Drinking water

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Drinking water that is supplied through a tap (tap water) Clean water for a village in West Lombok (10686572086).jpg
Drinking water that is supplied through a tap (tap 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.

Contents

The amount of drinking water required to maintain good health varies, and depends on physical activity level, age, health-related issues, and environmental conditions. [1] [2] For those who work in a hot climate, up to 16 litres (4.2 US gal) a day may be required. [1]

About 1 to 2 billion people lack safe drinking water. [3] 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. [4] Developing countries are most affected by unsafe drinking water.

Sources

Drinking water vending machines in Thailand. One litre of potable water is sold (into the customer's own bottle) for 1 baht. E8661-Pattaya-water-vending-machines.jpg
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 Water well types wiki.svg
Diagram of water well types
Simplified diagram of a water supply network Water system.pdf
Simplified diagram of a water supply network

Potable water is available in almost all populated areas of the world, 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. [5]

An experimental source is atmospheric water generators. [6]

Springs are often used as sources for bottled waters. [7]

Supply

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. [8]

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

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. [9] [10] Of this, only 1% of the water provided by public water suppliers is for drinking and cooking. [11] Uses include (in decreasing order) toilets, washing machines, showers, baths, faucets, and leaks.

Total renewable water resources per capita in 2020 Total Renewable Water Resources Per Capita (2020).svg
Total renewable water resources per capita in 2020

As of 2015, American households use an average of 300 gallons of water a day. [12]

Usage for drinking

This section is an excerpt from Daily consumption of drinking water.[ edit ]
The recommended daily amount of drinking water for humans varies. [13] It depends on activity, age, health, and environment. In the United States, the Adequate Intake for total water, based on median intakes, is 4.0 litres (141 imp fl oz; 135 US fl oz) per day for males older than 18, and 3.0 litres (106 imp fl oz; 101 US fl oz) per day for females over 18; it assumes about 80% from drink and 20% from food. [14] The European Food Safety Authority recommends 2.0 litres (70 imp fl oz; 68 US fl oz) of total water per day for women and 2.5 litres (88 imp fl oz; 85 US fl oz) per day for men. [15]

Animals

The qualitative and quantitative aspects of drinking water requirements on domesticated animals are studied and described within the context of animal husbandry. For example, a farmer might plan for 35 U.S. gallons (130 L) per day for a dairy cow, a third of that for a horse, and a tenth of that for a hog. [16]

However, relatively few studies have been focused on the drinking behavior of wild animals.

Quality

Countries where tap water is safe to drink (blue) Safe drink tap water map.png
Countries where tap water is safe to drink (blue)

According to the World Health Organization's 2017 report, safedrinking 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 1-s2.0-S0048969723055547-gr5 lrg.jpg
Example for physical and chemical parameters measured in drinking water samples in Kenya and Ethiopia as part of a systematic review of published literature

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

Mortality rate attributable to unsafe water, sanitation, and hygiene (WASH) Mortality rate attributable to unsafe water, sanitation, and hygiene (WASH), OWID.svg
Mortality rate attributable to unsafe water, sanitation, and hygiene (WASH)
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. F-diagram-01.jpg
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.

The World Health Organization considers access to safe drinking-water a basic human right. Contaminated water is estimated to result in more than half a million deaths per year. [33] Contaminated water together with the lack of sanitation was estimated to cause about one percent of disability adjusted life years worldwide in 2010. [34] According to the WHO, the most common diseases linked with poor water quality are cholera, diarrhea, dysentery, hepatitis A, typhoid, and polio. [35]

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, malnutrition, and soil-transmitted Helminthiasis (STHs). [36] : vi  These health outcomes are also included as an indicator for achieving Sustainable Development Goal 3 ("Good Health and Well-being"): 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." [36] : 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. Slum and dirty river.jpg
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. [37] [38] This equates to about 2000 child deaths per day. [39] Children suffering from diarrhea are more vulnerable to become underweight (due to stunted growth). [40] [41] 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). [42]

Numerous studies have shown that improvements in drinking water and sanitation (WASH) lead to decreased risks of diarrhea. [43] Such improvements might include for example use of water filters, provision of high-quality piped water and sewer connections. [43] 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. [44] In 2008 the same figure was estimated as 1.5 million children. [45]

Consumption of contaminated 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. [46]

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. [47]

Natural arsenic contamination of groundwater is a global threat with 140 million people affected in 70 countries globally. [48]

Examples of poor drinking water quality incidents

Some well-known examples of water quality problems with drinking water supplies include: [49]

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

Further examples of contamination include:

Examples of chemical contamination include:

Treatment

Water treatment plant Water Treatment Plant.jpg
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. [60] 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. [61]

In emergency situations when conventional treatment systems have been compromised, waterborne pathogens may be killed or inactivated by boiling [62] 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, [63] 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. [64] Local geological conditions affecting groundwater are determining factors for the presence of various metal ions, often rendering the water "soft" or "hard".[ citation needed ]

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

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. [65] [66] [67] [68] 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 addition of fluoride to a public water supply 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. [69] 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. [70] Typically a fluoridated compound is added to drinking water, a process that in the U.S. costs an average of about $1.32 per person-year. [69] [71] Defluoridation is needed when the naturally occurring fluoride level exceeds recommended limits. [72] 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. [73] In 2024, the Department of Health and Human Services' National Toxicology Program found that higher cumulative fluoride exposure is consistently linked to lower IQ in children, even within the range of ordinary water fluoridation levels. These findings emphasize that as fluoride exposure increases, IQ consistently decreases, regardless of whether the exposure is considered normal or within regulatory limits. [74] Recent U.S. court rulings have raised concerns about the potential health risks of water fluoridation, including findings by the EPA and new risk assessments that suggest the benefits may be waning. [75] [76] [77] Bottled water typically has unknown fluoride levels. [78]

Global access

World map for SDG 6 Indicator 6.1.1 in 2015: "Proportion of population using safely managed drinking water services" Share of the population using safely managed drinking water, OWID.svg
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 Population in survey regions living without safely managed drinking water.webp
Population in survey regions living without safely managed drinking water as reported by the WHO/UNICEF JMP

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. [79] 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. [79] 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. [80]

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. [33]

Globally, by 2015, 89% of people had access to water from a source that is suitable for drinking –called improved water sources. [33] 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. [33]

By 2015, 5.2 billion people representing 71% of the global population used safely managed drinking water services. [81] 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. [33] Estimates suggest that at least 25% of improved sources contain fecal contamination. [82] 1.8 billion people still use an unsafe drinking water source which may be contaminated by feces. [33] This can result in infectious diseases, such as gastroenteritis, cholera, and typhoid, among others. [33] 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. [83] [ full citation needed ] 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. [81] : 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. [79] According to a 2014 study, approximately 25% of improved sources contained fecal contamination. [82]

The population in Australia, New Zealand, North America and Europe have achieved nearly universal basic drinking water services. [81] : 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. [84] 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. [85]

Global monitoring of access

The WHO/UNICEF Joint Monitoring Program (JMP) for Water Supply and Sanitation [86] 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". [87]

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. [88]

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 [82] and an estimated 1.8 billion people globally use a source of drinking water that suffers from fecal contamination. [89] The quality of these sources varies over time and often gets worse during the wet season. [90] 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. [91]

Regulations

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. [92]

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. [93] 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

To improve water quality, Japan's Ministry of Health revised its water quality standards, which were implemented in April 2004. [94] Numerous professionals developed the drinking water standards. [94] 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. [94]

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 [95]

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 [96]

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.

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). [100]

In Scotland water quality is the responsibility of independent Drinking Water Quality Regulator (DWQR). [101]

In Northern Ireland the Drinking Water Inspectorate (DWI) regulates drinking water quality of public and private supplies. [102] The current standards of water quality are defined in the Water Supply (Water Quality) Regulations (Northern Ireland) 2017. [103]

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. [104] 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. [105] 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). [106] Enforcement of the standards is mostly carried out by state health agencies. [107] States may set standards that are more stringent than the federal standards. [108]

Despite improvements in water quality regulations, disparities in access to clean drinking water persist in marginalized communities. A 2017 study by the Natural Resources Defense Council (NRDC) highlighted that rural areas and low-income neighborhoods are disproportionately affected by water contamination, often due to aging infrastructure and inadequate funding for water systems. [109] These inequities underscore the need for more targeted investment and stronger enforcement of the Safe Drinking Water Act in vulnerable regions.

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. [110]

History

In drinking water access, quality and quantity are both important parameters but the quantity is often prioritized. [49] 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. [49]

See also

Related Research Articles

Fluoride is an inorganic, monatomic anion of fluorine, with the chemical formula F−
, whose salts are typically white or colorless. Fluoride salts typically have distinctive bitter tastes, and are odorless. Its salts and minerals are important chemical reagents and industrial chemicals, mainly used in the production of hydrogen fluoride for fluorocarbons. Fluoride is classified as a weak base since it only partially associates in solution, but concentrated fluoride is corrosive and can attack the skin.

<span class="mw-page-title-main">Sanitation</span> Public health conditions related to clean water and proper excreta and sewage disposal

Sanitation refers to public health conditions related to clean drinking water and treatment and disposal of human excreta and sewage. Preventing human contact with feces is part of sanitation, as is hand washing with soap. Sanitation systems aim to protect human health by providing a clean environment that will stop the transmission of disease, especially through the fecal–oral route. For example, diarrhea, a main cause of malnutrition and stunted growth in children, can be reduced through adequate sanitation. There are many other diseases which are easily transmitted in communities that have low levels of sanitation, such as ascariasis, cholera, hepatitis, polio, schistosomiasis, and trachoma, to name just a few.

Water purification is the process of removing undesirable chemicals, biological contaminants, suspended solids, and gases from water. The goal is to produce water that is fit for specific purposes. Most water is purified and disinfected for human consumption, but water purification may also be carried out for a variety of other purposes, including medical, pharmacological, chemical, and industrial applications. The history of water purification includes a wide variety of methods. The methods used include physical processes such as filtration, sedimentation, and distillation; biological processes such as slow sand filters or biologically active carbon; chemical processes such as flocculation and chlorination; and the use of electromagnetic radiation such as ultraviolet light.

<span class="mw-page-title-main">Tap water</span> Water supplied through a pipe and tap combination

Tap water is water supplied through a tap, a water dispenser valve. In many countries, tap water usually has the quality of drinking water. Tap water is commonly used for drinking, cooking, washing, and toilet flushing. Indoor tap water is distributed through indoor plumbing, which has been around since antiquity but was available to very few people until the second half of the 19th century when it began to spread in popularity in what are now developed countries. Tap water became common in many regions during the 20th century, and is now lacking mainly among people in poverty, especially in developing countries.

<span class="mw-page-title-main">Water fluoridation</span> Addition of fluoride to a water supply to reduce tooth decay

Water fluoridation is the addition of fluoride to a public water supply 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. 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. Typically a fluoridated compound is added to drinking water, a process that in the U.S. costs an average of about $1.32 per person-year. Defluoridation is needed when the naturally occurring fluoride level exceeds recommended limits. In 2011, the World Health Organization suggested a level of fluoride from 0.5 to 1.5 mg/L, depending on climate, local environment, and other sources of fluoride. In 2024, the Department of Health and Human Services' National Toxicology Program found that higher cumulative fluoride exposure is consistently linked to lower IQ in children, even within the range of ordinary water fluoridation levels. These findings emphasize that as fluoride exposure increases, IQ consistently decreases, regardless of whether the exposure is considered normal or within regulatory limits. Recent U.S. court rulings have raised concerns about the potential health risks of water fluoridation, including findings by the EPA and new risk assessments that suggest the benefits may be waning. Bottled water typically has unknown fluoride levels.

Fluoride toxicity is a condition in which there are elevated levels of the fluoride ion in the body. Although fluoride is safe for dental health at low concentrations, sustained consumption of large amounts of soluble fluoride salts is dangerous. Referring to a common salt of fluoride, sodium fluoride (NaF), the lethal dose for most adult humans is estimated at 5 to 10 g. Ingestion of fluoride can produce gastrointestinal discomfort at doses at least 15 to 20 times lower than lethal doses. Although it is helpful topically for dental health in low dosage, chronic ingestion of fluoride in large amounts interferes with bone formation. In this way, the most widespread examples of fluoride poisoning arise from consumption of ground water that is abnormally fluoride-rich.

The water fluoridation controversy arises from political, ethical, economic, and health considerations regarding the fluoridation of public water supplies. For deprived groups in both maturing and matured countries, international and national agencies and dental associations across the world support the safety and effectiveness of water fluoridation. Proponents of water fluoridation see it as a question of public health policy and equate the issue to vaccination and food fortification, citing significant benefits to dental health and minimal risks. In contrast, opponents of water fluoridation view it as an infringement of individual rights, if not an outright violation of medical ethics, on the basis that individuals have no choice in the water that they drink, unless they drink more expensive bottled water. A small minority of scientists have challenged the medical consensus, variously claiming that water fluoridation has no or little cariostatic benefits, may cause serious health problems, is not effective enough to justify the costs, and is pharmacologically obsolete.

<span class="mw-page-title-main">Waterborne disease</span> Diseases caused by pathogenic microorganisms transmitted by waters

Waterborne diseases are conditions caused by pathogenic micro-organisms that are transmitted by water. These diseases can be spread while bathing, washing, drinking water, or by eating food exposed to contaminated water. They are a pressing issue in rural areas amongst developing countries all over the world. While diarrhea and vomiting are the most commonly reported symptoms of waterborne illness, other symptoms can include skin, ear, respiratory, or eye problems. Lack of clean water supply, sanitation and hygiene (WASH) are major causes for the spread of waterborne diseases in a community. Therefore, reliable access to clean drinking water and sanitation is the main method to prevent waterborne diseases.

<span class="mw-page-title-main">Arsenic contamination of groundwater</span> Form of water pollution

Arsenic contamination of groundwater is a form of groundwater pollution which is often due to naturally occurring high concentrations of arsenic in deeper levels of groundwater. It is a high-profile problem due to the use of deep tube wells for water supply in the Ganges Delta, causing serious arsenic poisoning to large numbers of people. A 2007 study found that over 137 million people in more than 70 countries are probably affected by arsenic poisoning of drinking water. The problem became a serious health concern after mass poisoning of water in Bangladesh. Arsenic contamination of ground water is found in many countries throughout the world, including the US.

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 variability and intensity of rainfall as a result of climate change is expected to produce both more severe droughts and flooding, with potentially serious consequences for water supply and for pollution from combined sewer overflows. Droughts are likely to particularly affect the 66 percent of Americans whose communities depend on surface water. As for drinking water quality, there are concerns about disinfection by-products, lead, perchlorates, PFAS and pharmaceutical substances, but generally drinking water quality in the U.S. is good.

<span class="mw-page-title-main">Water fluoridation by country</span>

Water fluoridation is the controlled addition of fluoride to a public water supply to reduce tooth decay, and is handled differently by countries across the world. Fluoridated water contains fluoride at a level that is proven effective for preventing cavities; this can occur naturally or by adding fluoride. Fluoridated water 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. Typically, a fluoridated compound is added to drinking water, a process that in the U.S. costs an average of about $1.32 per person-year. Defluoridation is needed when the naturally occurring fluoride level exceeds recommended limits. In 2011, the World Health Organization suggested a level of fluoride from 0.5 to 1.5 mg/L, depending on climate, local environment, and other sources of fluoride. Bottled water typically has unknown fluoride levels.

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 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. The Safe Drinking Water Act requires the US EPA to set standards for drinking water quality in public water systems. Enforcement of the standards is mostly carried out by state health agencies. States may set standards that are more stringent than the federal standards.

<span class="mw-page-title-main">Water fluoridation in the United States</span>

Water fluoridation in the United States is common amongst most states. As of May 2000, 42 of the 50 largest U.S. cities had water fluoridation. On January 25, 1945, Grand Rapids, Michigan, became the first community in the United States to fluoridate its drinking water for the intended purpose of helping to prevent tooth decay.

<span class="mw-page-title-main">WASH</span> Water, sanitation and hygiene services

WASH is a sector in development cooperation or within local governments that provides water, sanitation, and hygiene services to people. The main purposes of providing access to WASH services include achieving public health gains, implementing the human right to water and sanitation, reducing the burden of collecting drinking water for women, and improving education and health outcomes at schools and health facilities. Access to WASH services is an important component of water security. Universal, affordable, and sustainable access to WASH is a key issue within international development and is the focus of the first two targets of Sustainable Development Goal 6. Targets 6.1 and 6.2 aim for equitable and accessible water and sanitation for all. In 2017, it was estimated that 2.3 billion people live without basic sanitation facilities, and 844 million people live without access to safe and clean drinking water. The acronym WASH is used widely by non-governmental organizations and aid agencies in developing countries.

<span class="mw-page-title-main">Water issues in developing countries</span> Water issues and problems in developing countries are diverse and serious

Water issues in developing countries include scarcity of drinking water, poor infrastructure for water and sanitation access, water pollution, and low levels of water security. Over one billion people in developing countries have inadequate access to clean water. The main barriers to addressing water problems in developing nations include poverty, costs of infrastructure, and poor governance. The effects of climate change on the water cycle can make these problems worse.

<span class="mw-page-title-main">Groundwater pollution</span> Ground released seep into groundwater

Groundwater pollution occurs when pollutants are released to the ground and make their way into groundwater. This type of water pollution can also occur naturally due to the presence of a minor and unwanted constituent, contaminant, or impurity in the groundwater, in which case it is more likely referred to as contamination rather than pollution. Groundwater pollution can occur from on-site sanitation systems, landfill leachate, effluent from wastewater treatment plants, leaking sewers, petrol filling stations, hydraulic fracturing (fracking) or from over application of fertilizers in agriculture. Pollution can also occur from naturally occurring contaminants, such as arsenic or fluoride. Using polluted groundwater causes hazards to public health through poisoning or the spread of disease.

Water supply and sanitation in Mali is characterized by serious challenges. Unclean water can lead to many diseases that are potentially fatal. Water supply issues lead to a variety of issues throughout the country.

<span class="mw-page-title-main">Water supply and sanitation in Laos</span>

Laos is a nation with plentiful surface water and broad rivers, but outside of cities, water sanitation and accessibility infrastructure is sparse. Few improvements have been made since the end of the Laotian Civil War in 1975, especially compared to peer nations such as Thailand. By 2015, 76% of Laotians nationwide were estimated to have access to “improved” water, while 71% were estimated to have access to “improved” sanitation.

Lesotho is a mountainous and fairly 'water-rich country', but suffers from a lack of clean drinking water due to inadequate sanitation. In recent decades, with the construction of dams for the Lesotho Highlands Water Project (LHWP), Lesotho has become the main provider of water to parts of northern South Africa. Despite the economic and infrastructure development occasioned by the LHWP, waterborne diseases are common in the country and the infant mortality rate from them is high. In 2017, a project to improve the rural water supply in the Lesotho Lowlands was funded by the Global Environment Facility and the African Development Bank, and is ongoing.

<span class="mw-page-title-main">Wellhead protection program</span> US groundwater contamination law

The Wellhead Protection Program in the 1986 amendments to the Safe Drinking Water Act requires states to protect underground sources of drinking water from contaminants that may adversely affect human health. Over half of the U.S. population relies on groundwater for drinking water However, residential, municipal, commercial, industrial, and agricultural activities can all contaminate groundwater. In the event of contamination, a community's drinking water supply can develop poor quality or be lost altogether. Groundwater contamination occurs from products such as oil, chemicals, gasoline, or other toxic substances to infiltrate groundwater. These products can travel through soil and seep into the groundwater; this process can occur through landfills, septic tanks, mining sites, fertilization, etc. Groundwater contamination might not be detected for a long period of time and health problems can occur from drinking contaminated water. Cleanup of a contaminated underground source of drinking water may be impossible or so difficult it costs thousands or millions of dollars. The U.S. Congress requiring Wellhead Protection Programs by 42 U.S.C. § 300h–7 in the Safe Drinking Water Act applied the concept that it is better to prevent groundwater contamination than try to remediate it. U.S. Congress by 42 U.S.C. § 300h–7 requires identification of the areas that need implementation of control measures in order to protect public water supply wells from contamination as "wellhead protection areas". Communities can use the police power established by the Tenth Amendment to the U.S. Constitution to enforce zoning and subdivision regulations to protect drinking water sources. Thereby communities can direct development away from areas that would pose a threat to drinking water sources.

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