Drinking water quality in the United States is generally safe. In 2016, over 90 percent of the nation's community water systems were in compliance with all published
U.S. Environmental Protection Agency
The Environmental Protection Agency (EPA) is an Independent agencies of the United States government, independent executive agency of the United States federal government tasked with environmental protection matters. President Richard Nixon pro ...
(EPA) standards.
Over 286 million Americans get their tap water from a community water system. Eight percent of the community water systems—large municipal water systems—provide water to 82 percent of the US population.
Most of the
public water systems (PWS) that are out of compliance are small systems in rural areas and small towns. For example, in 2015, 9% of water systems (21 million people) were reported as having water quality violations and therefore were at risk of drinking contaminated water that did not meet water quality standards.
Drinking water
Drinking water is water that is used in drink or food preparation; potable water is water that is safe to be used as drinking water. The amount of drinking water required to maintain good health varies, and depends on physical activity level, a ...
quality in the U.S. is
regulated by state and federal laws and codes, which set
maximum contaminant levels (MCLs) and Treatment Technique requirements for some pollutants and naturally occurring constituents, determine various operational requirements, require public notification for violation of standards, provide guidance to state primacy agencies, and require utilities to publish ''Consumer Confidence Reports.''
There are many chemicals and substances for which there are no regulatory standards applicable to drinking water utilities. EPA operates an ongoing research program to analyze various substances and consider whether additional standards are needed.
Background
In early US history, drinking water quality in the country was managed by individual drinking water utilities and at the state and local level. In 1914 the U.S.
Public Health Service
In public relations and communication science, publics are groups of individual people, and the public (a.k.a. the general public) is the totality of such groupings. This is a different concept to the sociological concept of the ''Öffentlichkei ...
(PHS) published a set of drinking water standards, pursuant to existing federal authority to regulate
interstate commerce
The Commerce Clause describes an enumerated power listed in the United States Constitution ( Article I, Section 8, Clause 3). The clause states that the United States Congress shall have power "to regulate Commerce with foreign Nations, and amo ...
, and in response to the 1893 ''Interstate Quarantine Act.'' As such the standards were directly applicable only to interstate
common carrier
A common carrier in common law countries (corresponding to a public carrier in some civil law systems,Encyclopædia Britannica CD 2000 "Civil-law public carrier" from "carriage of goods" usually called simply a ''carrier'') is a person or compan ...
s such as railroads. For local drinking water utilities, these standards were basically recommendations and not enforceable requirements. However, many municipal utilities began to voluntarily adopt the standards.
Ultimately the PHS standards were adopted and expanded as national drinking water standards after passage of the 1974
Safe Drinking Water Act
The Safe Drinking Water Act (SDWA) is the principal federal law in the United States intended to ensure safe drinking water for the public. Pursuant to the act, the Environmental Protection Agency (EPA) is required to set standards for drinking wa ...
(SDWA), and U.S. water quality became subject to a whole new generation of federal standards.
Enforcement of standards
The SDWA requires EPA to issue federal regulations for
public water systems. There are no federal regulations covering private drinking water wells, although some state and local governments have issued rules for these wells.
EPA enters into primary enforcement authority (primacy) agreements with state governments, so in most states EPA does not directly enforce the SDWA. State rules can be different from EPA's, but they must be at least as stringent.
EPA defines a public water system (PWS) as an entity that provides water for human consumption to at least 25 people (or at least 15 connections) for at least 60 days a year. There are three types of public water system: community systems (like cities or trailer parks); non-transient, non-community systems (like factories or schools with their own water source); and transient non-community systems (like rural restaurants or camps).
Enforcement of drinking water standards in small water systems is less consistent than enforcement in large systems. As of 2016 more than 3/4ths of small community water systems that were classified as having serious health violations by EPA still had the same violations three years later. Some violations included an overabundance of
lead
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
, exceeding allowed rates for
nitrate and
fecal coliform
A fecal coliform (British: faecal coliform) is a facultatively anaerobic, rod-shaped, gram-negative, non-sporulating bacterium. Coliform bacteria generally originate in the intestines of warm-blooded animals. Fecal coliforms are capable of growth ...
. Around half of the most contaminated water systems were located in
Kansas
Kansas () is a state in the Midwestern United States. Its capital is Topeka, and its largest city is Wichita. Kansas is a landlocked state bordered by Nebraska to the north; Missouri to the east; Oklahoma to the south; and Colorado to th ...
,
Texas
Texas (, ; Spanish: ''Texas'', ''Tejas'') is a state in the South Central region of the United States. At 268,596 square miles (695,662 km2), and with more than 29.1 million residents in 2020, it is the second-largest U.S. state by ...
and
Puerto Rico
Puerto Rico (; abbreviated PR; tnq, Boriken, ''Borinquen''), officially the Commonwealth of Puerto Rico ( es, link=yes, Estado Libre Asociado de Puerto Rico, lit=Free Associated State of Puerto Rico), is a Caribbean island and unincorporated ...
.
EPA's
Office of Enforcement and Compliance Assurance
The Office of Enforcement and Compliance Assurance (OECA) is the law enforcement arm of the United States Environmental Protection Agency (EPA). It is made up of attorneys, special agents, scientists and other employees.
Organization
The OECA ...
noted that the agency faced "a daunting list of challenges" in its continuing efforts, particularly with small systems that "lack the basic infrastructure, resources and capacity to provide clean drinking water."
Consumer Confidence Reports
EPA's ''Consumer Confidence Rule'' of 1998 requires community public water suppliers to provide customers with annual reports of drinking water quality, called ''Consumer Confidence Reports'' (CCR). 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.
The regulation requires water suppliers to list the water sources, report detected contaminants and the system's compliance with
National Primary Drinking Water Regulations in the annual reports. Suppliers may also provide additional information such as explanation of the system's
treatment processes, advice on
water conservation
Water conservation includes all the policies, strategies and activities to sustainably manage the natural resource of fresh water, to protect the hydrosphere, and to meet the current and future human demand (thus avoiding water scarcity). Popula ...
and information about protecting the community's water sources.
Common drinking water contaminants
Studies have shown that there can be more than 80 common contaminants in treated drinking water that may pose a risk to human health. These contaminants fall into two separate categories, acute and chronic effects.
* Acute effects occur within hours or days of the time that a person consumes a contaminant.
People can experience acute health effects from almost any contaminant if they are exposed to extraordinarily high levels (as in the case of a spill). In drinking water, microbes, such as bacteria and viruses, are the contaminants with the greatest chance of reaching levels high enough to cause acute health effects. Acute effects contaminants are the most commons type that are found in drinking water. Acute contaminants are usually easy for the human body to fight off and don't normally have long lasting health effects.
* Chronic effects occur after people consume a contaminant at levels over EPA's safety standards over the course of many years.
The drinking water contaminants that can have chronic effects include chemicals (such as disinfection byproducts, solvents and pesticides), radionuclides (such as radium), and minerals (such as arsenic). Examples of these chronic effects include cancer, liver or kidney problems, or reproductive difficulties.
Though these chronic contaminants are rare in the US, there are many parts of the world that battle with these chronic contaminants and have to face the possible hazards on a daily basis. A few common water-borne contaminants include aluminum, ammonia, arsenic, barium, cadmium, chloramine, chromium, copper, fluoride, bacteria and viruses, lead, nitrates and nitrites, mercury, perchlorate, radium, selenium, silver, and uranium. Some of these contaminants are easy to detect through human senses, such as smell and taste, and other contaminants are impossible to detect with the human eye. Some of the most dangerous contaminants are consumed without any notice. It is extremely important to know the difference between chemical and biological contaminants. Chemical contaminants are elements or compounds that can either be naturally occurring or man-made. These contaminants usually result in external/internal damages to the body. Biological contaminants are organisms that are found in water these contaminates include viruses and bacteria and are usually fought off by the bodies immune system.
Substances for which there are federal standards
As of 2019 EPA has promulgated 88 standards for microorganisms, chemicals and radionuclides. The standards are organized into six groups:
* Microorganisms
* Disinfectants
* Disinfection byproducts
* Inorganic chemicals
* Organic chemicals
* Radionuclides.
Microorganisms
EPA has issued standards for ''
Cryptosporidium,'' ''
Giardia lamblia
''Giardia duodenalis'', also known as ''Giardia intestinalis'' and ''Giardia lamblia'', is a flagellated parasitic microorganism of the genus '' Giardia'' that colonizes the small intestine, causing a diarrheal condition known as giardiasis. ...
,'' ''
Legionella
''Legionella'' is a genus of pathogenic gram-negative bacteria that includes the species '' L. pneumophila'', causing legionellosis (all illnesses caused by ''Legionella'') including a pneumonia-type illness called Legionnaires' disease and a mil ...
,''
coliform bacteria
Coliform bacteria are defined as either motile or non-motile Gram-negative non- spore forming Bacilli that possess β-galactosidase to produce acids and gases under their optimal growth temperature of 35-37°C. They can be aerobes or facultative ...
and
enteric viruses. EPA also requires two microorganism-related tests to indicate water quality:
plate count and
turbidity
Turbidity is the cloudiness or haziness of a fluid caused by large numbers of individual particles that are generally invisible to the naked eye, similar to smoke in air. The measurement of turbidity is a key test of water quality.
Fluids ...
.
''Cryptosporidium''
''Cryptosporidium'' is a parasite that has a thick outer shell and thus is highly resistant to disinfection with
chlorine
Chlorine is a chemical element with the symbol Cl and atomic number 17. The second-lightest of the halogens, it appears between fluorine and bromine in the periodic table and its properties are mostly intermediate between them. Chlorine i ...
. 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, sometimes informally called crypto, is a parasitic disease caused by '' Cryptosporidium'', a genus of protozoan parasites in the phylum Apicomplexa. It affects the distal small intestine and can affect the respiratory tra ...
in the U.S. have been associated with contaminated drinking water, including a well-publicized one in
Milwaukee, Wisconsin
Milwaukee ( ), officially the City of Milwaukee, is both the most populous and most densely populated city in the U.S. state of Wisconsin and the county seat of Milwaukee County, Wisconsin, Milwaukee County. With a population of 577,222 at th ...
in 1993.
The
Long Term 2 Enhanced Surface Water Treatment Rule The Long Term 2 Enhanced Surface Water Treatment Rule ("LT2ESWTR" or simply "LT2") is a 2006 regulation promulgated by the United States Environmental Protection Agency (EPA) pursuant to the Safe Drinking Water Act. The rule required public water sy ...
("LT2 rule") of 2006 requires evaluation of surface water treatment plants and that these plants take specific actions to minimize the potential for ''Cryptosporidium'' infections.
Disinfectants
The EPA has released standards for many chemicals including disinfectants used to treat drinking water under the SDWA. Germs can contaminate water which puts public health at risk including carrying disease causing germs such as ''
Salmonella'', ''
Campylobacter'', and
norovirus
Norovirus, sometimes referred to as the winter vomiting disease, is the most common cause of gastroenteritis. Infection is characterized by non-bloody diarrhea, vomiting, and stomach pain. Fever or headaches may also occur. Symptoms usually devel ...
. These germs are killed off through a disinfect process that is usually done with chlorine or
chloramine
Chloramines refer to derivatives of ammonia and organic amines wherein one or more N-H bonds have been replaced by N-Cl bonds. Two classes of compounds are considered: inorganic chloramines and organic chloramines.
Inorganic chloramines
Inorgan ...
. Disinfection with chlorine is called chlorination and disinfection with chloramine is called chloramination. Both of these processes include disinfecting the water by adding the chemicals to it which is meant to destroy any germs or bacteria that came in contact with the water. A PWS may alternate the use of chlorine and chloramine in order to decrease the risk of biofilm in its pipes. Chlorine and chloramine are allowed at a level of up to 4 milligrams per liter (mg/L) or 4 parts per million (ppm) in drinking water. However, federal standards includes antimicrobials and any pesticide products and devices that make antimicrobial claims. Products that make such claims must be registered under the EPA before use and distribution. EPA has issued standards for chlorine,
monochloramine
Monochloramine, often called chloramine, is the chemical compound with the formula NH2Cl. Together with dichloramine (NHCl2) and nitrogen trichloride (NCl3), it is one of the three chloramines of ammonia. It is a colorless liquid at its melting p ...
,
chlorine dioxide
Chlorine dioxide is a chemical compound with the formula ClO2 that exists as yellowish-green gas above 11 °C, a reddish-brown liquid between 11 °C and −59 °C, and as bright orange crystals below −59 °C. It is usually ...
,
ozone disinfection and
ultraviolet germicidal irradiation
Ultraviolet germicidal irradiation (UVGI) is a disinfection method that uses short-wavelength ultraviolet (ultraviolet C or UV-C) light to kill or inactivate microorganisms by destroying nucleic acids and disrupting their DNA, leaving them unabl ...
(UV).
Disinfection by-products
EPA has issued standards for
bromate
The bromate anion, BrO, is a bromine-based oxoanion. A bromate is a chemical compound that contains this ion. Examples of bromates include sodium bromate, (), and potassium bromate, ().
Bromates are formed many different ways in municipal drin ...
,
chlorite,
haloacetic acids Haloacetic acids are carboxylic acids in which a halogen atom takes the place of a hydrogen atom in acetic acid. Thus, in a monohaloacetic acid, a single halogen would replace a hydrogen atom. For example, chloroacetic acid would have the structur ...
and
trihalomethane
In chemistry, trihalomethanes (THMs) are chemical compounds in which three of the four hydrogen atoms of methane () are replaced by halogen atoms. Many trihalomethanes find uses in industry as solvents or refrigerants. THMs are also environmenta ...
s.
Disinfectants such as chlorine can react with natural material in the water to form disinfection byproducts such as trihalomethanes. Animal studies indicate that none of the chlorination byproducts studied to date is a potent carcinogen at concentrations normally found in drinking water. According to the "GreenFacts" website, there is insufficient
epidemiological
Epidemiology is the study and analysis of the distribution (who, when, and where), patterns and determinants of health and disease conditions in a defined population.
It is a cornerstone of public health, and shapes policy decisions and evidenc ...
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.
Inorganic chemicals
EPA has issued standards for
antimony
Antimony is a chemical element with the symbol Sb (from la, stibium) and atomic number 51. A lustrous gray metalloid, it is found in nature mainly as the sulfide mineral stibnite (Sb2S3). Antimony compounds have been known since ancient t ...
,
arsenic
Arsenic is a chemical element with the symbol As and atomic number 33. Arsenic occurs in many minerals, usually in combination with sulfur and metals, but also as a pure elemental crystal. Arsenic is a metalloid. It has various allotropes, ...
,
asbestos,
barium,
beryllium
Beryllium is a chemical element with the symbol Be and atomic number 4. It is a steel-gray, strong, lightweight and brittle alkaline earth metal. It is a divalent element that occurs naturally only in combination with other elements to form m ...
,
cadmium
Cadmium is a chemical element with the symbol Cd and atomic number 48. This soft, silvery-white metal is chemically similar to the two other stable metals in group 12, zinc and mercury. Like zinc, it demonstrates oxidation state +2 in most of ...
,
chromium,
copper
Copper is a chemical element with the symbol Cu (from la, cuprum) and atomic number 29. It is a soft, malleable, and ductile metal with very high thermal and electrical conductivity. A freshly exposed surface of pure copper has a pinkis ...
,
cyanide
Cyanide is a naturally occurring, rapidly acting, toxic chemical that can exist in many different forms.
In chemistry, a cyanide () is a chemical compound that contains a functional group. This group, known as the cyano group, consists of ...
,
fluoride,
lead
Lead is a chemical element with the symbol Pb (from the Latin ) and atomic number 82. It is a heavy metal that is denser than most common materials. Lead is soft and malleable, and also has a relatively low melting point. When freshly cu ...
,
mercury,
nitrate,
nitrite,
selenium
Selenium is a chemical element with the symbol Se and atomic number 34. It is a nonmetal (more rarely considered a metalloid) with properties that are intermediate between the elements above and below in the periodic table, sulfur and tellurium, ...
and
thallium
Thallium is a chemical element with the symbol Tl and atomic number 81. It is a gray post-transition metal that is not found free in nature. When isolated, thallium resembles tin, but discolors when exposed to air. Chemists William Crookes an ...
.
Fluoride
Most people associate fluoride with the practice of intentionally adding fluoride to public drinking-water supplies for the prevention of
tooth decay
Tooth decay, also known as cavities or caries, is the breakdown of teeth due to acids produced by bacteria. The cavities may be a number of different colors from yellow to black. Symptoms may include pain and difficulty with eating. Complicatio ...
. 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 National Research Council may refer to:
* National Research Council (Canada), sponsoring research and development
* National Research Council (Italy), scientific and technological research, Rome
* National Research Council (United States), part of ...
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 is one of the four major tissues that make up the tooth in humans and many other animals, including some species of fish. It makes up the normally visible part of the tooth, covering the crown. The other major tissues are dentin, ...
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. For example, the fluoride MCL for public water systems in
New York (state)
New York, officially the State of New York, is a state in the Northeastern United States. It is often called New York State to distinguish it from its largest city, New York City. With a total area of , New York is the 27th-largest U.S. stat ...
is 2.2 mg/L.
Lead
Lead typically gets into drinking water after the water leaves the treatment plant. The source of lead is most likely pipe or
solder
Solder (; NA: ) is a fusible metal alloy used to create a permanent bond between metal workpieces. Solder is melted in order to wet the parts of the joint, where it adheres to and connects the pieces after cooling. Metals or alloys suitable ...
in older service connections or older plumbing inside homes, from which lead "leaks" into the water through corrosion. The symptoms of lead poisoning may include abdominal pain,
constipation
Constipation is a bowel dysfunction that makes bowel movements infrequent or hard to pass. The stool is often hard and dry. Other symptoms may include abdominal pain, bloating, and feeling as if one has not completely passed the bowel movement ...
, headaches, ADHD (Attention Deficit Hyperactivity Disorder), irritability, memory problems,
inability to have children, and
tingling
Paresthesia is an abnormal sensation of the skin (tingling, pricking, chilling, burning, numbness) with no apparent physical cause. Paresthesia may be transient or chronic, and may have any of dozens of possible underlying causes. Paresthesias ar ...
in the hands and feet.
It causes almost 10% of
intellectual disability
Intellectual disability (ID), also known as general learning disability in the United Kingdom and formerly mental retardation, Rosa's Law, Pub. L. 111-256124 Stat. 2643(2010). is a generalized neurodevelopmental disorder characterized by signif ...
of otherwise unknown cause and can result in behavioral problems.
Some of the effects are permanent.
[ In severe cases ]anemia
Anemia or anaemia (British English) is a blood disorder in which the blood has a reduced ability to carry oxygen due to a lower than normal number of red blood cells, or a reduction in the amount of hemoglobin. When anemia comes on slowly, t ...
, seizures
An epileptic seizure, informally known as a seizure, is a period of symptoms due to abnormally excessive or synchronous neuronal activity in the brain. Outward effects vary from uncontrolled shaking movements involving much of the body with l ...
, coma, or death
Death is the irreversible cessation of all biological functions that sustain an organism. For organisms with a brain, death can also be defined as the irreversible cessation of functioning of the whole brain, including brainstem, and brain ...
may occur.[
EPA's ]Lead and Copper Rule
The Lead and Copper Rule (LCR) is a United States federal regulation that limits the concentration of lead and copper allowed in public drinking water at the consumer's tap, as well as limiting the permissible amount of pipe corrosion occurring ...
(LCR), first published in 1991, defines an "action level" of 15 parts per billion (ppb) for lead, which is different than a maximum contaminant level. Under the LCR, if tests show that the level of lead in 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".
A typical utility action is to adjust the chemistry of the drinking water with anti-corrosive additives, but replacement of customer pipes is also an option. Most communities have avoided customer pipe replacement due to the high cost. Some water systems have undertaken programs to remove all lead service lines, especially after the publicity surrounding the Flint, Michigan water crisis in 2016. In 2018, NPR reported that about 180 towns were operating removal programs using financing from federal, state, or local taxpayers, other water customers, and charitable donations to provide grants or loans to property owners to cover the cost of removal. This includes systems in Boston (Massachusetts Water Resources Authority
The Massachusetts Water Resources Authority (MWRA) is a public authority in the Commonwealth of Massachusetts that provides wholesale drinking water and sewage services to certain municipalities and industrial users in the state, primarily in th ...
), Cincinnati (Greater Cincinnati Water Works), Gary ( Indiana American Water), Detroit ( Detroit Water and Sewerage Department), and Lansing
Lansing () is the capital of the U.S. state of Michigan. It is mostly in Ingham County, although portions of the city extend west into Eaton County and north into Clinton County. The 2020 census placed the city's population at 112,644, makin ...
. Madison, Wisconsin
Madison is the county seat of Dane County and the capital city of the U.S. state of Wisconsin. As of the 2020 census the population was 269,840, making it the second-largest city in Wisconsin by population, after Milwaukee, and the 80th-lar ...
removed all of its lead service pipes over an 11-year period, starting in 2001.
In Washington, DC
)
, image_skyline =
, image_caption = Clockwise from top left: the Washington Monument and Lincoln Memorial on the National Mall, United States Capitol, Logan Circle, Jefferson Memorial, White House, Adams Morgan ...
a pipe replacement program began in 2004 to replace lead service connection
A lead service line (LSL, also known as lead service pipe, and lead connection pipe) is a pipe made of lead which is used in potable water distribution to connect a water main to a user's premises.
Lead exposure is a public health hazard as it cau ...
s to about 35,000 homes. The effectiveness of the program was questioned in 2008 by DC Water
The District of Columbia Water and Sewer Authority (DC Water) provides drinking water, sewage collection and sewage treatment for the District of Columbia, in the United States. The utility also provides wholesale wastewater treatment services ...
, the city's utility. In 2016, more than 5,000 drinking water systems were found to be in violation of the lead and copper rule.
In response to the Flint water crisis, EPA published revisions to the LCR on January 15, 2021, addressing testing, pipe replacement and related issues. The rule mandates additional requirements for sampling tap water, corrosion control, public outreach and testing water in schools. The rule continues the requirement for replacement of lead service line
A lead service line (LSL, also known as lead service pipe, and lead connection pipe) is a pipe made of lead which is used in potable water distribution to connect a water main to a user's premises.
Lead exposure is a public health hazard as it cau ...
s when the action level for lead is exceeded, but requires that a utility replace at least 3 percent of its lines annually, compared to 7 percent under the prior regulation. Several citizen and environmental groups immediately filed lawsuits challenging the rule.
Other incidents of widespread lead contamination include the Pittsburgh water crisis
The Pittsburgh water crisis arose from a substantial increase in the lead concentration of the city's water supply. Although catalyzed by the hiring of cost-cutting water consultancy Veolia in 2012, and an unauthorized change of anti-erosion chemi ...
(started in 2014, discovered in 2016, ongoing in 2018) and the Newark water crisis
The Newark, New Jersey water crisis began in 2016 when elevated lead levels were observed in multiple Newark Public Schools district schools throughout the city.
Multiple water studies were conducted by both federal agencies, such as the United ...
(in schools, 2016–2019).
Congress passed the ''Reduction of Lead in Drinking Water Act'' in 2011. This amendment to the SDWA, effective in 2014, tightened the definition of "lead-free" plumbing fixtures and fittings. EPA published a final rule implementing the amendment on September 1, 2020.
In 2021, President Joe Biden's federal $2.3 trillion American Jobs Plan
The Build Back Better Plan or Build Back Better agenda was a legislative framework proposed by U.S. president Joe Biden between 2020 and 2021. Generally viewed as ambitious in size and scope, and even after it was reduced in size, it became the ...
proposed spending $45 billion on lead pipe removal, which is the estimated cost of removing all remaining lead pipes nationwide. Bipartisan negotiations reduced this to $15 billion in the Infrastructure Investment and Jobs Act
The Infrastructure Investment and Jobs Act (IIJA), also known as the Bipartisan Infrastructure Bill and originally in the House as the INVEST in America ActH.R. 3684, is a United States federal statute enacted by the 117th United States Congress ...
, which contained only $550 billion in new spending. $11 billion in the bill allocated generally to drinking water infrastructure could also be spent on led pipe removal.
Chromium
EPA published standards in 1991 to ensure that total chromium is limited to 0.1 milligrams per liter or 100 parts per billion in drinking water. It is an odorless and tasteless metal that can be naturally occurring in rocks, plants, soil and volcanic dust, and animals. It can also be introduced to the environment through man made processes such erosion of natural chromium deposits, leakage, poor storage, or inadequate industrial waste disposal practices. In large doses human consumption or exposure can lead to adverse health effects including cancer, eye, stomach, and respiratory tract issues. An example of this chemical causing adverse health issues is through a well-known hexavalent chromium
Hexavalent chromium (chromium(VI), Cr(VI), chromium 6) is chromium in any chemical compound that contains the element in the +6 oxidation state (thus hexavalent). Virtually all chromium ore is processed via hexavalent chromium, specifically the ...
(chromium 6) pollution event in Hinkley, California. Groundwater contamination in Hinkley was caused by water containing hexavalent chromium being dumped on the ground by Pacific Gas and Electric
The Pacific Gas and Electric Company (PG&E) is an American investor-owned utility (IOU). The company is headquartered in the Pacific Gas & Electric Building, in San Francisco, California. PG&E provides natural gas and electricity to 5.2 milli ...
(PG&E) from 1952 to 1966. PG&E used this chemical to deter corrosion in their cooling towers. The use of this chemical in cooling towers lead to a wastewater leakage into unlined ponds at their cooling tower sites. This, in turn, turned into groundwater contamination which adversely affected the town of Hinkley. The contamination resulted in a $333 million settlement in 1996. The clean-up process is ongoing as of 2022, with monthly monitoring reports submitted by PG&E. This case has led to California being the only state in the US to adopt an MCL of 10 ppb specifically for hexavalent chromium instead of relying on an overall total chromium count.
Organic chemicals
EPA has issued standards for 53 organic compounds, including benzene
Benzene is an organic chemical compound with the molecular formula C6H6. The benzene molecule is composed of six carbon atoms joined in a planar ring with one hydrogen atom attached to each. Because it contains only carbon and hydrogen atoms ...
, dioxin ( 2,3,7,8-TCDD), PCBs
Polychlorinated biphenyls (PCBs) are highly carcinogenic chemical compounds, formerly used in industrial and consumer products, whose production was banned in the United States by the Toxic Substances Control Act in 1979 and internationally by t ...
, styrene
Styrene () is an organic compound with the chemical formula C6H5CH=CH2. This derivative of benzene is a colorless oily liquid, although aged samples can appear yellowish. The compound evaporates easily and has a sweet smell, although high concen ...
, toluene
Toluene (), also known as toluol (), is a substituted aromatic hydrocarbon. It is a colorless, water-insoluble liquid with the smell associated with paint thinners. It is a mono-substituted benzene derivative, consisting of a methyl group (CH3) a ...
, vinyl chloride
Vinyl chloride is an organochloride with the formula H2C=CHCl. It is also called vinyl chloride monomer (VCM) or chloroethene. This colorless compound is an important industrial chemical chiefly used to produce the polymer polyvinyl chloride (PVC ...
and several pesticides. The presence of organic chemicals in water can cause an issues for human health and adverse effects on the environment will occur. This is especially because processes such as disinfection by chlorine can cause toxic chemical reactions to occur and leak out into the surrounding area. Some sources of these organic chemicals include pesticides and herbicides, polychlorinatedbyphenlys, industrial/commercial organics, and disinfection by products. Organic chemicals can be characterized in 2 categories: volatile organic compound
Volatile organic compounds (VOCs) are organic compounds that have a high vapour pressure at room temperature. High vapor pressure correlates with a low boiling point, which relates to the number of the sample's molecules in the surrounding air, a ...
s (VOCs), and synthetic organic contaminants (SOCs). VOCs and SOCs do not reside naturally in drinking water, and are detected when they are improperly stored or leaked into water systems through contamination.
Radionuclides
Radionuclides are reactive forms of elements that can be present in drinking water either through man made or natural processes. Every radionuclide has its own half life therefore has its own specific rate of measurement before decaying. There are some radionuclides that decay in seconds while others takes millions of years. Once it decays radionuclides turn into radioisotopes. This process emits radiation. Exposure to radiation to lead to acute and chronic consequences for human health including radiation sickness, cancer, and cardiovascular disease. The EPA has issued standards for alpha particle
Alpha particles, also called alpha rays or alpha radiation, consist of two protons and two neutrons bound together into a particle identical to a helium-4 nucleus. They are generally produced in the process of alpha decay, but may also be pr ...
s, beta particles and photon
A photon () is an elementary particle that is a quantum of the electromagnetic field, including electromagnetic radiation such as light and radio waves, and the force carrier for the electromagnetic force. Photons are massless, so they a ...
emitters, radium
Radium is a chemical element with the symbol Ra and atomic number 88. It is the sixth element in group 2 of the periodic table, also known as the alkaline earth metals. Pure radium is silvery-white, but it readily reacts with nitrogen (rathe ...
and uranium
Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...
. There is a combined standard of 4 mrem/year for beta emitters, a gross alpha standard for all alphas of 15 pCi/L, and a combined radium 226/228 of 5 pCi/L. Uranium and radium are given a different standard of 30 µg/L. The regulation of radionuclides began in 1977 and updated in 2000 to ensure that the maximum contaminant levels (MCL) are met according to the Radionuclides Rule in the state and public water systems.
Substances for which there are no federal standards
EPA maintains the '' Contaminant Candidate List'' (CCL), a list of substances which are being considered for possible regulation in the federal drinking water program. In an effort to assess the importance of certain substances as contaminants, the National Primary Drinking Water Regulations have required some public water systems to monitor for some of those substances.
Unregulated contaminant monitoring
The unregulated contaminant monitoring program keeps track of whether or not certain chemicals are present in PWS and at what level. EPA stores the monitoring data submitted by the PWS in a National Contaminant Occurrence Database, and considers the data in the development of CCLs and future regulations.
EPA published its Fifth Unregulated Contaminant Monitoring Rule in December 2021. A sample of very small PWS (serving less than 3,000 people), and all larger systems are required to monitor for 29 perfluorinated alkylated substances
Per- and polyfluoroalkyl substances (PFASs) are synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. An early definition, from 2011, required that they contain at least one perfluoroalkyl m ...
(PFAS) and lithium between January 2023 through December 2025.
Perfluorinated alkylated substances
Perfluorooctanoic acid
Perfluorooctanoic acid (PFOA; conjugate base perfluorooctanoate; also known colloquially as C8, for its 8 carbon chain structure) is a perfluorinated carboxylic acid produced and used worldwide as an industrial surfactant in chemical processes a ...
(PFOA) is a synthetic perfluorinated carboxylic acid
Perfluoroalkyl carboxylic acids (PFCAs), or perfluorocarboxylic acids are compounds of the formula CnF(2n+1)CO2H that belong to the class of per- and polyfluoroalkyl substances. The simplest example is trifluoroacetic acid. These compounds are o ...
and fluorosurfactant
Per- and polyfluoroalkyl substances (PFASs) are synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. An early definition, from 2011, required that they contain at least one perfluoroalkyl mo ...
. It has been used in the manufacture of such prominent consumer goods as polytetrafluoroethylene (PTFE; Teflon
Polytetrafluoroethylene (PTFE) is a synthetic fluoropolymer of tetrafluoroethylene that has numerous applications. It is one of the best-known and widely applied PFAS. The commonly known brand name of PTFE-based composition is Teflon by Chemo ...
and similar products). PFOA has been manufactured since the 1940s in industrial quantities. PFOA persists indefinitely in the environment. It is a toxicant
A toxicant is any toxic substance, whether man-made or naturally occurring. By contrast, a toxin is a poison produced naturally by an organism (e.g. plant, animal, insect). The different types of toxicants can be found in the air, soil, water, or ...
and carcinogen
A carcinogen is any substance, radionuclide, or radiation that promotes carcinogenesis (the formation of cancer). This may be due to the ability to damage the genome or to the disruption of cellular metabolic processes. Several radioactive subs ...
in animals. PFOA has been detected in the blood of more than 98% of the general US population in the low and sub-parts per billion
In science and engineering, the parts-per notation is a set of pseudo-units to describe small values of miscellaneous dimensionless quantities, e.g. mole fraction or mass fraction. Since these fractions are quantity-per-quantity measures, they ...
(ppb) range, and levels are higher in chemical plant employees and surrounding subpopulations.
In the United States there are no federal drinking water standards for PFOA, PFOS
Perfluorooctanesulfonic acid (PFOS) (conjugate base perfluorooctanesulfonate) is a chemical compound having an eight-carbon fluorocarbon chain and a sulfonic acid functional group and thus a perfluorosulfonic acid. It is an anthropogenic (man ...
or PFNA
Perfluorononanoic acid, or PFNA, is a synthetic perfluorinated carboxylic acid and fluorosurfactant that is also an environmental contaminant found in people and wildlife along with PFOS and PFOA.
Chemistry and properties
In acidic form it is a ...
(collectively referred to as perfluorinated alkylated substances
Per- and polyfluoroalkyl substances (PFASs) are synthetic organofluorine chemical compounds that have multiple fluorine atoms attached to an alkyl chain. An early definition, from 2011, required that they contain at least one perfluoroalkyl m ...
or PFAS) as of 2022. EPA began requiring public water systems to monitor for PFOA and PFOS in 2012, and published drinking water health advisories, which are non-regulatory technical documents, in 2016. In March 2021 EPA announced that it would develop regulations for PFOA and PFOS.[EPA (2021-03-03). "Announcement of Final Regulatory Determinations for Contaminants on the Fourth Drinking Water Contaminant Candidate List." ''Federal Register,'' ]
In November 2017 the New Jersey Department of Environmental Protection
The New Jersey Department of Environmental Protection (NJDEP) is a government agency in the U.S. state of New Jersey that is responsible for managing the state's natural resources and addressing issues related to pollution. NJDEP now has a staff ...
announced plans to develop its own drinking water standards for PFOA. New Jersey published a standard for PFNA in September 2018, the first state to do so. The state set the MCL at 13 parts per trillion (ppt). Other states that have issued PFAS standards include Michigan
Michigan () is a U.S. state, state in the Great Lakes region, Great Lakes region of the Upper Midwest, upper Midwestern United States. With a population of nearly 10.12 million and an area of nearly , Michigan is the List of U.S. states and ...
, New York and Vermont
Vermont () is a state in the northeast New England region of the United States. Vermont is bordered by the states of Massachusetts to the south, New Hampshire to the east, and New York to the west, and the Canadian province of Quebec to ...
.
MTBE
Methyl tert-butyl ether
Methyl ''tertiary''-butyl ether (MTBE), also known as methyl tert-butyl ether and ''tert''-butyl methyl ether, is an organic compound with a structural formula (CH3)3COCH3. MTBE is a volatile, flammable, and colorless liquid that is sparingly sol ...
(MTBE) is used as a gasoline additive, as well as in various industrial manufacturing processes. The compound has contaminated groundwater and soil across the U.S., and its use has been banned in some states, including California and New York. (''See'' MTBE controversy.) EPA included MTBE on its first Contaminant Candidate List, published in 1998, but has not announced whether it will develop a regulation.
Perchlorate
Perchlorate
A perchlorate is a chemical compound containing the perchlorate ion, . The majority of perchlorates are commercially produced salts. They are mainly used as oxidizers for pyrotechnic devices and to control static electricity in food packaging. Per ...
has 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 perchlorate alters the production of thyroid
The thyroid, or thyroid gland, is an endocrine gland in vertebrates. In humans it is in the neck and consists of two connected lobes. The lower two thirds of the lobes are connected by a thin band of tissue called the thyroid isthmus. The thy ...
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 fertilizer
A fertilizer (American English) or fertiliser (British English; see spelling differences) is any material of natural or synthetic origin that is applied to soil or to plant tissues to supply plant nutrients. Fertilizers may be distinct from ...
s 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 perchlorate 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 seventy 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 2004 eight states had non-binding advisories for perchlorate in drinking water, ranging from 1 to 18 ppb. Only two states—Massachusetts
Massachusetts (Massachusett: ''Muhsachuweesut Massachusett_writing_systems.html" ;"title="nowiki/> məhswatʃəwiːsət.html" ;"title="Massachusett writing systems">məhswatʃəwiːsət">Massachusett writing systems">məhswatʃəwiːsət'' En ...
and California
California is a state in the Western United States, located along the Pacific Coast. With nearly 39.2million residents across a total area of approximately , it is the most populous U.S. state and the 3rd largest by area. It is also the m ...
—set legally binding maximum contaminant levels on the allowable amount of perchlorate in drinking water, at 2 ppb and 6 ppb respectively.
EPA issued an "Interim Health Advisory" for perchlorate in 2009, while it continued to evaluate whether to issue regulatory standards. In 2011 the agency announced that it would develop regulations for perchlorate. Following a 2016 consent decree issued by a federal district court
The United States district courts are the trial courts of the U.S. federal judiciary. There is one district court for each federal judicial district, which each cover one U.S. state or, in some cases, a portion of a state. Each district cou ...
in New York, EPA published a proposed rule on June 26, 2019, with a proposed maximum contaminant level of 0.056 mg/L for public water systems.
On June 18, 2020, EPA announced that it was withdrawing its 2019 proposal and its 2011 regulatory determination, stating that it had taken "proactive steps" with state and local governments to address perchlorate contamination. In September 2020 the Natural Resources Defense Council
The Natural Resources Defense Council (NRDC) is a United States-based 501(c)(3) non-profit international environmental advocacy group, with its headquarters in New York City and offices in Washington D.C., San Francisco, Los Angeles, Chicago, Bo ...
(NRDC) filed suit against EPA for its failure to regulate perchlorate. NRDC stated that the chemical has now been detected in 26 states, and that 26 million people may be affected by perchlorate in their drinking water.
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 Press
The Associated Press (AP) is an American non-profit news agency headquartered in New York City. Founded in 1846, it operates as a cooperative, unincorporated association. It produces news reports that are distributed to its members, U.S. ne ...
published in March 2008. 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. In 2010 EPA stated that "Further research suggests that certain drugs may cause ecological harm...To date, scientists have found no evidence of adverse human health effects from PPCPs in the environment."
Radon
EPA proposed regulations for radon
Radon is a chemical element with the symbol Rn and atomic number 86. It is a radioactive, colourless, odourless, tasteless noble gas. It occurs naturally in minute quantities as an intermediate step in the normal radioactive decay chains through ...
in 1991 and 1999. In 2010 it was reported that EPA had not finalized the proposal due to concerns raised by some utilities about high costs for controlling radon. However, nine states had issued their own radon guidelines.
Water quality of private wells
Approximately 13 million households in the US get their drinking water from privately owned wells. Private wells are not regulated by EPA. In general, private well owners are responsible for testing their wells, and some states provide guidance and technical assistance on testing.
A 2020 study found that children raised in homes with unregulated wells had a 25% increased risk of elevated blood lead than children raised in homes supplied by water utilities regulated by the SDWA.
See also
* 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 (SDWA) is the principal fed ...
* Water quality
Water quality refers to the chemical, physical, and biological characteristics of water based on the standards of its usage. It is most frequently used by reference to a set of standards against which compliance, generally achieved through tr ...
(ambient/environmental)
* Water supply and sanitation in the United States
Water supply and sanitation in the United States involves a number of issues including water scarcity, pollution, a backlog of investment, concerns about the affordability of water for the poorest, and a rapidly retiring workforce. Increased var ...
References
{{Reflist
Further reading
EPA Alumni Association: Drinking Water, Half Century of Progress
– a brief history of U.S. efforts to protect drinking water
External links
- U.S. Centers for Disease Control and Prevention
Drinking Water from Forests and Grasslands: A Synthesis of the Scientific Literature
edited by George E. Dissmeyer, U.S. Forest Service (2000)
Environmental issues in the United States
Water supply and sanitation in the United States