Drinking water quality in the United States
Encyclopedia
Drinking water quality in the United States is a source of concern about pollutants in certain localities. In 2006, 89.3 percent of the nation's community water systems were in compliance with all of more than 90 U.S. Environmental Protection Agency
(EPA) standards. Most of the systems out of compliance are small systems in rural areas and small towns. Drinking water quality in the U.S. is regulated by state and federal laws and codes
, which set Maximum Contaminant Level
s for some pollutants, determine various operational requirements and require utilities to publish consumer confidence reports.
these consumer confidence reports, written by utilities, "can be flawed, and some are essentially propaganda. They report yearly averages over time and, with some contaminants, over multiple locations within a system, which can obscure spikes." In addition, they don't necessarily list contaminants that aren't regulated and say nothing about contamination that may occur within the plumbing system of a building. A study of the 2001 water quality reports of 19 cities published by the Natural Resources Defense Council
gave two of them--Newark
and Phoenix
--a failing grade for "burying, obscuring and omitting findings about health effects of contaminants in city water supplies and printing misleading statements." Even the cities to which the study assigned grades of "Good" and "Fair" included some false claims, errors and misleading data.
over the previous five years. Violations involved arsenic, radioactive substances like uranium, tetrachloroethylene
, and coliform bacteria
. Fewer than 6 percent of the water systems that broke the law were ever fined or punished by state or federal officials. According to David Uhlmann, a former Justice Department
official, "there is significant reluctance within the EPA and Justice Department to bring actions against municipalities, because there’s a view that they are often cash-strapped, and fines would ultimately be paid by local taxpayers". A longtime EPA enforcement official who was quoted in the report said "The top people want big headlines and million-dollar settlements. That’s not drinking-water cases." State regulators rather provide technical assistance to help systems that violate the rules. But many systems remained out of compliance, even after aid was offered. For over a quarter of systems that violated the arsenic or radioactivity standards, there is even no record that they were ever contacted by a regulator.
occurs naturally in water or enters it through pollution. If a person drinks two liters (more than half a gallon) of tap water that exceeds the former Maximum Contaminant Level of 50 parts per billion (ppb) every day over a lifetime, there is a risk of cancer. EPA reduced this level to 10 parts per billion (ppb) in 2002 and drinking water systems had to comply with the new regulation until 2006. The National Research Council
estimates that men and women who daily consume water containing 20 ppb of arsenic have about a 0.7% increased risk of developing bladder or lung cancer during their lifetime. According to a recent film funded by the US Superfund
, , millions of private wells have unknown arsenic levels, and in some areas of the US, over 20 percent of wells may contain levels that are not safe.
is a parasite that has a thick outer shell and thus is highly resistant to disinfection with chlorine. It gets into rivers and lakes from the stools of infected animals. Municipal water treatment plants usually remove cryptosporidium oocysts through filtration. Nevertheless, at least five outbreaks of cryptosporidiosis
in the U.S. have been associated with contaminated drinking water, including a well-publicized one in Milwaukee, Wisconsin in 1993.
The Long Term 2 Enhanced Surface Water Treatment Rule ("LT2 rule") of 2006 requires evaluation of treatment plants and specific treatments be provided in order to minimize the potential for cryptosporidium infections from public water at supplies using surface water.
can react with natural material in the water to form disinfection by-products such as trihalomethanes. Animal studies indicate that none of the chlorination by-products studied to date is a potent carcinogen at concentrations normally found in drinking water. According to GreenFacts
, there is insufficient epidemiological
evidence to conclude that drinking chlorinated water causes cancers. The results of currently published studies do not provide convincing evidence that chlorinated water causes adverse pregnancy outcomes.
with the practice of intentionally adding fluoride to public drinking-water supplies for the prevention of tooth decay. However, fluoride can also enter public water systems from natural sources, including runoff from weathering of fluoride-containing rocks and soils and leaching from soil into groundwater. Fluoride pollution from various industrial emissions can also contaminate water supplies. In a few areas of the United States, fluoride concentrations in water are much higher than normal, mostly from natural sources. In 1986, EPA established a maximum allowable concentration for fluoride in drinking water of 4 milligrams per liter (mg/L). After reviewing research on various health effects from exposure to fluoride, the Committee on Fluoride in Drinking Water of the National Research Council concluded in 2006 that EPA's drinking water standard for fluoride does not protect against adverse health effects. Just over 200,000 Americans live in communities where fluoride levels in drinking water are 4 mg/L or higher. Children in those communities are at risk of developing severe tooth enamel
fluorosis
, a condition that can cause tooth enamel loss and pitting. It can also increase the risk of bone fractures. The report concluded unanimously that the present maximum contaminant level goal of 4 mg/L for fluoride should be lowered.
Several states have more stringent regulations.
in drinking water. Typically, lead gets into drinking water after the water leaves the treatment plant. The source of lead is most likely pipe or solder
in older service connections or older plumbing inside homes, from which lead "leaks" into the water through corrosion. EPA's lead and copper rule
set an "action level" of 15 parts per billion (ppb), which is different from a maximum contaminant level.
If tests show that the level of lead drinking water is in the area of 15 ppb or higher, it is advisable - especially if there are young children in the home - to replace old pipes, to filter water or to use bottled water. EPA estimates that more than 40 million U.S. residents use water "that can contain lead in excess of 15 ppb". In Washington, DC these concerns have led to a $408 million program carried out since 2004 to replace lead service connections to about 35,000 homes. The effectiveness of the program has, however, been put in question in 2008 by WASA
, the city's utility.
s to monitor for some of those substances.
is regulated by some states, including California and New York.
hormones by the body, chemicals that are essential for proper development of the fetus and for normal metabolic functioning of the body. According to patient advocate and writer Mary Shomon
, people with thyroid conditions, as well as pregnant women and their fetuses are particularly at risk. However, according to the Perchlorate Information Bureau, an industry-supported group, sound scientific and medical research shows that the low levels of perchlorate being detected in drinking water are not dangerous to human health. Still according to the same source, these studies on adults, newborns and children provide reason to believe that low levels of perchlorate (even at levels many times higher than the minute amounts being found in some drinking water supplies) also have no measurable effect on pregnant women or fetuses.
One source of perchlorate in drinking water is the past production of solid rocket propellants using perchlorate, combined with poor disposal practices. Industrial accidents and agricultural fertilizers are also suspected as sources of contamination of drinking water by perchlorate. Perchlorate is also found in breast milk at significant levels, possibly attributable to perchlorate in drinking water and foods.
The challenge of defining an acceptable level of perchlorates in drinking water sets two opposing groups with significantly different views against each other. In a draft risk assessment made in 2002 EPA suggested that levels higher than 1 part per billion (ppb) pose a health risk. In contrast, the Defense Department
contended that perchlorate at 200 ppb has no lasting effect on humans. Perchlorate is one of only four of the 70 chemicals for which EPA has set public health goals that have a safety factor of 10, rather than the usual safety factors of 100 or 1000. In October 2008 EPA refused to set a drinking water safety standard for perchlorate, saying that "in more than 99 percent of public drinking water systems, perchlorate was not at levels of public health concern" using a benchmark of 15 ppb. EPA encouraged states to set their own standards in accordance to local conditions. In 2004 eight states had non-binding advisories for perchlorate in drinking water, ranging from 1 to 18 ppb. Only two states--Massachusetts and California--set legally binding maximum contaminant levels on the allowable amount of perchlorate in drinking water, at 2 ppb and 6 ppb respectively. Environmental organizations have criticized EPA's decision not to set a federal drinking water safety standard for perchlorates. The environmental law firm Earthjustice
announced that it would file suit against the Agency.
published in March 2008. According to the AP report, researchers do not yet understand the exact risks from decades of persistent exposure to random combinations of low levels of pharmaceuticals.
Pharmaceuticals are included in a broader group of substances currently being studied by EPA, "Pharmaceuticals and Personal Care Products (PPCPs)." This group includes classes of common consumer products such as cosmetics, fragrances, vitamins and sunscreen products.
United States Environmental Protection Agency
The U.S. Environmental Protection Agency is an agency of the federal government of the United States charged with protecting human health and the environment, by writing and enforcing regulations based on laws passed by Congress...
(EPA) standards. Most of the systems out of compliance are small systems in rural areas and small towns. Drinking water quality in the U.S. is regulated by state and federal laws and codes
Drinking water quality legislation of the United States
In the United States, public drinking water is governed by the laws and regulations enacted by the federal and state governments. Certain ordinances may also be created at a more local level. The Safe Drinking Water Act is the principal federal law...
, which set Maximum Contaminant Level
Maximum Contaminant Level
Maximum Contaminant Levels are standards that are set by the United States Environmental Protection Agency for drinking water quality. An MCL is the legal threshold limit on the amount of a substance that is allowed in public water systems under the Safe Drinking Water Act...
s for some pollutants, determine various operational requirements and require utilities to publish consumer confidence reports.
Consumer Confidence Reports
EPA's Consumer Confidence Rule of 1998 requires most public water suppliers to provide consumer confidence reports (CCR), also known as annual water quality reports, to their customers. Each year by July 1 anyone connected to a public water system should receive in the mail an annual water quality report that tells where your water comes from and what's in it. Consumers can find out about these local reports on a map provided by EPA. According to the science writer Elizabeth RoyteElizabeth Royte
Elizabeth Royte is an American science/nature writer. She is best known for her books Garbage Land , The Tapir's Morning Bath: Solving the Mysteries of the Tropical Rain Forest , and Bottlemania: How Water Went on Sale and Why We Bought It Elizabeth Royte is an American science/nature writer. She...
these consumer confidence reports, written by utilities, "can be flawed, and some are essentially propaganda. They report yearly averages over time and, with some contaminants, over multiple locations within a system, which can obscure spikes." In addition, they don't necessarily list contaminants that aren't regulated and say nothing about contamination that may occur within the plumbing system of a building. A study of the 2001 water quality reports of 19 cities published by the Natural Resources Defense Council
Natural Resources Defense Council
The Natural Resources Defense Council is a New York City-based, non-profit, non-partisan international environmental advocacy group, with offices in Washington DC, San Francisco, Los Angeles, Chicago, and Beijing...
gave two of them--Newark
Newark, New Jersey
Newark is the largest city in the American state of New Jersey, and the seat of Essex County. As of the 2010 United States Census, Newark had a population of 277,140, maintaining its status as the largest municipality in New Jersey. It is the 68th largest city in the U.S...
and Phoenix
Phoenix, Arizona
Phoenix is the capital, and largest city, of the U.S. state of Arizona, as well as the sixth most populated city in the United States. Phoenix is home to 1,445,632 people according to the official 2010 U.S. Census Bureau data...
--a failing grade for "burying, obscuring and omitting findings about health effects of contaminants in city water supplies and printing misleading statements." Even the cities to which the study assigned grades of "Good" and "Fair" included some false claims, errors and misleading data.
Weak enforcement of standards
Enforcement of drinking water standards in small water systems is weak. According to a New York Times analysis published in December 2009, more than 20 percent of water treatment systems in the U.S. providing water to 49 million people have violated key provisions of the Safe Drinking Water ActSafe Drinking Water Act
The Safe Drinking Water Act is the principle federal law in the United States intended to ensure safe drinking water for the public. Pursuant to the act, the Environmental Protection Agency is required to set standards for drinking water quality and oversee all states, localities, and water...
over the previous five years. Violations involved arsenic, radioactive substances like uranium, tetrachloroethylene
Tetrachloroethylene
Tetrachloroethylene, also known under its systematic name tetrachloroethene and many other names, is a chlorocarbon with the formula Cl2C=CCl2. It is a colourless liquid widely used for dry cleaning of fabrics, hence it is sometimes called "dry-cleaning fluid." It has a sweet odor detectable by...
, and coliform bacteria
Coliform bacteria
Coliform bacteria are a commonly used bacterial indicator of sanitary quality of foods and water. They are defined as rod-shaped Gram-negative non-spore forming bacteria which can ferment lactose with the production of acid and gas when incubated at 35-37°C...
. Fewer than 6 percent of the water systems that broke the law were ever fined or punished by state or federal officials. According to David Uhlmann, a former Justice Department
United States Department of Justice
The United States Department of Justice , is the United States federal executive department responsible for the enforcement of the law and administration of justice, equivalent to the justice or interior ministries of other countries.The Department is led by the Attorney General, who is nominated...
official, "there is significant reluctance within the EPA and Justice Department to bring actions against municipalities, because there’s a view that they are often cash-strapped, and fines would ultimately be paid by local taxpayers". A longtime EPA enforcement official who was quoted in the report said "The top people want big headlines and million-dollar settlements. That’s not drinking-water cases." State regulators rather provide technical assistance to help systems that violate the rules. But many systems remained out of compliance, even after aid was offered. For over a quarter of systems that violated the arsenic or radioactivity standards, there is even no record that they were ever contacted by a regulator.
Arsenic
ArsenicArsenic
Arsenic is a chemical element with the symbol As, atomic number 33 and relative atomic mass 74.92. Arsenic occurs in many minerals, usually in conjunction with sulfur and metals, and also as a pure elemental crystal. It was first documented by Albertus Magnus in 1250.Arsenic is a metalloid...
occurs naturally in water or enters it through pollution. If a person drinks two liters (more than half a gallon) of tap water that exceeds the former Maximum Contaminant Level of 50 parts per billion (ppb) every day over a lifetime, there is a risk of cancer. EPA reduced this level to 10 parts per billion (ppb) in 2002 and drinking water systems had to comply with the new regulation until 2006. The National Research Council
United States National Research Council
The National Research Council of the USA is the working arm of the United States National Academies, carrying out most of the studies done in their names.The National Academies include:* National Academy of Sciences...
estimates that men and women who daily consume water containing 20 ppb of arsenic have about a 0.7% increased risk of developing bladder or lung cancer during their lifetime. According to a recent film funded by the US Superfund
Superfund
Superfund is the common name for the Comprehensive Environmental Response, Compensation, and Liability Act of 1980 , a United States federal law designed to clean up sites contaminated with hazardous substances...
, , millions of private wells have unknown arsenic levels, and in some areas of the US, over 20 percent of wells may contain levels that are not safe.
Cryptosporidium
CryptosporidiumCryptosporidium
Cryptosporidium is a protozoan that can cause gastro-intestinal illness with diarrhea in humans.Cryptosporidium is the organism most commonly isolated in HIV positive patients presenting with diarrhea...
is a parasite that has a thick outer shell and thus is highly resistant to disinfection with chlorine. It gets into rivers and lakes from the stools of infected animals. Municipal water treatment plants usually remove cryptosporidium oocysts through filtration. Nevertheless, at least five outbreaks of cryptosporidiosis
Cryptosporidiosis
Cryptosporidiosis, also known as crypto, is a parasitic disease caused by Cryptosporidium, a protozoan parasite in the phylum Apicomplexa. It affects the intestines of mammals and is typically an acute short-term infection...
in the U.S. have been associated with contaminated drinking water, including a well-publicized one in Milwaukee, Wisconsin in 1993.
The Long Term 2 Enhanced Surface Water Treatment Rule ("LT2 rule") of 2006 requires evaluation of treatment plants and specific treatments be provided in order to minimize the potential for cryptosporidium infections from public water at supplies using surface water.
Disinfection by-products
Disinfectants such as chlorineChlorine
Chlorine is the chemical element with atomic number 17 and symbol Cl. It is the second lightest halogen, found in the periodic table in group 17. The element forms diatomic molecules under standard conditions, called dichlorine...
can react with natural material in the water to form disinfection by-products such as trihalomethanes. Animal studies indicate that none of the chlorination by-products studied to date is a potent carcinogen at concentrations normally found in drinking water. According to GreenFacts
GreenFacts
GreenFacts, formerly the GreenFacts Foundation, is an international non-profit organization founded in 2001 in Brussels, Belgium. It produces short summaries of technical scientific reports for the public...
, there is insufficient epidemiological
Epidemiology
Epidemiology is the study of health-event, health-characteristic, or health-determinant patterns in a population. It is the cornerstone method of public health research, and helps inform policy decisions and evidence-based medicine by identifying risk factors for disease and targets for preventive...
evidence to conclude that drinking chlorinated water causes cancers. The results of currently published studies do not provide convincing evidence that chlorinated water causes adverse pregnancy outcomes.
Fluoride
Most people associate fluorideFluoride
Fluoride is the anion F−, the reduced form of fluorine when as an ion and when bonded to another element. Both organofluorine compounds and inorganic fluorine containing compounds are called fluorides. Fluoride, like other halides, is a monovalent ion . Its compounds often have properties that are...
with the practice of intentionally adding fluoride to public drinking-water supplies for the prevention of tooth decay. However, fluoride can also enter public water systems from natural sources, including runoff from weathering of fluoride-containing rocks and soils and leaching from soil into groundwater. Fluoride pollution from various industrial emissions can also contaminate water supplies. In a few areas of the United States, fluoride concentrations in water are much higher than normal, mostly from natural sources. In 1986, EPA established a maximum allowable concentration for fluoride in drinking water of 4 milligrams per liter (mg/L). After reviewing research on various health effects from exposure to fluoride, the Committee on Fluoride in Drinking Water of the National Research Council concluded in 2006 that EPA's drinking water standard for fluoride does not protect against adverse health effects. Just over 200,000 Americans live in communities where fluoride levels in drinking water are 4 mg/L or higher. Children in those communities are at risk of developing severe tooth enamel
Tooth enamel
Tooth enamel, along with dentin, cementum, and dental pulp is one of the four major tissues that make up the tooth in vertebrates. It is the hardest and most highly mineralized substance in the human body. Tooth enamel is also found in the dermal denticles of sharks...
fluorosis
Fluorosis
Fluorosis can refer to:* Dental fluorosis* Skeletal fluorosisSkeletal fluorosis can be caused by: Cryolite ....
, a condition that can cause tooth enamel loss and pitting. It can also increase the risk of bone fractures. The report concluded unanimously that the present maximum contaminant level goal of 4 mg/L for fluoride should be lowered.
Several states have more stringent regulations.
Lead
Another issue of concern is leadLead
Lead is a main-group element in the carbon group with the symbol Pb and atomic number 82. Lead is a soft, malleable poor metal. It is also counted as one of the heavy metals. Metallic lead has a bluish-white color after being freshly cut, but it soon tarnishes to a dull grayish color when exposed...
in drinking water. Typically, lead gets into drinking water after the water leaves the treatment plant. The source of lead is most likely pipe or solder
Solder
Solder is a fusible metal alloy used to join together metal workpieces and having a melting point below that of the workpiece.Soft solder is what is most often thought of when solder or soldering are mentioned and it typically has a melting range of . It is commonly used in electronics and...
in older service connections or older plumbing inside homes, from which lead "leaks" into the water through corrosion. EPA's lead and copper rule
Lead and copper rule
The "Lead and Copper Rule", or LCR, is a United States federal regulation which limits the concentration of lead and copper allowed in public drinking water at the consumer's tap, as well limiting the permissible amount of pipe corrosion occurring due to the water itself. The U.S...
set an "action level" of 15 parts per billion (ppb), which is different from a maximum contaminant level.
If tests show that the level of lead drinking water is in the area of 15 ppb or higher, it is advisable - especially if there are young children in the home - to replace old pipes, to filter water or to use bottled water. EPA estimates that more than 40 million U.S. residents use water "that can contain lead in excess of 15 ppb". In Washington, DC these concerns have led to a $408 million program carried out since 2004 to replace lead service connections to about 35,000 homes. The effectiveness of the program has, however, been put in question in 2008 by WASA
Wasa
Wasa may refer to any of the following:*Wasa Lake, a place in British Columbia, Canada*Wasabröd, a brandname used by the Swedish company AB Wasabröd*IK Wasa, a big Swedish club*Vasa , 17th century Swedish warship, formerly spelled Wasa...
, the city's utility.
Substances for which there are no federal standards
EPA maintains a list of substances which are proposed for regulation in drinking water. In an effort to assess the importance of certain substances as contaminants, the National Primary Drinking Water Regulations have required some public water systemPublic water system
The US Safe Drinking Water Act and derivative legislation define public water system as an entity that provides "water for human consumption through pipes or other constructed conveyances to at least 15 service connections or serves an average of at least 25 people for at least 60 days a year."The...
s to monitor for some of those substances.
MTBE
Methyl tert-butyl etherMethyl tert-butyl ether
Methyl tert-butyl ether, also known as methyl tertiary butyl ether and MTBE, is an organic compound with molecular formula 3COCH3. MTBE is a volatile, flammable, and colorless liquid that is immiscible with water. It has a minty odor vaguely reminiscent of diethyl ether, leading to unpleasant taste...
is regulated by some states, including California and New York.
Perchlorates
Perchlorates have been detected in public drinking water supplies of over 11 million people in 22 states at concentrations of at least 4 parts per billion (ppb). Above a certain concentration perchlorates alter the production of thyroidThyroid
The thyroid gland or simply, the thyroid , in vertebrate anatomy, is one of the largest endocrine glands. The thyroid gland is found in the neck, below the thyroid cartilage...
hormones by the body, chemicals that are essential for proper development of the fetus and for normal metabolic functioning of the body. According to patient advocate and writer Mary Shomon
Mary Shomon
Mary Shomon, born 1961, is an American health activist and author whose primary focus is thyroid disease.-Published work:She is the author of one New York Times best-selling book, The Thyroid Diet: Manage Your Metabolism for Lasting Weight Loss, published by Harper Collins in 2004, along with a...
, people with thyroid conditions, as well as pregnant women and their fetuses are particularly at risk. However, according to the Perchlorate Information Bureau, an industry-supported group, sound scientific and medical research shows that the low levels of perchlorate being detected in drinking water are not dangerous to human health. Still according to the same source, these studies on adults, newborns and children provide reason to believe that low levels of perchlorate (even at levels many times higher than the minute amounts being found in some drinking water supplies) also have no measurable effect on pregnant women or fetuses.
One source of perchlorate in drinking water is the past production of solid rocket propellants using perchlorate, combined with poor disposal practices. Industrial accidents and agricultural fertilizers are also suspected as sources of contamination of drinking water by perchlorate. Perchlorate is also found in breast milk at significant levels, possibly attributable to perchlorate in drinking water and foods.
The challenge of defining an acceptable level of perchlorates in drinking water sets two opposing groups with significantly different views against each other. In a draft risk assessment made in 2002 EPA suggested that levels higher than 1 part per billion (ppb) pose a health risk. In contrast, the Defense Department
United States Department of Defense
The United States Department of Defense is the U.S...
contended that perchlorate at 200 ppb has no lasting effect on humans. Perchlorate is one of only four of the 70 chemicals for which EPA has set public health goals that have a safety factor of 10, rather than the usual safety factors of 100 or 1000. In October 2008 EPA refused to set a drinking water safety standard for perchlorate, saying that "in more than 99 percent of public drinking water systems, perchlorate was not at levels of public health concern" using a benchmark of 15 ppb. EPA encouraged states to set their own standards in accordance to local conditions. In 2004 eight states had non-binding advisories for perchlorate in drinking water, ranging from 1 to 18 ppb. Only two states--Massachusetts and California--set legally binding maximum contaminant levels on the allowable amount of perchlorate in drinking water, at 2 ppb and 6 ppb respectively. Environmental organizations have criticized EPA's decision not to set a federal drinking water safety standard for perchlorates. The environmental law firm Earthjustice
Earthjustice
Earthjustice is a non-profit public interest law firm based in the United States that specializes in cases protecting natural resources, safeguarding public health, and promoting clean energy...
announced that it would file suit against the Agency.
Pharmaceutical substances
Many pharmaceutical substances are not regulated under the Safe Drinking Water Act. They have been found in tiny concentrations in the drinking water of several US cities affecting at least 41 million Americans, according to a five-month inquiry by the Associated PressAssociated Press
The Associated Press is an American news agency. The AP is a cooperative owned by its contributing newspapers, radio and television stations in the United States, which both contribute stories to the AP and use material written by its staff journalists...
published in March 2008. According to the AP report, researchers do not yet understand the exact risks from decades of persistent exposure to random combinations of low levels of pharmaceuticals.
Pharmaceuticals are included in a broader group of substances currently being studied by EPA, "Pharmaceuticals and Personal Care Products (PPCPs)." This group includes classes of common consumer products such as cosmetics, fragrances, vitamins and sunscreen products.
See also
- Drinking waterDrinking waterDrinking water or potable water is water pure enough to be consumed or used with low risk of immediate or long term harm. In most developed countries, the water supplied to households, commerce and industry is all of drinking water standard, even though only a very small proportion is actually...
- Drinking water quality legislation of the United StatesDrinking water quality legislation of the United StatesIn the United States, public drinking water is governed by the laws and regulations enacted by the federal and state governments. Certain ordinances may also be created at a more local level. The Safe Drinking Water Act is the principal federal law...
- Water pollutionWater pollutionWater pollution is the contamination of water bodies . Water pollution occurs when pollutants are discharged directly or indirectly into water bodies without adequate treatment to remove harmful compounds....
- Water qualityWater qualityWater quality is the physical, chemical and biological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set of standards against which...
- Water supply and sanitation in the United StatesWater supply and sanitation in the United StatesIssues that affect water supply and sanitation in the United States include water scarcity, pollution, a backlog of investment, concerns about the affordability of water for the poorest, and a rapidly retiring workforce...
- National Rural Water AssociationNational Rural Water AssociationThe National Rural Water Association, with its affiliated state rural water associations, is the largest water and wastewater utility membership organization in the United States of America. The NRWA is a professional organization that supports rural and small water utilities throughout the nation...
- Watershed centralWatershed CentralWatershed Central is an Environmental Protection Agency website developed to organize information and tools relevant to watershed management from across the country....
External links
- Drinking Water from Forests and Grasslands: A Synthesis of the Scientific Literature edited by George E. Dissmeyer, U.S. Forest Service.