a truck in kolhapur, maharashtra, india shipot, a common source of drinking water in dzyhivka, ukraine main articles: drinking water § global access, wash, and water issues in developing countries this section is an excerpt from drinking water § global access. 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.": 2 in 1990, only 76 percent of the global population had access to drinking water. by 2015 that number had increased to 91 percent. 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. 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. by 2015, 5.2 billion people representing 71% of the global population used safely managed drinking water services. 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. estimates suggest that at least 25% of improved sources contain fecal contamination. 1.8 billion people still use an unsafe drinking water source which may be contaminated by feces. this can result in infectious diseases, such as gastroenteritis, cholera, and typhoid, among others. 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. safe drinking water is an environmental health concern. bottled water is sold for public consumption in most parts of the world. health aspects outbreaks of diseases due to contaminated water supply 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: in 1854, a cholera outbreak in london's soho district was identified by john snow as originating from contaminated water from the broad street pump. this can be regarded as a founding event of the science of epidemiology. in 1987, a cryptosporidiosis outbreak is caused by the public water supply of which the filtration was contaminated, in western georgia in 1993, milwaukee cryptosporidium outbreak in 1998, an outbreak of typhoid fever in northern israel, which was associated with the contaminated municipal water supply in 1997, 369 cases of cryptosporidiosis occurred, caused by a contaminated fountain in the minnesota zoo. most of the sufferers were children in 1998, a non-chlorinated municipal water supply was blamed for a campylobacteriosis outbreak in northern finland in 2000, a gastroenteritis outbreak that was brought by a non-chlorinated community water supply, in southern finland in 2000, an e. coli outbreak occurred in walkerton, ontario, canada. seven people died from drinking contaminated water. hundreds suffered from the symptoms of the disease, not knowing if they too would die. in 2004, contamination of the community water supply, serving the bergen city centre of norway, was later reported after the outbreak of waterborne giardiasis in 2007, contaminated drinking water was pinpointed which had led to the outbreak of gastroenteritis with multiple aetiologies in denmark examples of chemical contamination include: in 1988, many people were poisoned in camelford, when a worker put 20 tonnes of aluminium sulphate in the wrong tank. in 1993, a fluoride poisoning outbreak resulting from overfeeding of fluoride, in mississippi in 2019 oil for an electric transformer oil entered the water supply for the city of uummannaq in greenland. a cargo ship in harbour was able to maintain a minimum supply the city for two days until the mains supply was restored and flushing of all the pipework was started. history main article: history of water supply and sanitation wasserkunst and fountain from 1602 in wismar, germany. it's an example of pre-industrialization waterworks and fountain. 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. 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. the first screw-down water tap was patented in 1845 by guest and chrimes, a brass foundry in rotherham. 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. by country water supply and sanitation by countryafghanistanalgeriaangolaargentinaaustraliaazerbaijanbangladeshbelgiumbelizebeninbhutanboliviabrazilburkina fasocambodiacanadachilechinacolombiacosta ricacubademocratic republic of the congodenmarkdominican republicecuadoregyptel salvadorethiopiafrancegeorgiagermanyghanagreecegrenadaguatemalaguyanahaitihondurasindiaindonesiairaniraqirelandisraelitalyjamaicajapanjordankenyakuwaitlaoslebanonlesotholiberialibyamalaysiamalimexicomoroccomozambiquenamibianepalnetherlandsnew zealandnicaraguanigeriaomanpakistanpalestinepanamaparaguayperuphilippinesportugalrussiarwandasaudi arabiasenegalsierra leonesingaporesolomon islandssouth africasouth sudanspainsudansyriataiwantanzaniathailandtrinidad and tobagotunisiaturkeytuvaluugandaunited kingdomunited statesuruguayvenezuelavietnamyemenzambiazimbabwe society and culture lawsuits arizona v. california colorado river water conservation district v. united states kansas v. colorado tahoe-sierra preservation council, inc. v. tahoe regional planning agency wisconsin v. illinois wyoming v. colorado