Water supply is the provision of water by public utilities, commercial organisations, community endeavors or by individuals, usually via a system of pumps and pipes. Irrigation is covered separately.
Water is a transparent, tasteless, odorless, and nearly colorless chemical substance, which is the main constituent of Earth's streams, lakes, and oceans, and the fluids of most living organisms. It is vital for all known forms of life, even though it provides no calories or organic nutrients. Its chemical formula is H2O, meaning that each of its molecules contains one oxygen and two hydrogen atoms, connected by covalent bonds. Water is the name of the liquid state of H2O at standard ambient temperature and pressure. It forms precipitation in the form of rain and aerosols in the form of fog. Clouds are formed from suspended droplets of water and ice, its solid state. When finely divided, crystalline ice may precipitate in the form of snow. The gaseous state of water is steam or water vapor. Water moves continually through the water cycle of evaporation, transpiration (evapotranspiration), condensation, precipitation, and runoff, usually reaching the sea.
A public utility company is an organization that maintains the infrastructure for a public service. Public utilities are subject to forms of public control and regulation ranging from local community-based groups to statewide government monopolies.
Irrigation is the application of controlled amounts of water to plants at needed intervals. Irrigation helps to grow agricultural crops, maintain landscapes, and revegetate disturbed soils in dry areas and during periods of less than average rainfall. Irrigation also has other uses in crop production, including frost protection, suppressing weed growth in grain fields and preventing soil consolidation. In contrast, agriculture that relies only on direct rainfall is referred to as rain-fed or dry land farming.
In 2010, about 56% of the global population (5.9 billion people) had access to piped water supply through house connections or to an improved water source through other means than house, including standpipes, water kiosks, spring supplies and protected wells. However, about 13% (about 900 million people) did not have access to an improved water source and had to use unprotected wells or springs, canals, lakes or rivers for their water needs.
An improved water source is a term used to categorize certain types or levels of water supply for monitoring purposes. It is defined as a type of water source that, by nature of its construction or through active intervention, is likely to be protected from outside contamination, in particular from contamination with fecal matter.
A standpipe is a freestanding pipe fitted with a tap which is installed outdoors to dispense water in areas which do not have a running water supply to the buildings.
Water kiosks are booths for the sale of tap water. They are common in many countries of Sub-Saharan Africa. Water kiosks exist, among other countries, in Cameroon, Haiti, Kenya, Malawi, Tanzania and Zambia.
A clean water supply—in particular, water that is not polluted with fecal matter from lack of sanitation—is the single most important determinant of public health.[ citation needed ] Destruction of water supply and/or sanitation infrastructure after major catastrophes (earthquakes, floods, war, etc.) poses the immediate threat of severe epidemics of waterborne diseases, several of which can be life-threatening.
Sanitation refers to public health conditions related to clean drinking water and adequate 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 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, trachoma, to name just a few.
Public health has been defined as "the science and art of preventing disease, prolonging life and promoting human health through organized efforts and informed choices of society, organizations, public and private, communities and individuals". Analyzing the health of a population and the threats it faces is the basis for public health. The public can be as small as a handful of people or as large as a village or an entire city; in the case of a pandemic it may encompass several continents. The concept of health takes into account physical, psychological and social well-being. As such, according to the World Health Organization, it is not merely the absence of disease or infirmity.
Water supply systems get water from a variety of locations after appropriate treatment, including groundwater (aquifers), surface water (lakes and rivers), and the sea through desalination. The water treatment steps include, in most cases, purification, disinfection through chlorination and sometimes fluoridation. Treated water then either flows by gravity or is pumped to reservoirs, which can be elevated such as water towers or on the ground (for indicators related to the efficiency of drinking water distribution see non-revenue water). Once water is used, wastewater is typically discharged in a sewer system and treated in a sewage treatment plant before being discharged into a river, lake or the sea or reused for landscaping, irrigation or industrial use (see also sanitation).
An aquifer is an underground layer of water-bearing permeable rock, rock fractures or unconsolidated materials. Groundwater can be extracted using a water well. The study of water flow in aquifers and the characterization of aquifers is called hydrogeology. Related terms include aquitard, which is a bed of low permeability along an aquifer, and aquiclude, which is a solid, impermeable area underlying or overlying an aquifer. If the impermeable area overlies the aquifer, pressure could cause it to become a confined aquifer.
A lake is an area filled with water, localized in a basin, surrounded by land, apart from any river or other outlet that serves to feed or drain the lake. Lakes lie on land and are not part of the ocean, and therefore are distinct from lagoons, and are also larger and deeper than ponds, though there are no official or scientific definitions. Lakes can be contrasted with rivers or streams, which are usually flowing. Most lakes are fed and drained by rivers and streams.
A river is a natural flowing watercourse, usually freshwater, flowing towards an ocean, sea, lake or another river. In some cases a river flows into the ground and becomes dry at the end of its course without reaching another body of water. Small rivers can be referred to using names such as stream, creek, brook, rivulet, and rill. There are no official definitions for the generic term river as applied to geographic features, although in some countries or communities a stream is defined by its size. Many names for small rivers are specific to geographic location; examples are "run" in some parts of the United States, "burn" in Scotland and northeast England, and "beck" in northern England. Sometimes a river is defined as being larger than a creek, but not always: the language is vague.
In the United States, the typical single family home uses about 520 l (138 US gal) of water per day (2016 estimate) or 222 l (58.6 US gal) per capita per day. This includes several common residential end use purposes (in decreasing order) like toilet use, showers, tap (faucet) use, washing machine use, leaks, other (unidentified), baths, and dishwasher use. [ better source needed ]
The United States of America (USA), commonly known as the United States or America, is a country comprising 50 states, a federal district, five major self-governing territories, and various possessions. At 3.8 million square miles, the United States is the world's third or fourth largest country by total area and is slightly smaller than the entire continent of Europe. With a population of over 327 million people, the U.S. is the third most populous country. The capital is Washington, D.C., and the most populous city is New York City. Most of the country is located contiguously in North America between Canada and Mexico.
Residential water use includes all indoor and outdoor uses of drinking quality water at single-family and multifamily dwellings. These uses include a number of defined purposes such as flushing toilets, washing clothes and dishes, showering and bathing, drinking, food preparation, watering lawns and gardens, and maintaining swimming pools. Some of these end uses are detectable while others are more difficult to gauge.
A shower is a place in which a person bathes under a spray of typically warm or hot water. Indoors, there is a drain in the floor. Most showers have temperature, spray pressure and adjustable showerhead nozzle. The simplest showers have a swivelling nozzle aiming down on the user, while more complex showers have a showerhead connected to a hose that has a mounting bracket. This allows the showerer to hold the showerhead by hand to spray the water at different parts of their body. A shower can be installed in a small shower stall or bathtub with a plastic shower curtain or door. Showering is common in Western culture due to the efficiency of using it compared with a bathtub. Its use in hygiene is, therefore, common practice. A shower uses less water on average than a bath: 80 litres for a shower compared with 150 litres for a bath.
Water supply service quality has many dimensions: continuity; water quality; pressure; and the degree of responsiveness of service providers to customer complaints. Many people in developing countries receive a poor or very poor quality of service.
Service quality (SQ), in its contemporary conceptualisation, is a comparison of perceived expectations (E) of a service with perceived performance (P), giving rise to the equation SQ=P-E. This conceptualistion of service quality has its origins in the expectancy-disconfirmation paradigm.
Water quality refers to the chemical, physical, biological, and radiological characteristics of water. It is a measure of the condition of water relative to the requirements of one or more biotic species and or to any human need or purpose. It is most frequently used by reference to a set of standards against which compliance, generally achieved through treatment of the water, can be assessed. The most common standards used to assess water quality relate to health of ecosystems, safety of human contact, and drinking water.
A developing country is a country with a less developed industrial base and a low Human Development Index (HDI) relative to other countries. However, this definition is not universally agreed upon. There is also no clear agreement on which countries fit this category. A nation's GDP per capita compared with other nations can also be a reference point. In general, the United Nations accepts any country's claim of itself being "developing".
Continuity of water supply is taken for granted in most developed countries, but is a severe problem in many developing countries, where sometimes water is only provided for a few hours every day or a few days a week. It is estimated that about half of the population of developing countries receives water on an intermittent basis.
Drinking water quality has a micro-biological and a physico-chemical dimension. There are thousands of parameters of water quality. In public water supply systems water should, at a minimum, be disinfected—most commonly through the use of chlorination or the use of ultra violet light—or it may need to undergo treatment, especially in the case of surface water. For more details, please see the separate entries on water quality, water treatment and drinking water.
Water pressures vary in different locations of a distribution system. Water mains below the street may operate at higher pressures, with a pressure reducer located at each point where the water enters a building or a house. In poorly managed systems, water pressure can be so low as to result only in a trickle of water or so high that it leads to damage to plumbing fixtures and waste of water. Pressure in an urban water system is typically maintained either by a pressurised water tank serving an urban area, by pumping the water up into a water tower and relying on gravity to maintain a constant pressure in the system or solely by pumps at the water treatment plant and repeater pumping stations.
Typical UK pressures are 4–5 bar (60-70 PSI) for an urban supply.[ citation needed ] However, some people can get over eight bars or below one bar. A single iron main pipe may cross a deep valley, it will have the same nominal pressure, however each consumer will get a bit more or less because of the hydrostatic pressure (about 1 bar/10 m height). So people at the bottom of a 30-metre (100 ft) hill will get about 3 bars more than those at the top.
The effective pressure also varies because of the pressure loss due to supply resistance even for the same static pressure. An urban consumer may have 5 metres of 15 mm pipe running from the iron main, so the kitchen tap flow will be fairly unrestricted, so high flow. A rural consumer may have a kilometre of rusted and limed 22 mm iron pipe, so their kitchen tap flow will be small.
For this reason, the UK domestic water system has traditionally (prior to 1989) employed a "cistern feed" system, where the incoming supply is connected to the kitchen sink and also a header/storage tank in the attic. Water can dribble into this tank through a 12 mm pipe, plus ball valve, and then supply the house on 22 or 28 mm pipes. Gravity water has a small pressure (say ¼ bar in the bathroom) so needs wide pipes to allow for higher flows. This is fine for baths and toilets but is frequently inadequate for showers. A booster pump or a hydrophore is installed to increase and maintain pressure. For this reason urban houses are increasingly using mains pressure boilers ("combies") which take a long time to fill a bath but suit the high back pressure of a shower.
A great variety of institutions have responsibilities in water supply. A basic distinction is between institutions responsible for policy and regulation on the one hand; and institutions in charge of providing services on the other hand.
Water supply policies and regulation are usually defined by one or several Ministries, in consultation with the legislative branch. In the United States the United States Environmental Protection Agency, whose administrator reports directly to the President, is responsible for water and sanitation policy and standard setting within the executive branch. In other countries responsibility for sector policy is entrusted to a Ministry of Environment (such as in Mexico and Colombia), to a Ministry of Health (such as in Panama, Honduras and Uruguay), a Ministry of Public Works (such as in Ecuador and Haiti), a Ministry of Economy (such as in German states) or a Ministry of Energy (such as in Iran). A few countries, such as Jordan and Bolivia, even have a Ministry of Water. Often several Ministries share responsibilities for water supply.[ citation needed ]
In the European Union, important policy functions have been entrusted to the supranational level. Policy and regulatory functions include the setting of tariff rules and the approval of tariff increases; setting, monitoring and enforcing norms for quality of service and environmental protection; benchmarking the performance of service providers; and reforms in the structure of institutions responsible for service provision. The distinction between policy functions and regulatory functions is not always clear-cut. In some countries they are both entrusted to Ministries, but in others regulatory functions are entrusted to agencies that are separate from Ministries.[ citation needed ]
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Dozens of countries around the world have established regulatory agencies for infrastructure services, including often water supply and sanitation, in order to better protect consumers and to improve efficiency. Regulatory agencies can be entrusted with a variety of responsibilities, including in particular the approval of tariff increases and the management of sector information systems, including benchmarking systems. Sometimes they also have a mandate to settle complaints by consumers that have not been dealt with satisfactorily by service providers. These specialized entities are expected to be more competent and objective in regulating service providers than departments of government Ministries. Regulatory agencies are supposed to be autonomous from the executive branch of government, but in many countries have often not been able to exercise a great degree of autonomy.
In the United States regulatory agencies for utilities have existed for almost a century at the level of states, and in Canada at the level of provinces. In both countries they cover several infrastructure sectors. In many U.S. states they are called Public Utility Commissions. For England and Wales, a regulatory agency for water (OFWAT) was created as part of the privatization of the water industry in 1989. In many developing countries, water regulatory agencies were created during the 1990s in parallel with efforts at increasing private sector participation. (for more details on regulatory agencies in Latin America, for example, please see Water and sanitation in Latin America and the regional association of water regulatory agencies ADERASA.)
Many countries do not have regulatory agencies for water. In these countries service providers are regulated directly by local government, or the national government. This is, for example, the case in the countries of continental Europe, in China and India.[ dubious ]
Water supply service providers, which are often utilities, differ from each other in terms of their geographical coverage relative to administrative boundaries; their sectoral coverage; their ownership structure; and their governance arrangements.
Many water utilities provide services in a single city, town or municipality. However, in many countries municipalities have associated in regional or inter-municipal or multi-jurisdictional utilities to benefit from economies of scale. In the United States these can take the form of special-purpose districts which may have independent taxing authority. An example of a multi-jurisdictional water utility in the United States is WASA, a utility serving Washington, D.C. and various localities in the state of Maryland. Multi-jurisdictional utilities are also common in Germany, where they are known as "Zweckverbaende", in France and in Italy.
In some federal countries, there are water service providers covering most or all cities and towns in an entire state, such as in all states of Brazil and some states in Mexico (see Water supply and sanitation in Mexico). In England and Wales, water supply and sewerage is supplied almost entirely through ten regional companies. Some smaller countries, especially developed countries, have established service providers that cover the entire country or at least most of its cities and major towns. Such national service providers are especially prevalent in West Africa and Central America, but also exist, for example, in Tunisia, Jordan and Uruguay (see also water supply and sanitation in Uruguay). In rural areas, where about half the world population lives, water services are often not provided by utilities, but by community-based organizations which usually cover one or sometimes several villages.
Some water utilities provide only water supply services, while sewerage is under the responsibility of a different entity. This is for example the case in Tunisia. However, in most cases water utilities also provide sewer and sewage treatment services. In some cities or countries utilities also distribute electricity. In a few cases such multi-utilities also collect solid waste and provide local telephone services. An example of such an integrated utility can be found in the Colombian city of Medellín. Utilities that provide water, sanitation and electricity can be found in Frankfurt, Germany (Mainova), in Casablanca, Morocco and in Gabon in West Africa. Multi-utilities provide certain benefits such as common billing and the option to cross-subsidize water services with revenues from electricity sales, if permitted by law.
Water supply providers can be either public, private, mixed or cooperative. Most urban water supply services around the world are provided by public entities. As Willem-Alexander, Prince of Orange (2002) stated, "The water crisis that is affecting so many people is mainly a crisis of governance—not of water scarcity." The introduction of cost-reflective tariffs together with cross-subsidization between richer and poorer consumers is an essential governance reform in order to reduce the high levels of Unaccounted-for Water (UAW) and to provide the finance needed to extend the network to those poorest households who remain unconnected. Partnership arrangements between the public and private sector can play an important role in order to achieve this objective.
An estimated 10 percent of urban water supply is provided by private or mixed public-private companies, usually under concessions, leases or management contracts. Under these arrangements the public entity that is legally responsible for service provision delegates certain or all aspects of service provision to the private service provider for a period typically ranging from 4 to 30 years. The public entity continues to own the assets. These arrangements are common in France and in Spain. Only in few parts of the world water supply systems have been completely sold to the private sector (privatization), such as in England and Wales as well as in Chile. The largest private water companies in the world are Suez and Veolia Environnement from France; Aguas de Barcelona from Spain; and Thames Water from the UK, all of which are engaged internationally (see links to website of these companies below). In recent years, a number of cities have reverted to the public sector in a process called "remunicipalization".
90% of urban water supply and sanitation services are currently in the public sector. They are owned by the state or local authorities, or also by collectives or cooperatives. They run without an aim for profit but are based on the ethos of providing a common good considered to be of public interest. In most middle and low-income countries, these publicly owned and managed water providers can be inefficient as a result of political interference, leading to over-staffing and low labor productivity.
Ironically, the main losers from this institutional arrangement are the urban poor in these countries. Because they are not connected to the network, they end up paying far more per liter of water than do more well-off households connected to the network who benefit from the implicit subsidies that they receive from loss-making utilities.
The fact that we are still so far from achieving universal access to clean water and sanitation shows that public water authorities, in their current state, are not working well enough. Yet some are being very successful and are modelling the best forms of public management. As Ryutaro Hashimoto, former Japanese Prime Minister, notes: "Public water services currently provide more than 90 percent of water supply in the world. Modest improvement in public water operators will have immense impact on global provision of services."
Governance arrangements for both public and private utilities can take many forms (Kurian and McCarney, 2010).Governance arrangements define the relationship between the service provider, its owners, its customers and regulatory entities. They determine the financial autonomy of the service provider and thus its ability to maintain its assets, expand services, attract and retain qualified staff, and ultimately to provide high-quality services. Key aspects of governance arrangements are the extent to which the entity in charge of providing services is insulated from arbitrary political intervention; and whether there is an explicit mandate and political will to allow the service provider to recover all or at least most of its costs through tariffs and retain these revenues. If water supply is the responsibility of a department that is integrated in the administration of a city, town or municipality, there is a risk that tariff revenues are diverted for other purposes. In some cases, there is also a risk that staff are appointed mainly on political grounds rather than based on their professional credentials.
International standards for water supply system are covered by International Classification of Standards (ICS) 91.140.60.
Comparing the performance of water and sanitation service providers (utilities) is needed, because the sector offers limited scope for direct competition (natural monopoly). Firms operating in competitive markets are under constant pressure to out perform each other. Water utilities are often sheltered from this pressure, and it frequently shows: some utilities are on a sustained improvement track, but many others keep falling further behind best practice. Benchmarking the performance of utilities allows the stimulation of competition, establish realistic targets for improvement and create pressure to catch up with better utilities. Information on benchmarks for water and sanitation utilities is provided by the International Benchmarking Network for Water and Sanitation Utilities.
The cost of supplying water consists, to a very large extent, of fixed costs (capital costs and personnel costs) and only to a small extent of variable costs that depend on the amount of water consumed (mainly energy and chemicals). The full cost of supplying water in urban areas in developed countries is about US$1–2 per cubic meter depending on local costs and local water consumption levels. The cost of sanitation (sewerage and wastewater treatment) is another US$1–2 per cubic meter. These costs are somewhat lower in developing countries. Throughout the world, only part of these costs is usually billed to consumers, the remainder being financed through direct or indirect subsidies from local, regional or national governments (see section on tariffs).
Besides subsidies water supply investments are financed through internally generated revenues as well as through debt. Debt financing can take the form of credits from commercial Banks, credits from international financial institutions such as the World Bank and regional development banks (in the case of developing countries), and bonds (in the case of some developed countries and some upper middle-income countries).
Almost all service providers in the world charge tariffs to recover part of their costs. According to estimates by the World Bank the average (mean) global water tariff is US$0.53 per cubic meter. In developed countries the average tariff is US$1.04, while it is only U$0.11 in the poorest developing countries. The lowest tariffs in developing countries are found in South Asia (mean of US$0.09/m3), while the highest are found in Latin America (US$0.41/m3).Data for 132 cities were assessed. The tariff is estimate for a consumption level of 15 cubic meters per month. Few utilities do recover all their costs. According to the same World Bank study only 30% of utilities globally, and only 50% of utilities in developed countries, generate sufficient revenue to cover operation, maintenance and partial capital costs.
According to another study undertaken in 2006 by NUS Consulting, the average water and sewerage tariff in 14 mainly OECD countries excluding VAT varied between US$0.66 per cubic meter in the United States and the equivalent of US$2.25 per cubic meter in Denmark.However, water consumption is much higher in the US than in Europe. Therefore, residential water bills may be very similar, even if the tariff per unit of consumption tends to be higher in Europe than in the US.
A typical family on the US East Coast paid between US$30 and US$70 per month for water and sewer services in 2005.
In developing countries, tariffs are usually much further from covering costs. Residential water bills for a typical consumption of 15 cubic meters per month vary between less than US$1 and US$12 per month.
Water and sanitation tariffs, which are almost always billed together, can take many different forms. Where meters are installed, tariffs are typically volumetric (per usage), sometimes combined with a small monthly fixed charge. In the absence of meters, flat or fixed rates — which are independent of actual consumption — are being charged. In developed countries, tariffs are usually the same for different categories of users and for different levels of consumption.
In developing countries, the situation is often characterized by cross-subsidies with the intent to make water more affordable for residential low-volume users that are assumed to be poor. For example, industrial and commercial users are often charged higher tariffs than public or residential users. Also, metered users are often charged higher tariffs for higher levels of consumption (increasing-block tariffs). However, cross-subsidies between residential users do not always reach their objective. Given the overall low level of water tariffs in developing countries even at higher levels of consumption, most consumption subsidies benefit the wealthier segments of society.Also, high industrial and commercial tariffs can provide an incentive for these users to supply water from other sources than the utility (own wells, water tankers) and thus actually erode the utility's revenue base.
Metering of water supply is usually motivated by one or several of four objectives: First, it provides an incentive to conserve water which protects water resources (environmental objective). Second, it can postpone costly system expansion and saves energy and chemical costs (economic objective). Third, it allows a utility to better locate distribution losses (technical objective). Fourth, it allows suppliers to charge for water based on use, which is perceived by many as the fairest way to allocate the costs of water supply to users. Metering is considered good practice in water supply and is widespread in developed countries, except for the United Kingdom. In developing countries it is estimated that half of all urban water supply systems are metered and the tendency is increasing.
Water meters are read by one of several methods:
Most cities are increasingly installing Automatic Meter Reading (AMR) systems to prevent fraud, to lower ever-increasing labor and liability costs and to improve customer service and satisfaction.
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.
Examples of contamination include:
Examples of chemical contamination include:
Throughout history, people have devised systems to make getting and using water more convenient. Living in semi-arid regions, ancient Persians in the 1st millennium BC used qanat system to gain access to water in the mountains. Early Rome had indoor plumbing, meaning a system of aqueducts and pipes that terminated in homes and at public wells and fountains for people to use.
Until the Enlightenment era, little progress was made in water supply and sanitation and the engineering skills of the Romans were largely neglected throughout Europe. It was in the 18th century that a rapidly growing population fueled a boom in the establishment of private water supply networks in London. The Chelsea Waterworks Company was established in 1723 "for the better supplying the City and Liberties of Westminster and parts adjacent with water".Other waterworks were established in London, including at West Ham in 1743, at Lea Bridge before 1767, Lambeth Waterworks Company in 1785, West Middlesex Waterworks Company in 1806 and Grand Junction Waterworks Company in 1811.
The S-bend pipe was invented by Alexander Cummings in 1775 but became known as the U-bend following the introduction of the U-shaped trap by Thomas Crapper in 1880. The first screw-down water tap was patented in 1845 by Guest and Chrimes, a brass foundry in Rotherham.
In ancient Peru, the Nazca people employed a system of interconnected wells and an underground watercourse known as puquios. In Spain and Spanish America, a community operated watercourse known as an acequia, combined with a simple sand filtration system, provided potable water. Beginning in the Roman era a water wheel device known as a noria supplied water to aqueducts and other water distribution systems in major cities in Europe and the Middle East. London water supply infrastructure developed over many centuries from early mediaeval conduits, through major 19th-century treatment works built in response to cholera threats, to modern, large-scale reservoirs.
Water towers appeared around the late 19th century; as building height rose, and steam, electric and diesel-powered water pumps became available. As skyscrapers appeared, they needed rooftop water towers.
The technique of purification of drinking water by use of compressed liquefied chlorine gas was developed in 1910 by U.S. Army Major (later Brig. Gen.) Carl Rogers Darnall (1867–1941), professor of chemistry at the Army Medical School. Shortly thereafter, Major (later Col.) William J. L. Lyster (1869–1947) of the Army Medical Department used a solution of calcium hypochlorite in a linen bag to treat water. For many decades, Lyster's method remained the standard for U.S. ground forces in the field and in camps, implemented in the form of the familiar Lyster Bag (also spelled Lister Bag). Darnall's work became the basis for present day systems of municipal water purification.
Desalination appeared during the late 20th century, and is still limited to a few areas.
During the beginning of the 21st Century, especially in areas of urban and suburban population centers, traditional centralized infrastructure have not been able to supply sufficient quantities of water to keep up with growing demand. Among several options that have been managed are the extensive use of desalination technology, this is especially prevalent in coastal areas and in "dry" countries like Australia. Decentralization of water infrastructure has grown extensively as a viable solution including Rainwater harvesting and Stormwater harvesting where policies are eventually tending towards a more rational use and sourcing of water incorporation concepts such as "Fit for Purpose". Emirians have the highest per capita water consumption rate in the world, at 133 gallons.
The first documented use of sand filters to purify the water supply dates to 1804, when the owner of a bleachery in Paisley, Scotland, John Gibb, installed an experimental filter, selling his unwanted surplus to the public. The first treated public water supply in the world was installed by engineer James Simpson for the Chelsea Waterworks Company in London in 1829.The practice of water treatment soon became mainstream, and the virtues of the system were made starkly apparent after the investigations of the physician John Snow during the 1854 Broad Street cholera outbreak demonstrated the role of the water supply in spreading the cholera epidemic.
The Metropolis Water Act introduced regulation of the water supply companies in London, including minimum standards of water quality for the first time. The Act "made provision for securing the supply to the Metropolis of pure and wholesome water", and required that all water be "effectually filtered" from 31 December 1855.This legislation set a worldwide precedent for similar state public health interventions across Europe.
Permanent water chlorination began in 1905, when a faulty slow sand filter and a contaminated water supply led to a serious typhoid fever epidemic in Lincoln, England.Dr. Alexander Cruickshank Houston used chlorination of the water to stem the epidemic. His installation fed a concentrated solution of chloride of lime to the water being treated. The first continuous use of chlorine in the United States for disinfection took place in 1908 at Boonton Reservoir (on the Rockaway River), which served as the supply for Jersey City, New Jersey. Desalination appeared during the late 20th century, and is still limited to a few areas.
The technique of purification of drinking water by use of compressed liquefied chlorine gas was developed by a British officer in the Indian Medical Service, Vincent B. Nesfield, in 1903.U.S. Army Major Carl Rogers Darnall, Professor of Chemistry at the Army Medical School, gave the first practical demonstration of this in 1910. This work became the basis for present day systems of municipal water purification.
Water supply issues have specific adverse effects on women in developing nations. Women are often the primary family member responsible for providing water as well as collecting it. Inclusion of women in the design and implementation of water supply projects is an area of concern currently being addressed by multiple world organizations.
Water supply and sanitation in Colombia has been improved in many ways over the past decades. Between 1990 and 2010, access to improved sanitation increased from 67% to 82%, but access to improved water source's increased only slightly from 89% to 94%. In particular, coverage in rural areas lags behind. Furthermore, despite improvements, the quality of water and sanitation services remains inadequate. For example, only 73% of those receiving public services receive water of potable quality and in 2006 only 25% of the wastewater generated in the country underwent any kind of treatment.
Uruguay is the only country in Latin America that has achieved quasi-universal coverage of access to safe drinking water supply and adequate sanitation. Water service quality is considered good, with practically all localities in Uruguay receiving disinfected water on a continuous basis. 70% of wastewater collected by the national utility was treated. Given these achievements, the government's priority is to improve the efficiency of services and to expand access to sewerage, where appropriate, in areas where on-site sanitation is used.
This article was written in 2008 with partial updates at later dates, including most recently in 2011. Please update it further.
Water supply and sanitation in France is universal and of good quality. Salient features of the sector compared to other developed countries are the high degree of private sector participation using concession and lease contracts and the existence of basin agencies that levy fees on utilities in order to finance environmental investments. Water losses in France (26%) are high compared to England (19%) and Germany (7%).
Public water supply and sanitation in Germany is universal and of good quality. Some salient features of the sector compared to other developed countries are its very low per capita water use, the high share of advanced wastewater treatment and very low distribution losses. Responsibility for water supply and sanitation provision lies with municipalities, which are regulated by the states. Professional associations and utility associations play an important role in the sector. As in other EU countries, most of the standards applicable to the sector are set in Brussels. Recent developments include a trend to create commercial public utilities under private law and an effort to modernize the sector, including through more systematic benchmarking.
Access to at least basic water increased from 94% to 97% between 2000 and 2015; an increase in access to at least basic sanitation from 73% to 86% in the same period;
Costa Rica has made significant progress in the past decade in expanding access to water supply and sanitation, but the sector faces key challenges in low sanitation connections, poor service quality, and low cost recovery.
The Dominican Republic has achieved impressive increases in access to water supply and sanitation over the past two decades. However, the quality of water supply and sanitation services remains poor, despite the country's high economic growth during the 1990s.
Water supply and sanitation in Indonesia is characterized by poor levels of access and service quality. Over 40 million people lack access to an improved water source and more than 110 million of the country’s 240 million population has no access to improved sanitation. Only about 2% of people have access to sewerage in urban areas; this is one of the lowest in the world among middle-income countries. Water pollution is widespread on Bali and Java. Women in Jakarta report spending US$11 per month on boiling water, implying a significant burden for the poor.
Rapid improvements are being made in augmenting drinking water supply and sanitation in India, due to concerted efforts by the various levels of government and communities at improving coverage. The level of investment in water and sanitation, albeit low by international standards, has increased in size during the 2000s. For example, in 1980 rural sanitation coverage was estimated at 1% and reached 95% in 2018. Also, the share of Indians with access to improved sources of water has increased significantly from 72% in 1990 to 88% in 2008. At the same time, local government institutions in charge of operating and maintaining the infrastructure are seen as weak and lack the financial resources to carry out their functions. In addition, only two Indian cities have continuous water supply and according to an estimate from 2018 about 8% of Indians still lack access to improved sanitation facilities. A study by Water Aid estimated as many as 10 million Indians, or 5 percent of Indians living in urban areas, live without adequate sanitation. India comes in first place globally for having the greatest number of urban-dwelling inhabitants living without sanitation. India tops the urban sanitation crisis, has the largest amount of urban dwellers without sanitation, and the most open defecators(urban) with over 5 million people.
Water supply and sanitation in China is undergoing a massive transition while facing numerous challenges such as rapid urbanization, increasing economic inequality, and the supply of water to rural areas. Water scarcity and pollution also impact access to water.
Water supply and sanitation in Panama is characterized by relatively high levels of access compared to other Latin American countries. However, challenges remain, especially in rural areas.
Water supply is the process of providing water in a systematic way through installed pumps and pipe lines. Before water is provided to a specific area, it undergoes a process called sanitation to ensure that the quality of water received is safe for human consumption. The Philippines’ water supply system dates back to 1946 after the country achieved its independence. Government agencies, local institutions, non-government organizations, and other corporations are primarily in charge in the operation and administration of water supply and sanitation in the country.
Public water supply and sanitation in Denmark is characterized by universal access and generally good service quality. Some salient features of the sector in the Denmark compared to other developed countries are:
Water supply and sanitation in Zambia is characterized by achievements and challenges. Among the achievements are the creation of regional commercial utilities for urban areas to replace fragmented service provision by local governments; the establishment of a regulatory agency that has substantially improved the availability of information on service provision in urban areas; the establishment of a devolution trust fund to focus donor support on poor peri-urban areas; and an increase in the access to water supply in rural areas.
Drinking water supply and sanitation in Egypt is characterized by both achievements and challenges. Among the achievements are an increase of piped water supply between 1990 and 2010 from 89% to 100% in urban areas and from 39% to 93% in rural areas despite rapid population growth; the elimination of open defecation in rural areas during the same period; and in general a relatively high level of investment in infrastructure. Access to an at least basic water source in Egypt is now practically universal with a rate of 98%. On the institutional side, the regulation and service provision have been separated to some extent through the creation of a national Holding Company for Water and Wastewater in 2004, and of an economic regulator, the Egyptian Water Regulatory Agency (EWRA), in 2006.
A water tariff is a price assigned to water supplied by a public utility through a piped network to its customers. The term is also often applied to wastewater tariffs. Water and wastewater tariffs are not charged for water itself, but to recover the costs of water treatment, water storage, transporting it to customers, collecting and treating wastewater, as well as billing and collection. Prices paid for water itself are different from water tariffs. They exist in a few countries and are called water abstraction charges or fees. Abstraction charges are not covered in this article, but in the article on water pricing). Water tariffs vary widely in their structure and level between countries, cities and sometimes between user categories. The mechanisms to adjust tariffs also vary widely.
Water supply and sanitation in Tanzania is characterised by: decreasing access to at least basic water sources in the 2000s, steady access to some form of sanitation, intermittent water supply and generally low quality of service. Many utilities are barely able to cover their operation and maintenance costs through revenues due to low tariffs and poor efficiency. There are significant regional differences and the best performing utilities are Arusha and Tanga.
Water supply and sanitation in Kenya is characterised by low levels of access to water and sanitation, in particular in urban slums and in rural areas, as well as poor service quality in the form of intermittent water supply. Seasonal and regional water scarcity exacerbates the difficulty to improve water supply.
Water supply and sanitation in Italy is characterized by mostly good services at prices that are lower than in other European countries with similar income levels. For example, the average monthly residential water and sewer bill in Italy is 20 Euro compared to 31 Euro in France. According to the OECD, water in Italy has been underpriced for a long time. With about 240 liter per day, per capita water use for residential uses in Italy is higher than in Spain or in France, where it is about 160 liter per day. Water resources in Italy are distributed unevenly, with more abundant resources in the North and scarcer resources in the South. Most water withdrawals are for agriculture and industry, with only 18 percent of water withdrawals made for drinking water supply. About one third of the water withdrawn for municipal supply is not billed to the customers because of leakage, malfunctioning water meters and water theft.
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