Drinking water

Drinking water or potable water is water that is safe for ingestion, either when drunk directly in liquid form or consumed indirectly through food preparation. It is often (but not always) supplied through taps in which case it is also called tap water. Typically in developed countries, tap water meets drinking water quality standards, even though only a small proportion is actually consumed or used in food preparation. Other typical uses for tap water include washing, toilets, and irrigation. Greywater may also be used for toilets or irrigation. Its use for irrigation however may be associated with risks.[1]

Drinking water that is supplied through a tap (tap water).

The amount of drinking water required to maintain good health varies, and depends on physical activity level, age, health-related issues, and environmental conditions.[2][3] For those who work in a hot climate, up to 16 litres (4.2 US gal) a day may be required.[2]

Globally, by 2015, 89% of people had access to water from a source that is suitable for drinking – called improved water sources.[1] In sub-Saharan Africa, access to potable water ranged from 40% to 80% of the population. Nearly 4.2 billion people worldwide had access to tap water, while another 2.4 billion had access to wells or public taps.[1] The World Health Organization considers access to safe drinking-water a basic human right.

About 1 to 2 billion people lack safe drinking water.[4] Water can carry vectors of disease. More people die from unsafe water than from war, then-U.N. secretary-general Ban Ki-moon said in 2010.[5] Developing countries are most affected by unsafe drinking water.

Sources
Further information: Water resources and Water security
Drinking water vending machines in Thailand. One litre of potable water is sold (into the customer's own bottle) for 1 baht.
Diagram of water well types
Simplified diagram of a water supply network

Potable water is available in almost all populated areas of the Earth, although it may be expensive and the supply may not always be sustainable. Sources where drinking water is commonly obtained include springs, hyporheic zones and aquifers (groundwater), from rainwater harvesting, surface water (from rivers, streams, glaciers), or desalinated seawater.

For these water sources to be consumed safely, they must receive adequate water treatment and meet drinking water quality standards.[6]

An experimental source is atmospheric water generators.[7]

Springs are often used as sources for bottled waters.[8]

Supply
Main articles: Water supply and Water supply network

The most efficient and convenient way to transport and deliver potable water is through pipes. Plumbing can require significant capital investment. Some systems suffer high operating costs. The cost to replace the deteriorating water and sanitation infrastructure of industrialized countries may be as high as $200 billion a year. Leakage of untreated and treated water from pipes reduces access to water. Leakage rates of 50% are not uncommon in urban systems.[9]

Tap water, delivered by domestic water systems refers to water piped to homes and delivered to a tap or spigot.

Quantity

Usage for general household use
Further information: Water use and Residential water use in the U.S. and Canada

In the United States, the typical water consumption per capita, at home, is 69.3 US gallons (262 L; 57.7 imp gal) of water per day.[10][11] Of this, only 1% of the water provided by public water suppliers is for drinking and cooking.[12] Uses include (in decreasing order) toilets, washing machines, showers, baths, faucets, and leaks.

As of 2015, American households use an average of 300 gallons of water a day.[13]

Usage for drinking
This section is an excerpt from Daily consumption of drinking water.[edit]
The recommended amount of drinking water for human consumption per day is variable.[14] It depends on physical activity, age, health, and environmental conditions. In the United States, the Adequate Intake for total water, based on median intakes, is 3.7 litres (130 imp fl oz; 130 US fl oz) per day for human males older than 18, and 2.7 litres (95 imp fl oz; 91 US fl oz) per day for human females older than 18 which includes about 80% from beverages and 20% from food.[15] The European Food Safety Authority recommends 2.0 litres (70 imp fl oz; 68 US fl oz) of total water per day for adult women and 2.5 litres (88 imp fl oz; 85 US fl oz) per day for adult men.[16]

Animals

The qualitative and quantitative aspects of drinking water requirements on domesticated animals are studied and described within the context of animal husbandry. However, relatively few studies have been focused on the drinking behavior of wild animals.

Quality
Main articles: Water quality, Water pollution, and Hard water
Countries where tap water is safe to drink (blue)

According to the World Health Organization's 2017 report, safe drinking water is water that "does not represent any significant risk to health over a lifetime of consumption, including different sensitivities that may occur between life stages".[17]: 2 

According to a report by UNICEF and UNESCO, Finland has the best drinking water quality in the world.[18][19]

Parameters to monitor quality

Parameters for drinking water quality typically fall within three categories: microbiological, chemical, physical.

Microbiological parameters include coliform bacteria, E. coli, and specific pathogenic species of bacteria (such as cholera-causing Vibrio cholerae), viruses, and protozoan parasites. Originally, fecal contamination was determined with the presence of coliform bacteria, a convenient marker for a class of harmful fecal pathogens. The presence of fecal coliforms (like E. Coli) serves as an indication of contamination by sewage. Additional contaminants include protozoan oocysts such as Cryptosporidium sp., Giardia lamblia, Legionella, and viruses (enteric).[20] Microbial pathogenic parameters are typically of greatest concern because of their immediate health risk.

Example for physical and chemical parameters measured in drinking water samples in Kenya and Ethiopia as part of a systematic review of published literature.[21]

Physical and chemical parameters include heavy metals, trace organic compounds, total suspended solids, and turbidity. Chemical parameters tend to pose more of a chronic health risk through buildup of heavy metals although some components like nitrates/nitrites and arsenic can have a more immediate impact. Physical parameters affect the aesthetics and taste of the drinking water and may complicate the removal of microbial pathogens.

Pesticides are also potential drinking water contaminants of the category chemical contaminants. Pesticides may be present in drinking water in low concentrations, but the toxicity of the chemical and the extent of human exposure are factors that are used to determine the specific health risk.[22]

Perfluorinated alkylated substances (PFAS) are a group of synthetic compounds used in a large variety of consumer products, such as food packaging, waterproof fabrics, carpeting and cookware. PFAS are known to persist in the environment and are commonly described as persistent organic pollutants. PFAS chemicals have been detected in blood, both humans and animals, worldwide, as well as in food products, water, air and soil.[23] Animal testing studies with PFAS have shown effects on growth and development, and possibly effects on reproduction, thyroid, the immune system and liver.[24] As of 2022 the health impacts of many PFAS compounds are not understood. Scientists are conducting research to determine the extent and severity of impacts from PFAS on human health.[25] PFAS have been widely detected in drinking water worldwide and regulations have been developed, or are under development, in many countries.[26]

Drinking water quality standards
This section is an excerpt from Drinking water quality standards.[edit]

Drinking water quality standards describes the quality parameters set for drinking water. Water may contain many harmful constituents, yet there are no universally recognized and accepted international standards for drinking water. Even where standards do exist, the permitted concentration of individual constituents may vary by as much as ten times from one set of standards to another. Many countries specify standards to be applied in their own country. In Europe, this includes the European Drinking Water Directive[27] and in the United States, the United States Environmental Protection Agency (EPA) establishes standards as required by the Safe Drinking Water Act. China adopted its own drinking water standard GB3838-2002 (Type II) enacted by Ministry of Environmental Protection in 2002.[28] For countries without a legislative or administrative framework for such standards, the World Health Organization publishes guidelines on the standards that should be achieved.[29]

Where drinking water quality standards do exist, most are expressed as guidelines or targets rather than requirements, and very few water standards have any legal basis or, are subject to enforcement.[30] Two exceptions are the European Drinking Water Directive and the Safe Drinking Water Act in the United States,[31] which require legal compliance with specific standards. In Europe, this includes a requirement for member states to enact appropriate local legislation to mandate the directive in each country. Routine inspection and, where required, enforcement is enacted by means of penalties imposed by the European Commission on non-compliant nations.

Health issues due to low quality
Further information: WASH § Health aspects, and Waterborne diseases
Mortality rate attributable to unsafe water, sanitation, and hygiene (WASH).[32]
The "F-diagram" (feces, fingers, flies, fields, fluids, food), showing pathways of fecal–oral disease transmission. The vertical blue lines show barriers: toilets, safe water, hygiene and handwashing.

Contaminated water is estimated to result in more than half a million deaths per year.[1] Contaminated water together with the lack of sanitation was estimated to cause about one percent of disability adjusted life years worldwide in 2010.[33] According to the WHO, the most common diseases linked with poor water quality are cholera, diarrhea, dysentery, hepatitis A, typhoid, and polio.[34]

One of the main causes for contaminated drinking water in developing countries is lack of sanitation and poor hygiene. For this reason, the quantification of the burden of disease from consuming contaminated drinking water usually looks at water, sanitation and hygiene aspects together. The acronym for this is WASH - standing for water, sanitation and hygiene.

This section is an excerpt from WASH § WASH-attributable burden of diseases and injuries.[edit]

The WHO has investigated which proportion of death and disease worldwide can be attributed to insufficient WASH services. In their analysis they focus on the following four health outcomes: diarrhea, acute respiratory infections, undernutrition, and soil-transmitted helminthiases (STHs).[35]: vi  These health outcomes are also included as an indicator for achieving Sustainable Development Goal 3 ("Good Health and Wellbeing"): Indicator 3.9.2 reports on the "mortality rate attributed to unsafe water, sanitation, and lack of hygiene".

In 2023, WHO summarized the available data with the following key findings: "In 2019, use of safe WASH services could have prevented the loss of at least 1.4 million lives and 74 million disability-adjusted life years (DALYs) from four health outcomes. This represents 2.5% of all deaths and 2.9% of all DALYs globally."[35]: vi  Of the four health outcomes studied, it was diarrheal disease that had the most striking correlation, namely the highest number of "attributable burden of disease": over 1 million deaths and 55 million DALYs from diarrheal diseases was linked with lack of WASH. Of these deaths, 564,000 deaths were linked to unsafe sanitation in particular.

Diarrhea, malnutrition and stunting
Poverty often leads to unhygienic living conditions, as in this community in the Indian Himalayas. Such conditions promote contraction of diarrheal diseases, as a result of contaminated drinking water, poor sanitation and hygiene.
This section is an excerpt from WASH § Diarrhea, malnutrition and stunting.[edit]

Diarrhea is primarily transmitted through fecal–oral routes. In 2011, infectious diarrhea resulted in about 0.7 million deaths in children under five years old and 250 million lost school days.[36][37] This equates to about 2000 child deaths per day.[38] Children suffering from diarrhea are more vulnerable to become underweight (due to stunted growth).[39][40] This makes them more vulnerable to other diseases such as acute respiratory infections and malaria. Chronic diarrhea can have a negative effect on child development (both physical and cognitive).[41]

Numerous studies have shown that improvements in drinking water and sanitation (WASH) lead to decreased risks of diarrhea.[42] Such improvements might include for example use of water filters, provision of high-quality piped water and sewer connections.[42] Diarrhea can be prevented - and the lives of 525,000 children annually be saved (estimate for 2017) - by improved sanitation, clean drinking water, and hand washing with soap.[43] In 2008 the same figure was estimated as 1.5 million children.[44]

Consumption of contaminated groundwater
Main articles: Groundwater pollution and Arsenic contamination of groundwater

Sixty million people are estimated to have been poisoned by well water contaminated by excessive fluoride, which dissolved from granite rocks. The effects are particularly evident in the bone deformations of children. Similar or larger problems are anticipated in other countries including China, Uzbekistan, and Ethiopia. Although helpful for dental health in low dosage, fluoride in large amounts interferes with bone formation.[45]

Long-term consumption of water with high fluoride concentration (> 1.5 ppm F) can have serious undesirable consequences such as dental fluorosis, enamel mottle and skeletal fluorosis, bone deformities in children. Fluorosis severity depends on how much fluoride is present in the water, as well as people's diet and physical activity. Defluoridation methods include membrane-based methods, precipitation, absorption, and electrocoagulation.[46]

Natural arsenic contamination of groundwater is a global threat with 140 million people affected in 70 countries globally.[47]

Examples of poor drinking water quality incidents

Some well-known examples of water quality problems with drinking water supplies include:[48]

Water supply can get contaminated by pathogens which may originate from human excreta, for example due to a break-down or design fault in the sanitation system, or by chemical contaminants.

Further examples of contamination include:

  • In 1987, a cryptosporidiosis outbreak is caused by the public water supply of which the filtration was contaminated, in western Georgia[50]
  • In 1993, Milwaukee Cryptosporidium outbreak
  • In 1998, an outbreak of typhoid fever in northern Israel, which was associated with the contaminated municipal water supply[51]
  • In 1997, 369 cases of cryptosporidiosis occurred, caused by a contaminated fountain in the Minnesota zoo. Most of the sufferers were children[52]
  • In 1998, a non-chlorinated municipal water supply was blamed for a campylobacteriosis outbreak in northern Finland[53]
  • In 2000, a gastroenteritis outbreak that was brought by a non-chlorinated community water supply, in southern Finland[54]
  • In 2004, contamination of the community water supply, serving the Bergen city centre of Norway, was later reported after the outbreak of waterborne giardiasis[55]
  • In 2007, contaminated drinking water was pinpointed which had led to the outbreak of gastroenteritis with multiple aetiologies in Denmark[56]

Examples of chemical contamination include:

  • In 1988, many people were poisoned in Camelford, when a worker put 20 tonnes of aluminium sulphate in the wrong tank.
  • In 1993, a fluoride poisoning outbreak resulting from overfeeding of fluoride, in Mississippi[57]
  • In 2019 oil for an electric transformer oil entered the water supply for the city of Uummannaq in Greenland. A cargo ship in harbour was able to maintain a minimum supply the city for two days until the mains supply was restored and flushing of all the pipework was started.[58]

Treatment
Main articles: Water purification and Water treatment
Water treatment plant

Most water requires some treatment before use; even water from deep wells or springs. The extent of treatment depends on the source of the water. Appropriate technology options in water treatment include both community-scale and household-scale point-of-use (POU) designs.[59] Only a few large urban areas such as Christchurch, New Zealand have access to sufficiently pure water of sufficient volume that no treatment of the raw water is required.[60]

In emergency situations when conventional treatment systems have been compromised, waterborne pathogens may be killed or inactivated by boiling[61] but this requires abundant sources of fuel, and can be very onerous on consumers, especially where it is difficult to store boiled water in sterile conditions. Other techniques, such as filtration, chemical disinfection, and exposure to ultraviolet radiation (including solar UV) have been demonstrated in an array of randomized control trials to significantly reduce levels of water-borne disease among users in low-income countries,[62] but these suffer from the same problems as boiling methods.

Another type of water treatment is called desalination and is used mainly in dry areas with access to large bodies of saltwater.

Publicly available treated water has historically been associated with major increases in life expectancy and improved public health. Water disinfection can greatly reduce the risks of waterborne diseases such as typhoid and cholera. Chlorination is currently the most widely used water disinfection method, although chlorine compounds can react with substances in water and produce disinfection by-products (DBP) that pose problems to human health.[63] Local geological conditions affecting groundwater are determining factors for the presence of various metal ions, often rendering the water "soft" or "hard".

In the event of contamination of drinking water, government officials typically issue an advisory regarding water consumption. In the case of biological contamination, residents are usually advised to boil their water before consumption or to use bottled water as an alternative. In the case of chemical contamination, residents may be advised to refrain from consuming tap water entirely until the matter is resolved.

Point of use methods
Main articles: Portable water purification and Self-supply of water and sanitation

The ability of point of use (POU) options to reduce disease is a function of both their ability to remove microbial pathogens if properly applied and such social factors as ease of use and cultural appropriateness. Technologies may generate more (or less) health benefit than their lab-based microbial removal performance would suggest.

The current priority of the proponents of POU treatment is to reach large numbers of low-income households on a sustainable basis. Few POU measures have reached significant scale thus far, but efforts to promote and commercially distribute these products to the world's poor have only been under way for a few years.

Solar water disinfection is a low-cost method of purifying water that can often be implemented with locally available materials.[64][65][66][67] Unlike methods that rely on firewood, it has low impact on the environment.

Addition of fluoride

In many areas, low concentration of fluoride (< 1.0 ppm F) is intentionally added to tap water to improve dental health, although in some communities water fluoridation remains a controversial issue. (See water fluoridation controversy).

This section is an excerpt from Water fluoridation.[edit]
Water fluoridation is the controlled adjustment of fluoride to a public water supply solely to reduce tooth decay. Fluoridated water contains fluoride at a level that is effective for preventing cavities; this can occur naturally or by adding fluoride.[68] Fluoridated water operates on tooth surfaces: in the mouth, it creates low levels of fluoride in saliva, which reduces the rate at which tooth enamel demineralizes and increases the rate at which it remineralizes in the early stages of cavities.[69] Typically a fluoridated compound is added to drinking water, a process that in the U.S. costs an average of about $1.26 per person-year.[68][70] Defluoridation is needed when the naturally occurring fluoride level exceeds recommended limits.[71] In 2011, the World Health Organization suggested a level of fluoride from 0.5 to 1.5 mg/L (milligrams per litre), depending on climate, local environment, and other sources of fluoride.[72] Bottled water typically has unknown fluoride levels.[73]

Global access
Further information: WASH and List of countries by access to clean water
World map for SDG 6 Indicator 6.1.1 in 2015: "Proportion of population using safely managed drinking water services"
Population in survey regions living without safely managed drinking water as reported by the WHO/UNICEF JMP[7]

According to the World Health Organization (WHO), "access to safe drinking-water is essential to health, a basic human right and a component of effective policy for health protection."[17]: 2  In 1990, only 76 percent of the global population had access to drinking water. By 2015 that number had increased to 91 percent.[74] In 1990, most countries in Latin America, East and South Asia, and Sub-Saharan Africa were well below 90%. In Sub-Saharan Africa, where the rates are lowest, household access ranges from 40 to 80 percent.[74] Countries that experience violent conflict can have reductions in drinking water access: One study found that a conflict with about 2,500 battle deaths deprives 1.8% of the population of potable water.[75]

By 2015, 5.2 billion people representing 71% of the global population used safely managed drinking water services.[76] As of 2017, 90% of people having access to water from a source that is suitable for drinking – called improved water source – and 71% of the world could access safely managed drinking water that is clean and available on-demand.[1] Estimates suggest that at least 25% of improved sources contain fecal contamination.[77] 1.8 billion people still use an unsafe drinking water source which may be contaminated by feces.[1] This can result in infectious diseases, such as gastroenteritis, cholera, and typhoid, among others.[1] Reduction of waterborne diseases and development of safe water resources is a major public health goal in developing countries. In 2017, almost 22 million Americans drank from water systems that were in violation of public health standards, which could contribute to citizens developing water-borne illnesses.[78] Safe drinking water is an environmental health concern. Bottled water is sold for public consumption in most parts of the world.

Improved sources are also monitored based on whether water is available when needed (5.8 billion people), located on premises (5.4 billion), free from contamination (5.4 billion), and within a 30-minute round trip.[76]: 3  While improved water sources such as protected piped water are more likely to provide safe and adequate water as they may prevent contact with human excreta, for example, this is not always the case.[74] According to a 2014 study, approximately 25% of improved sources contained fecal contamination.[77]

The population in Australia, New Zealand, North America and Europe have achieved nearly universal basic drinking water services.[76]: 3 

Because of the high initial investments, many less wealthy nations cannot afford to develop or sustain appropriate infrastructure, and as a consequence people in these areas may spend a correspondingly higher fraction of their income on water.[79] 2003 statistics from El Salvador, for example, indicate that the poorest 20% of households spend more than 10% of their total income on water. In the United Kingdom, authorities define spending of more than 3% of one's income on water as a hardship.[80]

Global monitoring of access

The WHO/UNICEF Joint Monitoring Program (JMP) for Water Supply and Sanitation[81] is the official United Nations mechanism tasked with monitoring progress towards the Millennium Development Goal (MDG) relating to drinking-water and sanitation (MDG 7, Target 7c), which is to: "Halve, by 2015, the proportion of people without sustainable access to safe drinking-water and basic sanitation".[82]

Access to safe drinking water is indicated by safe water sources. These improved drinking water sources include household connection, public standpipe, borehole condition, protected dug well, protected spring, and rain water collection. Sources that do not encourage improved drinking water to the same extent as previously mentioned include: unprotected wells, unprotected springs, rivers or ponds, vender-provided water, bottled water (consequential of limitations in quantity, not quality of water), and tanker truck water. Access to sanitary water comes hand in hand with access to improved sanitation facilities for excreta, such as connection to public sewer, connection to septic system, or a pit latrine with a slab or water seal.[83]

According to this indicator on improved water sources, the MDG was met in 2010, five years ahead of schedule. Over 2 billion more people used improved drinking water sources in 2010 than did in 1990. However, the job is far from finished. 780 million people are still without improved sources of drinking water, and many more people still lack safe drinking water. Estimates suggest that at least 25% of improved sources contain fecal contamination[77] and an estimated 1.8 billion people globally use a source of drinking water that suffers from fecal contamination.[84] The quality of these sources varies over time and often gets worse during the wet season.[85] Continued efforts are needed to reduce urban-rural disparities and inequities associated with poverty; to dramatically increase safe drinking water coverage in countries in sub-Saharan Africa and Oceania; to promote global monitoring of drinking water quality; and to look beyond the MDG target towards universal coverage.[86]

Regulations
Main articles: Drinking water quality standards and List of water supply and sanitation by country

Guidelines for the assessment and improvement of service activities relating to drinking water have been published in the form of drinking water quality standards such as ISO 24510.[87]

European Union
See also: Water Framework Directive and Water supply and sanitation in the European Union

For example, the EU sets legislation on water quality. Directive 2000/60/EC of the European Parliament and of the Council of 23 October 2000 establishing a framework for Community action in the field of water policy, known as the water framework directive, is the primary piece of legislation governing water.[88] This drinking water directive relates specifically to water intended for human consumption. Each member state is responsible for establishing the required policing measures to ensure that the legislation is implemented. For example, in the UK the Water Quality Regulations prescribe maximum values for substances that affect wholesomeness and the Drinking Water Inspectorate polices the water companies.

Japan
See also: Water supply and sanitation in Japan

To improve water quality, Japan's Ministry of Health revised its water quality standards, which were implemented in April 2004.[89] Numerous professionals developed the drinking water standards.[89] They also determined ways to manage the high quality water system. In 2008, improved regulations were conducted to improve the water quality and reduce the risk of water contamination.[89]

New Zealand
See also: Water supply and sanitation in New Zealand

The Water Services Act 2021 brought Taumata Arowai' into existence as the new regulator of drinking water and waste water treatment in New Zealand. Initial activities including the establishment of a national register of water suppliers and establishing a network of accredited laboratories for drinking water and waste water analysis[90]

Singapore
See also: Water supply and sanitation in Singapore

Singapore is a significant importer of water from neighbouring Malaysia but also has made great efforts to reclaim as much used water as possible to ensure adequate provision for the very crowded city-state. Their reclaimed water is marketed as NEWater. Singapore updated its water quality regulation in 2019, setting standards consistent with the WHO recommended standards. Monitoring is undertaken by the Environmental Public Health Department of the Singaporean Government[91]

United Kingdom
See also: Water supply and sanitation in the United Kingdom

In the United Kingdom regulation of water supplies is a devolved matter to the Welsh and Scottish Parliaments and the Northern Ireland Assembly.

In England and Wales there are two water industry regulatory authorities.

  • Water Services Regulation Authority (Ofwat) is the economic regulator of the water sector; it protects the interests of consumers by promoting effective competition and ensuring that water companies carry out their statutory functions. Ofwat has a management board comprising a Chairman, Chief Executive and Executive and Non-Executive members. There is a staff of about 240.[92]
  • The Drinking Water Inspectorate (DWI) provides independent assurance that the privatised water industry delivers safe, clean drinking water to consumers. The DWI was established in 1990 and comprises a Chief Inspector of Drinking Water and a team of about 40 people.[93] The current standards of water quality are defined in Statutory Instrument 2016 No. 614 the Water Supply (Water Quality) Regulations 2016.[94]

The functions and duties of the bodies are formally defined in the Water Industry Act 1991 (1991 c. 56) as amended by the Water Act 2003 (2003 c. 37) and the Water Act 2014 (2014 c. 21).[95]

In Scotland water quality is the responsibility of independent Drinking Water Quality Regulator (DWQR).[96]

In Northern Ireland the Drinking Water Inspectorate (DWI) regulates drinking water quality of public and private supplies.[97] The current standards of water quality are defined in the Water Supply (Water Quality) Regulations (Northern Ireland) 2017.[98]

United States
Further information: Water supply and sanitation in the United States
This section is an excerpt from Drinking water quality in the United States.[edit]

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 (US EPA) standards.[99] 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.[100] The Safe Drinking Water Act requires the US EPA to set standards for drinking water quality in public water systems (entities that provide water for human consumption to at least 25 people for at least 60 days a year).[101] Enforcement of the standards is mostly carried out by state health agencies.[102] States may set standards that are more stringent than the federal standards.[103]

Drinking water 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.[104]

EPA has set standards for over 90 contaminants organized into six groups: microorganisms, disinfectants, disinfection byproducts, inorganic chemicals, organic chemicals and radionuclides.[105] EPA also identifies and lists unregulated contaminants which may require regulation. The Contaminant Candidate List is published every five years, and EPA is required to decide whether to regulate at least five or more listed contaminants.[106] There are also 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.[107]

History
Main article: History of water supply and sanitation

In drinking water access, quality and quantity are both important parameters but the quantity is often prioritized.[48] Throughout human history, water quality has been a constant and ongoing challenge. Certain crises have led to major changes in knowledge, policy, and regulatory structures. The drivers of change can vary: the cholera epidemic in the 1850s in London led John Snow to further our understanding of waterborne diseases. However, London’s sanitary revolution was driven by political motivations and social priorities before the science was accepted.[48]

See also

References
  1. "Water Fact sheet N°391". July 2014. Archived from the original on 5 June 2015. Retrieved 24 May 2015.
  2. Ann C. Grandjean (August 2004). "3" (PDF). Water Requirements, Impinging Factors, & Recommended Intakes. World Health Organization. pp. 25–34. Archived (PDF) from the original on 22 February 2016. This 2004 article focuses on the USA context and uses data collected from the US military.
  3. Exposure Factors Handbook: 2011 Edition (PDF). National Center for Environmental Assessment. September 2011. Archived from the original (PDF) on 24 September 2015. Retrieved 24 May 2015.
  4. "Drinking-water". World Health Organization. March 2018. Retrieved 23 March 2018.
  5. "Unsafe water kills more people than war, Ban says on World Day". UN News. 22 March 2010. Retrieved 10 May 2018.
  6. Hall, Ellen L.; Dietrich, Andrea M. (2000). "A Brief History of Drinking Water." Archived 8 February 2015 at the Wayback Machine Washington: American Water Works Association. Product No. OPF-0051634, Accessed 13 June 2012.
  7. Lord, Jackson; Thomas, Ashley; Treat, Neil; Forkin, Matthew; Bain, Robert; Dulac, Pierre; Behroozi, Cyrus H.; Mamutov, Tilek; Fongheiser, Jillia; Kobilansky, Nicole; Washburn, Shane; Truesdell, Claudia; Lee, Clare; Schmaelzle, Philipp H. (October 2021). "Global potential for harvesting drinking water from air using solar energy". Nature. 598 (7882): 611–617. Bibcode:2021Natur.598..611L. doi:10.1038/s41586-021-03900-w. ISSN 1476-4687. PMC 8550973. PMID 34707305.
  8. Schardt, David (2000). "Water, Water Everywhere". Washington, D.C.: Center for Science in the Public Interest. Archived from the original on 16 May 2009.
  9. United Nations. World Water Assessment Programme (2009). "Water in a Changing World: Facts and Figures." Archived 24 June 2012 at the Wayback Machine World Water Development Report 3. p. 58 Accessed 13 June 2012.
  10. Mayer, P.W.; DeOreo, W.B.; Opitz, E.M.; Kiefer, J.C.; Davis, W.Y.; Dziegielewski, B.; & Nelson, J.O., 1999. Residential End Uses of Water. AWWARF and AWWA, Denver.
  11. William B. DeOreo, Peter Mayer, Benedykt Dziegielewski, Jack Kiefer. 2016. Residential End Uses of Water, Version 2. Water Research Foundation. Denver, Colorado.
  12. Joseph Cotruvo, Victor Kimm, Arden Calvert. "Drinking Water: A Half Century of Progress." EPA Alumni Association. 1 March 2016.
  13. "Drinking Water Regulations". www.epa.gov. 21 September 2015. Retrieved 4 October 2021.
  14. Ann C. Grandjean (August 2004). "3" (PDF). Water Requirements, Impinging Factors, & Recommended Intakes. World Health Organization. pp. 25–34. Archived (PDF) from the original on 22 February 2016. This 2004 article focuses on the USA context and uses data collected from the US military.
  15. "US daily reference intake values". Iom.edu. Archived from the original on 6 October 2011. Retrieved 5 December 2011.
  16. EFSA Panel on Dietetic Products, Nutrition, and Allergies (2010). "Scientific Opinion on Dietary Reference Values for water". EFSA Journal. 8 (3): 1459. doi:10.2903/j.efsa.2010.1459.{{cite journal}}: CS1 maint: multiple names: authors list (link)
  17. Guidelines for Drinking‑water Quality (PDF) (Report) (4 ed.). World Health Organization. 2017. p. 631. ISBN 978-92-4-154995-0.
  18. "WWDR1: Water for People – water for life" (PDF). UNESCO and Berghahn Books. 2003. Retrieved 21 September 2022.
  19. "The quality of water produced by Turku Region Water is rated the best in the world by Unesco". City of Turku. 1 December 2021. Retrieved 21 September 2022.
  20. "Drinking Water Contaminants: Microorganisms". EPA. 21 September 2010. Archived from the original on 2 February 2015.
  21. Nowicki, Saskia; Birhanu, Behailu; Tanui, Florence; Sule, May N.; Charles, Katrina; Olago, Daniel; Kebede, Seifu (2023). "Water chemistry poses health risks as reliance on groundwater increases: A systematic review of hydrogeochemistry research from Ethiopia and Kenya". Science of the Total Environment. 904: 166929. Bibcode:2023ScTEn.904p6929N. doi:10.1016/j.scitotenv.2023.166929. PMID 37689199. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License
  22. "Drinking Water and Pesticides". National Pesticide Information Center. Corvallis, OR: Oregon State University. 16 September 2021.
  23. "PFAS Explained". EPA. 18 October 2021.
  24. "Per- and Polyfluorinated Substances Factsheet". CDC. 16 August 2021.
  25. "Increasing Our Understanding of the Health Risks from PFAS and How to Address Them". EPA. 3 November 2021.
  26. Kurwadkar, Sudarshan; Danea, Jason; Kanel, Sushil R.; et al. (22 October 2021). "Per- and polyfluoroalkyl substances in water and wastewater: A critical review of their global occurrence and distribution". Science of the Total Environment. Elsevier. 809: 151003. doi:10.1016/j.scitotenv.2021.151003. PMC 10184764. PMID 34695467. S2CID 239494337.
  27. "European Drinking Water Directive". Directorate-General for Environment. Brussels: European Commission.
  28. "Environmental quality standards for surface water".
  29. Guidelines for Drinking-water Quality, Fourth Edition; World Health Organization; 2022
  30. What is the purpose of drinking water quality guidelines/regulations?. Canada: Safe Drinking Water Foundation. Pdf. Archived 2011-10-06 at the Wayback Machine
  31. "Summary of the Safe Drinking Water Act". Washington, D.C.: U.S. Environmental Protection Agency (EPA). 2022-09-12.
  32. "Mortality rate attributable to unsafe water, sanitation, and hygiene (WASH)". Our World in Data. Retrieved 5 March 2020.
  33. Engell, Rebecca E; Lim, Stephen S (2013). "Does clean water matter? An updated meta-analysis of water supply and sanitation interventions and diarrhoeal diseases". The Lancet. 381: S44. doi:10.1016/S0140-6736(13)61298-2.
  34. "Drinking-water". www.who.int.
  35. WHO (2023) Burden of disease attributable to unsafe drinking-water, sanitation and hygiene, 2019 update. Geneva: World Health Organization; 2023. Licence: CC BY-NC-SA 3.0 IGO.
  36. "Call to action on sanitation" (PDF). United Nations. Retrieved 15 August 2014.
  37. Walker CL, Rudan I, Liu L, Nair H, Theodoratou E, Bhutta ZA, et al. (April 2013). "Global burden of childhood pneumonia and diarrhoea". Lancet. 381 (9875): 1405–1416. doi:10.1016/S0140-6736(13)60222-6. PMC 7159282. PMID 23582727.
  38. "WHO | Diarrhoeal disease". Who.int. Retrieved 2014-03-10.
  39. Spears D, Ghosh A, Cumming O (2013-09-16). "Open defecation and childhood stunting in India: an ecological analysis of new data from 112 districts". PLOS ONE. 8 (9): e73784. Bibcode:2013PLoSO...873784S. doi:10.1371/journal.pone.0073784. PMC 3774764. PMID 24066070.
  40. Mara D (2017). "The elimination of open defecation and its adverse health effects: a moral imperative for governments and development professionals". Journal of Water Sanitation and Hygiene for Development. 7 (1): 1–12. doi:10.2166/washdev.2017.027. ISSN 2043-9083.
  41. "Water, Sanitation & Hygiene: Strategy Overview". Bill & Melinda Gates Foundation. Retrieved 27 April 2015.
  42. Wolf J, Prüss-Ustün A, Cumming O, Bartram J, Bonjour S, Cairncross S, et al. (August 2014). "Assessing the impact of drinking water and sanitation on diarrhoeal disease in low- and middle-income settings: systematic review and meta-regression". Tropical Medicine & International Health. 19 (8): 928–942. doi:10.1111/tmi.12331. PMID 24811732. S2CID 22903164.
  43. "Diarrhoeal disease Fact sheet". World Health Organization. 2 May 2017. Retrieved 29 October 2020.
  44. Progress on Drinking Water and Sanitation: Special Focus on Sanitation, Joint Monitoring Programme for Water Supply and Sanitation (PDF). World Health Organization and UNICEF. 2008. ISBN 978-92-806-4313-8. Archived from the original (PDF) on 12 February 2009.
  45. Pearce, Fred (2006). When the Rivers Run Dry: Journeys Into the Heart of the World's Water Crisis. Toronto: Key Porter. ISBN 978-1-55263-741-8.
  46. Ahuja, Satinder (2018). Advances in Water Purification Techniques: Meeting the Needs of Developed and Developing Countries. San Diego: Elsevier. ISBN 978-0-12-814791-7. OCLC 1078565849.
  47. Bagchi, Sanjit (20 November 2007). "Arsenic threat reaching global dimensions" (PDF). Canadian Medical Association Journal. 177 (11): 1344–45. doi:10.1503/cmaj.071456. ISSN 1488-2329. PMC 2072985. PMID 18025421.
  48. Khan, Nameerah; Charles, Katrina J. (2023). "When Water Quality Crises Drive Change: A Comparative Analysis of the Policy Processes Behind Major Water Contamination Events". Exposure and Health. 15 (3): 519–537. doi:10.1007/s12403-022-00505-0. ISSN 2451-9766. PMC 9522453. PMID 36196073. Text was copied from this source, which is available under a Creative Commons Attribution 4.0 International License
  49. "Canada's worst-ever E. coli contamination". CBC. Retrieved 18 September 2009.
  50. Hayes EB, Matte TD, O'Brien TR, et al. (May 1989). "Large community outbreak of cryptosporidiosis due to contamination of a filtered public water supply". N. Engl. J. Med. 320 (21): 1372–76. doi:10.1056/NEJM198905253202103. PMID 2716783.
  51. Egoz N, Shihab S, Leitner L, Lucian M (November 1988). "An outbreak of typhoid fever due to contamination of the municipal water supply in northern Israel". Isr. J. Med. Sci. 24 (11): 640–43. PMID 3215755.
  52. Centers for Disease Control and Prevention (CDC) (October 1998). "Outbreak of cryptosporidiosis associated with a water sprinkler fountain – Minnesota, 1997". MMWR Morb. Mortal. Wkly. Rep. 47 (40): 856–60. PMID 9790661.
  53. Kuusi M, Nuorti JP, Hänninen ML, et al. (August 2005). "A large outbreak of campylobacteriosis associated with a municipal water supply in Finland". Epidemiol. Infect. 133 (4): 593–601. doi:10.1017/S0950268805003808. PMC 2870285. PMID 16050503.
  54. Kuusi M, Klemets P, Miettinen I, et al. (April 2004). "An outbreak of gastroenteritis from a non-chlorinated community water supply". J Epidemiol Community Health. 58 (4): 273–77. doi:10.1136/jech.2003.009928. PMC 1732716. PMID 15026434.
  55. Nygård K, Schimmer B, Søbstad Ø, et al. (2006). "A large community outbreak of waterborne giardiasis-delayed detection in a non-endemic urban area". BMC Public Health. 6: 141. doi:10.1186/1471-2458-6-141. PMC 1524744. PMID 16725025.
  56. Vestergaard LS, Olsen KE, Stensvold R, et al. (March 2007). "Outbreak of severe gastroenteritis with multiple aetiologies caused by contaminated drinking water in Denmark, January 2007". Euro Surveill. 12 (3): E070329.1. doi:10.2807/esw.12.13.03164-en. PMID 17439795.
  57. Penman AD, Brackin BT, Embrey R (1997). "Outbreak of acute fluoride poisoning caused by a fluoride overfeed, Mississippi, 1993". Public Health Rep. 112 (5): 403–09. PMC 1381948. PMID 9323392.
  58. "Uummannaq: Vand fra vandværket kan drikkes igen". Sermitsiaq.AG (in Danish). Retrieved 2020-09-23.
  59. Centre for Affordable Water and Sanitation Technology. Calgary, Alberta. "Household Water Treatment Guide," March 2008. Archived 20 September 2008 at the Wayback Machine.
  60. "Our water – Water supply". Christchurch City Council. Christchurch, NZ. Archived from the original on 12 May 2015.
  61. World Health Organization, Geneva (2004). "Guidelines for Drinking-water Quality. Volume 1: Recommendations." Archived 4 March 2016 at the Wayback Machine 3rd ed.
  62. Clasen, T.; Schmidt, W.; Rabie, T.; Roberts, I.; Cairncross, S. (12 March 2007). "Interventions to improve water quality for preventing diarrhoea: systematic review and meta-analysis". British Medical Journal. 334 (7597): 782. doi:10.1136/bmj.39118.489931.BE. PMC 1851994. PMID 17353208.
  63. Water disinfection. Kelly M. Buchanan. Hauppauge, N.Y.: Nova Science Publishers. 2010. ISBN 978-1-61122-401-6. OCLC 730450380.{{cite book}}: CS1 maint: others (link)
  64. Conroy, RM.; Meegan, ME.; Joyce, T.; McGuigan, K.; Barnes, J. (October 1999). "Solar disinfection of water reduces diarrhoeal disease: an update". Arch Dis Child. 81 (4): 337–38. doi:10.1136/adc.81.4.337. PMC 1718112. PMID 10490440.
  65. Conroy, R.M.; Meegan, M.E.; Joyce, T.M.; McGuigan, K.G.; Barnes, J. (2001). "Solar disinfection of drinking water protects against cholera in children under 6 years of age". Arch Dis Child. 85 (4): 293–95. doi:10.1136/adc.85.4.293. PMC 1718943. PMID 11567937.
  66. Rose, A; Roy, S; Abraham, V; Holmgren, G; George, K; Balraj, V; Abraham, S; Muliyil, J; et al. (2006). "Solar disinfection of water for diarrhoeal prevention in southern India". Arch Dis Child. 91 (2): 139–41. doi:10.1136/adc.2005.077867. PMC 2082686. PMID 16403847.
  67. Hobbins M. (2003). The SODIS Health Impact Study, Ph.D. Thesis, Swiss Tropical Institute Basel
  68. "Recommendations for using fluoride to prevent and control dental caries in the United States. Centers for Disease Control and Prevention". MMWR. Recommendations and Reports. 50 (RR-14): 1–42. August 2001. PMID 11521913. See also lay summary from CDC, 2007-08-09.
  69. Pizzo G, Piscopo MR, Pizzo I, Giuliana G (September 2007). "Community water fluoridation and caries prevention: a critical review". Clinical Oral Investigations. 11 (3): 189–193. doi:10.1007/s00784-007-0111-6. PMID 17333303. S2CID 13189520.
  70. 1634–1699: McCusker, J. J. (1997). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States: Addenda et Corrigenda (PDF). American Antiquarian Society. 1700–1799: McCusker, J. J. (1992). How Much Is That in Real Money? A Historical Price Index for Use as a Deflator of Money Values in the Economy of the United States (PDF). American Antiquarian Society. 1800–present: Federal Reserve Bank of Minneapolis. "Consumer Price Index (estimate) 1800–". Retrieved May 28, 2023.
  71. Taricska JR, Wang LK, Hung YT, Li KH (2006). "Fluoridation and defluoridation". In Wang LK, Hung YT, Shammas NK (eds.). Advanced Physicochemical Treatment Processes. Handbook of Environmental Engineering 4. Humana Press. pp. 293–315. doi:10.1007/978-1-59745-029-4_9. ISBN 978-1597450294.
  72. Guidelines for Drinking-water Quality, 4th Edition WHO, 2011. ISBN 978-9241548151. p. 168, 175, 372 and see also pp 370–373. See also J. Fawell, et al Fluoride in Drinking-water. WHO, 2006. p. 32. Quote: "Concentrations in drinking-water of about 1 mg l–1 are associated with a lower incidence of dental caries, particularly in children, whereas excess intake of fluoride can result in dental fluorosis. In severe cases this can result in erosion of enamel. The margin between the beneficial effects of fluoride and the occurrence of dental fluorosis is small and public health programmes seek to retain a suitable balance between the two"
  73. Hobson WL, Knochel ML, Byington CL, Young PC, Hoff CJ, Buchi KF (May 2007). "Bottled, filtered, and tap water use in Latino and non-Latino children". Archives of Pediatrics & Adolescent Medicine. 161 (5): 457–461. doi:10.1001/archpedi.161.5.457. PMID 17485621.
  74. Ritchie, Hannah; Roser, Max (2018), "Water Access, Resources & Sanitation", OurWorldInData.org, retrieved 22 March 2018
  75. Davenport, Christian; Mokleiv Nygård, Håvard; Fjelde, Hanne; Armstrong, David (2019). "The Consequences of Contention: Understanding the Aftereffects of Political Conflict and Violence". Annual Review of Political Science. 22: 361–377. doi:10.1146/annurev-polisci-050317-064057.
  76. Progress on Drinking Water, Sanitation and Hygiene (PDF) (Report). JMP, WHO and UNICEF. 2014. ISBN 978-92-4-151289-3. Retrieved 22 March 2018.
  77. Bain, R.; Cronk, R.; Wright, J.; Yang, H.; Slaymaker, T.; Bartram, J. (2014). "Fecal Contamination of Drinking-Water in Low- and Middle-Income Countries: A Systematic Review and Meta-Analysis". PLOS Medicine. 11 (5): e1001644. doi:10.1371/journal.pmed.1001644. PMC 4011876. PMID 24800926.
  78. U.S. Environmental Protection Agency. Report on the environment: drinking water. Available at: https://cfpub.epa.gov . Accessed March 3, 2023.
  79. "The water vendors of Nigeria". 5 February 2009. Archived from the original on 22 October 2009. Retrieved 23 October 2009. BBC News The water vendors of Nigeria Referenced 20 October 2008
  80. "| Human Development Reports" (PDF). Retrieved 23 October 2009. page 51 Referenced 20 October 2008
  81. "About the JMP". JMP. WHO and UNICEF. Retrieved 16 October 2019.
  82. United Nations:World Water Assessment Program Archived 21 January 2008 at the Wayback Machine, accessed on 27 February 2010
  83. "Meeting the MDG Drinking Water and Sanitation Target: A Mid-Term Assessment of Progress" (PDF). Archived from the original (PDF) on March 4, 2016.
  84. Bain, R.; Cronk, R.; Hossain, R.; Bonjour, S.; Onda, K.; Wright, J.; Yang, H.; Slaymaker, T.; Hunter, P.; Prüss-Ustün, A.; Bartram, J. (2014). "Global assessment of exposure to faecal contamination through drinking water based on a systematic review". Tropical Medicine & International Health. 19 (8): 917–27. doi:10.1111/tmi.12334. PMC 4255778. PMID 24811893.
  85. Kostyla, C.; Bain, R.; Cronk, R.; Bartram, J. (2015). "Seasonal variation of fecal contamination in drinking water sources in developing countries: A systematic review". Science of the Total Environment. 514: 333–43. Bibcode:2015ScTEn.514..333K. doi:10.1016/j.scitotenv.2015.01.018. PMID 25676921.
  86. "Progress on Drinking-water and Sanitation: 2012 Update" (PDF). Archived from the original (PDF) on 28 March 2012.
  87. ISO 24510 Activities relating to drinking water and wastewater services. Guidelines for the assessment and for the improvement of the service to users
  88. Maria, Kaika (April 2003). "The Water Framework Directive: A New Directive for a Changing Social, Political and Economic European Framework". European Planning Studies. 11 (3): 299–316. doi:10.1080/09654310303640. S2CID 153351550.
  89. "Ministry of Health, Labour and Welfare: Water Supply in Japan". www.mhlw.go.jp. Retrieved 2021-11-18.
  90. "Taumata Arowai: a new water regulator". NZ Ministry of Health. 9 June 2022. Retrieved 28 June 2022.
  91. "Our Drinking Water Quality" (PDF). Singapore National Water Agency. Retrieved 28 June 2022.
  92. "Our duties". About us. London: Ofwat (Water Services Regulation Authority). Retrieved 2020-10-23.
  93. "What We Do". About Us. London: Drinking Water Inspectorate. 2020-06-15.
  94. "The Water Supply (Water Quality) Regulations 2016". UK Statutory Instruments. London: National Archives, UK. Retrieved 2020-10-23.
  95. "Water Industry Act 1991". UK Public General Acts. London: National Archives, UK. Retrieved 2020-10-23.
  96. "Water Quality Regulator says Scotland's tap water quality remains high". News. Edinburgh: Scottish Government. 2019-08-05.
  97. "Duties of the Drinking Water Inspectorate". Belfast: Northern Ireland Environment Agency. 26 May 2016. Retrieved 2020-10-23.
  98. "The Water Supply (Water Quality) Regulations (Northern Ireland) 2017". Northern Ireland Statutory Rules. London: National Archives, UK. Retrieved 2020-10-23.
  99. Beauvais, Joel (April 26, 2016). "Moving Forward for America's Drinking Water". EPA Blog. Washington, D.C.: U.S. Environmental Protection Agency (EPA).
  100. "Public Water Systems". Atlanta, GA: U.S. Centers for Disease Control and Prevention (CDC). April 7, 2014.
  101. United States. Safe Drinking Water Act. Pub. L.Tooltip Public Law (United States) 93–523; 88 Stat. 1660; 42 U.S.C. § 300f et seq. 1974-12-16.
  102. "Primacy Enforcement Responsibility for Public Water Systems". Drinking Water Requirements for States and Public Water Systems. Washington, D.C.: United States Environmental Protection Agency (EPA). 2016-11-02.
  103. Understanding the Safe Drinking Water Act (Report). EPA. June 2004. EPA 816-F-04-030.
  104. Joseph Cotruvo, Victor Kimm, Arden Calvert. "Drinking Water: A Half Century of Progress." EPA Alumni Association. March 1, 2016.
  105. "National Primary Drinking Water Regulations". Ground Water and Drinking Water. EPA. 2019-09-17.
  106. "Basic Information on the CCL and Regulatory Determination". Contaminant Candidate List. EPA. 2019-07-19.
  107. "Basic Information on the CCL and Regulatory Determination". Contaminant Candidate List (CCL). EPA. 2022-03-21.
Look up drinking water in Wiktionary, the free dictionary.
Wikibooks has a book on the topic of: Drinking water
Wikimedia Commons has media related to Drinking water.
Wikivoyage has a travel guide for Water.
Look up drinking water or potable in Wiktionary, the free dictionary.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.