development as well as on cardiovascular health.
The International Agency for Research on Cancer, a research arm of the World Health Organization, also has classified nitrates and nitrites as probable carcinogens in certain circumstances.

In 1992, the U.S. Environmental Protection Agency (EPA) set the maximum contaminant level goal (MCLG) and MCL for nitrates at 10 parts per million (ppm) and for nitrites at 1 ppm. The EPA reviewed nitrates and nitrites as part of a required Six Year Review and retained those standards as still protective of human health.

Nitrates and nitrites have different sampling requirements. All public water systems are required to monitor for the presence of nitrates. Both ground and surface water community water systems must conduct monitoring annually. Increased monitoring is required where results detect nitrate levels greater than the MCL for ground water systems, and greater than one half of the MCL for surface water systems, for at least four consecutive quarters until the state determines that that the system reliably and consistently meets the detection limit. Some states require surface water systems to monitor monthly because they are more vulnerable to contamination from agricultural runoff. 

Public water systems must also monitor for the presence of nitrites. Under EPA regulations, if any system meets or exceeds the trigger level (one-half the MCL) for nitrite at any time, the system must conduct quarterly sampling beginning in the next quarter. The state may allow a system to reduce the quarterly sampling to annual sampling provided four quarterly results are reliably and consistently below the MCL.

In 2015, there were 1,529 violations of nitrate and nitrite standards by 971 community water systems across the country. 

The systems in violation served 3,867,431 people. 

Nationwide, these states had the largest populations served by violating systems: 

• Ohio (1,159,887 people served) 
  
• Texas (908,380 people served) 
  
• Connecticut (459,690 people served) 
  
• Florida (238,182 people served) 
  
• New Jersey (188,529 people served) 
  

When ranked by percentage of population served by community water systems with violations of nitrate and nitrite standards, Connecticut ranked the highest, with 12.8 percent of its population served by violating systems.

In 2015, there were 459 health-based violations of nitrate and nitrite standards by 192 community water systems across the country. 

The systems in violation served 1,364,494 people. 

Nationally, these states had the largest populations served by violating systems: 

• Ohio (1,159,887 people served) 
  
• Iowa (72,734 people served) 
  
• Texas (28,644 people served) 
  
• Wisconsin (25,005 people served) 
  
• Nebraska (18,079 people served) 
  

Of the states/territories with health-based violations of nitrate and nitrite standards, Ohio had the highest percentage of its population (10.0 percent) served by violating systems.

Exposure to radionuclides can lead to cancers and changes in kidney function. 

In 2015, there were 2,297 violations (962 of them health-based) in community water systems serving 1,471,364 people (445,969 health-based). 

Formal enforcement was taken in 11.7 percent of all cases (and 16.1 percent of health-based cases). 

About one in five violations (and about one in twenty health-based violations) returned to compliance within the calendar year.

Radionuclide refers to radioactive forms of elements.

Most radionuclides found in drinking water sources are naturally occurring radioactive particles found in the earth’s crust and created in the upper atmosphere.

Many drinking water sources contain radionuclides at levels so low that they are not considered a big health concern. Of special concern, however, are naturally occurring uranium and the radioisotopes radium-226 and radium-228, which have been found at elevated levels in some drinking water sources.

Anthropogenic, or human-made, radionuclides are primarily beta and photon emitters, created through the production of electricity, nuclear weapons, nuclear medicines, and commercial products. These radionuclides may be released into drinking water sources through improper waste storage, leaks, or transportation accidents. Higher levels of radionuclides tend to be found in groundwater sources than in surface water sources.

Radionuclides are known to cause cancer, and exposure to radionuclides in drinking water is reasonably anticipated to increase the risk of cancer in humans.

Radioactive particles emitted by radionuclides cause cellular damage in chromosomes and other parts of the cell as they travel through the body. This can result in uncontrolled cellular production, leading to cancer. 

Radium, for example, accumulates in the bones, while iodine accumulates in the thyroid. In addition to its carcinogenic affects, ingestion of elevated levels of uranium in drinking water can cause changes in kidney function that are indicators of potential future kidney failure.1

The U.S. Environmental Protection Agency (EPA) regulates the following radionuclides: combined radium-226/228; (adjusted) gross alpha, beta particle, and photon radioactivity; and uranium. 

The maximum contaminant level (MCL) for radium (combined 226/228) is 5 picocuries (a measurement of radioactivity) per liter of water (abbreviated as pCi/L). The MCL for uranium is 30 parts per billion (ppb), which was expected to result in reduced uranium exposures for 620,000 people. 

The MCL for gross alpha particles is 15 pCi/L, not including radon and uranium.14 The beta/photon emitters have an MCL of 4 millirems (a measure of absorbed radiation dose) per year (abbreviated as mrem/yr), which can be calculated based on a total of 168 beta particle and photon emitters. 

When the EPA issued its drinking water standards for radionuclides, the rule was expected to require fewer than 800 systems to install treatment. The final rule was issued with three additional analytical methods for determining the concentration of radionuclides in drinking water.

The Standardized Monitoring Framework for radionuclides is complex. All entry points into the drinking water system (for example, each well that pumps water into the system) must be tested, and monitoring requirements are consistent with the monitoring requirements for other, comparable drinking water contaminants. 

States are not permitted to issue waivers for the radionuclide monitoring requirements.However, states may waive the final two calendar quarters of initial monitoring for gross alpha, uranium, radium-226, and radium-228, if the sampling results from the previous two quarters are below the detection limit. Only systems that are vulnerable to beta / photon emitters must sample for gross beta, tritium, and strontium-90.

In 2015, there were 2,297 violations of the Radionuclide Rule by 523 community water systems across the country. 

The systems in violation served 1,471,364 people. 

Nationwide, the following states had the largest populations served by violating systems: 

Utah (243,999 people served)
Wisconsin (197,230 people served)
New Jersey (170,786 people served)
Pennsylvania (169,648 people served)
Arizona (78,468 people served) 

When ranked by percentage of population served by community water systems with violations of the Radionuclide Rule, Utah ranked the highest, with 8.1 percent of its population served by systems with violations.

In 2015, there were 962 health-based violations of the Radionuclide Rule by 258 community water systems across the country. 

The systems in violation served 445,969 people. 

Nationally, these states had the highest populations served by violating systems:
Wisconsin (117,117 people served)
Texas (58,881 people served)
California (57,834 people served)
Iowa (50,230 people served)
Illinois (45,555 people served) 

When ranked by percentage of population served by community water systems with violations of the Radionuclide Rule, Wisconsin ranked the highest, with 2.0 percent of the population served by violating systems.

Of the 2,297 reported violations of the Radionuclide Rule in 2015, formal enforcement action was taken by the EPA or the states in 11.7 percent of cases. A little less than one-fifth of violations (434 violations) returned to compliance within the calendar year. For health-based violations of the Radionuclide Rule, formal enforcement action was taken by the EPA or the states in 16.1 percent of the 962 violations reported in 2015. Only about one in twenty health-based violations (5.82 percent; 56 violations) returned to compliance within the calendar year.

The purpose of a public or private water treatment facility is to make water potable (safe to drink) and palatable (pleasant to taste) while also ensuring that there is a sufficient supply of water to meet the community’s needs. 

Raw and untreated water is obtained from an underground aquifer (usually through wells) or from a surface water source, such as a lake or river. It is pumped, or flows, to a treatment facility. Once there, the water is pre-treated to remove debris such as leaves and silt. Then, a sequence of treatment processes — including filtration and disinfection with chemicals or physical processes — eliminates disease-causing microorganisms. When the treatment is complete, water flows out into the community through a network of pipes and pumps that are commonly referred to as the distribution system.

What’s the difference between public and private water treatment facilities?

Public, municipal systems are owned and operated by the cities or towns they serve, and they’re typically under the management of a mayor or other elected official. 

Private systems range from individual wells serving a single household, to small corporate associations that provide water to a small group of homes, or to large corporations that have their own water service divisions. 

Whether public or private, all U.S. water utilities that serve more than 25 people must adhere to water quality standards established by the U.S. Environmental Protection Agency (EPA) as well as state and local regulations.

Point-of-Use (POU) devices treat water at the point of consumption. The technology provides the final barrier to the contaminants of concern before the water is consumed or used. Some commonly used technologies include:

• Activated Carbon
• Reverse Osmosis
• Ultraviolet (UV) Technologies
• Distillation

Point-of-Entry (POE) devices are whole-house treatment systems mainly designed to reduce contaminants in water intended for showering, washing dishes and clothes, brushing teeth, and flushing toilets.

 

• Ion Exchange
• Activated Carbon
• Filtration

Your first diagnostic tools are your senses. You can, at times, see, taste, smell, and feel contaminated water. Water that is red, orange, yellow, brown, or cloudy can signal iron, rust, or other contaminants in the mains or your household plumbing. Tannins from decaying vegetation and leaves can also give water a yellow or brownish hue.

The main perceptible signs of water issues include:

• Scale Deposits
• Staining
• Bad Taste & Smell
• Cloudiness & Discoloration
• Corrosion

Foul-smelling or bad-tasting water are signs of impurities. Here are common water odor or taste problems you might encounter:

• A rotten-egg or sulfur smell or taste suggests the presence of hydrogen sulfide. That’s often caused by a certain type of bacteria in the water. Sulfates can also cause the water to taste salty. Investigate further to pinpoint the source, such as bacteria growing in drains, water heaters, wells, or on the inside of pipes. 

• Musty, earthy odors and tastes may signal dissolved solids. Such aromas and tastes may be caused by decaying organic matter in the plumbing or even in the source water itself. 

• Then there’s the smell and taste of chlorine. It’s there for disinfection to make water safer to drink and originates during the normal chlorination treatment process, but to enjoy the taste you may want to get rid of it. 

• If water smells or tastes like turpentine or other chemicals that might indicate the presence of methyl tertiary butyl ether (MTBE) or xylenes, byproducts of gasoline refining, paints, detergents, or inks.

• Metallic smells and tastes may be a sign of mercury, lead, copper, arsenic, or iron in the water. Manganese and zinc may also cause a metallic smell or taste. These chemicals may come from the pipes themselves.

Hard water is a common quality of water which contains dissolved compounds of calcium and magnesium and, sometimes, other divalent and trivalent metallic elements. 

 The term hardness was originally applied to waters that were hard to wash in, referring to the soap wasting properties of hard water. Hardness prevents soap from lathering by causing the development of an insoluble curdy precipitate in the water; hardness typically causes the buildup of hardness scale (such as seen in cooking pans). Dissolved calcium and magnesium salts are primarily responsible for most scaling in pipes and water heaters and cause numerous problems in laundry, kitchen, and bath. Hardness is usually expressed in grains per gallon (or ppm) as calcium carbonate equivalent.

The degree of hardness standard as established by the American Society of Agricultural Engineers (S-339) and the Water Quality Association (WQA) is:

Degree of Hardness	Grains per Gallon (gpg)	ppm (or mg/L)
Soft	<1.0	<17.0
Slightly Hard	1.0-3.5	17.1-60
Moderately Hard	3.5-7.0	60-120
Hard	7.0-10.5	120-180
Very Hard	>10.5	>180

Symptoms include:

• Stiff, dingy laundry
• Mineral deposits on dishes and glassware 
• High soap usage & need for fabric softeners 
• Dry, itchy skin and scalp 
• Unmanageable hair 
• Extra work to remove soap curd on bathtubs & shower stalls 
• High energy costs, possibly due to scale build-up in pipes and on appliances
• Scale build up in sinks, tubs, faucets & appliances

Patterns of hardness in the United States are shown on the map of accounting units below. Softest waters were in parts of New England, the South Atlantic-Gulf States, the Pacific Northwest, and Hawaii. Moderately hard waters were common in many rivers of Alaska and Tennessee, in the Great Lakes region, and the Pacific Northwest. Moderately hard waters were common in many rivers of Alaska and Tennessee, the Great Lakes region, and the Pacific Northwest. Hard and very hard waters were found in some streams in most of the regions throughout the country. Hardest waters (greater than 1,000 mg/L) were measured in streams in Texas, New Mexico, Kansas, Arizona, and southern California.

Water treatment can improve hardness issues.

Scale deposits from hardness buildup affects fixtures and appliances found throughout the entire home or business. For this reason, hardness is typically addressed with treatment of water for the whole house or building rather than just at a specific faucet. Hardness minerals can be reduced in water for the whole house to make it “softer” by using one of the following means:

• Chemical softening—lime softening, hot and cold; lime-soda softening

• Membrane separation softening—Nano filtration

• Cation exchange softening—inorganic, carbonaceous, or organic base exchangers
  

If hard water is your problem there are 2 solutions to fix it: POE and POU

Reverse Osmosis is a technology that is used to remove a large majority of harmful contaminants from drinking water by moving the water under pressure through a semipermeable membrane. In most households in US that use municipal water source, the pressure present is sufficient without needing to install a RO pump. 

Water Tastes Refreshing And Delicious
Reverse Osmosis filtration improves taste, odor and appearance of water by removing contaminants that cause taste and odor problems.

RO Is The Most Cost Effective Water Filtration Solution

Are you buying water at water dispensaries, bottled water or get it delivered? You can cancel your water delivery service and stop purchasing cases of bottled water. Reverse Osmosis filtration provides “better-than-bottled water” quality water for just pennies per gallon.

Easy Maintenance DIY Systems

The RO systems are built for DIY installation. With that in mind we build them with the least amount of necessary components and filters to solve your particular water problem and not add to your maintenance costs. They are easy to self service and clean. 

Reverse Osmosis Is The Best Solution To Remove The Most Harmful Contaminants

RO system removes most if not all contaminants from tap water including lead, iron, aluminium, chlorine, chloramines, nitrates, pesticides, sulfates, fluoride, bacteria, viruses, pharmaceuticals, arsenic, asbestos and much more. Each Reverse Osmosis system comes with additional filters such as sediment filter and activated carbon to remove sand, chlorine, chloramine before water gets processed through a reverse osmosis membrane.

Reverse Osmosis removes dissolved inorganic solids (such as salts) from water by the help of water pressure pushing the tap water through a semipermeable membrane. This reverse osmosis membrane removes particles that are 0.0001 micron in size - 500,000 smaller than a diameter of a single strand of a human hair. Tiny. Other types of filtrations such as UltraFiltration (UF) remove particles that are 0.01 in size.

There are several types of impurities in water that RO removes such as: Fluoride, Chlorine, Chloramine, Lead, Copper, Iron, Pesticides, Detergents, Nitrates, Sulfates, Asbestos, Arsenic, Excess of Minerals, Salts and more.

After water passes through sediment, carbon filters and the RO membrane, all of the impurities are separated and removed through the drain. When RO is installed, you or the handyman will drill a small hole in the drain pipe and attach a water line to push toxins out so they don't re-contaminate the water. 

After this water is filtered, you are left with a safe, clean-tasting and delicious drinking water that doesn't have a bad taste or smell.  RO has been used for home water filtration since 1977 with an increased popularity because this is the safest, most cost effective and easy to maintain way to purify your drinking water at home, office or small business. There are also commercial RO units and the size of RO systems depends on the amount of water the filters and membranes must process daily.

What is TDS and why you should care.
Total "Dissolved solids" refer to any minerals, salts, metals, cations or anions dissolved in water. Because all contaminants have conductivity levels that may be detected by TDS meter this includes anything present in water other than the pure water molecules and suspended solids. 

Suspended solids - any particles and substances that do not dissolve nor settle in the water, such as calcium particles.
 
 The total dissolved solids (TDS) concentration = sum of the cations (positively charged) and anions (negatively charged) ions in the water.

PPM - Parts per Million (ppm) is the weight-to-weight ratio of any ion to water. 

Conductivity is usually about 100 times the total cations or anions expressed as equivalents. Total dissolved solids (TDS) in ppm usually ranges from 0.5 to 1.0 times the electrical conductivity. 

Dissolved solids come from organic sources such as leaves, silt, plankton, and industrial waste and sewage. Other sources come from runoff from urban areas, road salts used on street during the winter, and fertilizers and pesticides used on lawns and farms. 

Dissolved solids also come from inorganic materials such as rocks and air that may contain calcium bicarbonate, nitrogen, iron phosphorus, sulfur, and other minerals. Many of these materials form salts, which are compounds that contain both a metal and a nonmetal. Salts usually dissolve in water forming ions. Ions are particles that have a positive or negative charge. 

 Water may also pick up metals such as lead or copper as they travel through pipes used to distribute water to consumers.

The EPA advises a maximum contamination level (MCL) of 500mg/liter (500 parts per million (ppm)) for TDS. 

Numerous water supplies exceed this level. When TDS levels exceed 1000mg/L it is generally considered unfit for human consumption. 

A high level of TDS is an indicator of potential concerns, and warrants further investigation. Most often, high levels of TDS are caused by the presence of potassium, chlorides and sodium. These ions have little or no short-term effects, but toxic ions (lead arsenic, cadmium, nitrate and others) may also be dissolved in the water. 
 

Below are some of the reasons why it is helpful to constantly test for TDS:
 

Taste/Health	High TDS results in undesirable taste which could be salty, bitter, or metallic. It could also indicate the presence of toxic minerals. The EPA's recommended maximum of TDS in water is 500mg/L (500ppm).
Filter performance	Test your water to make sure the filter system has a high rejection rate and know when to change your filter (or membrane) cartridges.
Hardness	High TDS indicates Hard water, which causes scale buildup in pipes and valves, inhibiting performance.
Aquaculture	A constant level of minerals is necessary for aquatic life. The water in an aquarium should have the same levels of TDS and pH as the fish and reef's original habitat.
Hydroponics	TDS is the best measurement of the nutrient concentration in a hydroponics' solution.
Pools and Spas	TDS levels must be monitored to prevent maintenance problems.
Commercial/Industrial	High TDS levels could impede the functions of certain applications.

Ideal drinking water from reverse osmosis, deionization, microfiltration, distillation:  0-55 PPM

Often considered acceptable range for carbon filtration, mountain springs or aquifers: 50-140 PPM

Average tap water: 140-500 PPM

Hard water: 170 PPM +

Less desirable: 200-300 PPM

Unpleasant levels from tap water, aquifers, or mountain springs: 300-500PPM

EPA maximum contamination levels: 500 PPM