History of water supply and sanitation
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Ancient age 
- See also Sanitation in the Indus Valley Civilization, Sanitation in Ancient Rome, and Traditional water sources of Persian antiquity.
During the Neolithic, man dug the first permanent water wells, from where vessels could be filled and carried by hand. The size of human settlements was largely dependent on nearby available water. Pit toilets and chamber pots were the only alternative to defecation in the open, until flush toilets became commonplace, which happened in Western cities in the mid-19th century. Devices such as shadoofs, and sakias have been used to lift water to ground level.
Throughout history people have devised systems to make getting and using water more convenient. The Indus Valley Civilization has early evidence of public water supply and sanitation. The Roman Empire had indoor plumbing, meaning a system of aqueducts and pipes that terminated in homes and at public wells and fountains for people to use. Rome and other nations used lead pipes, often unknowing about lead poisoning.
Persian Qanats have been used for water supply and cooling in the Middle East.
Middle and early modern age 
Pail closets, outhouses, and cesspits were used to collect human waste. The use of human waste as fertilizer was especially important in China and Japan, where cattle manure was less available. See toilets in Japan. After the adoption of gunpowder, municipal outhouses became an important source of raw material for the making of saltpeter in European countries.
In London, the contents of the city's outhouses were collected every night by commissioned wagons and delivered to the nitrite beds where it was sown into the special soil beds to produce earth rich in mineral nitrates. The nitrate rich-earth is then further processed to produce saltpeter, or potassium nitrate, an important ingredient in black powder.
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 trap was invented in 1775. Fire hydrants were introduced in the 18th and 19th century.
Industrial age 
The first screw-down water tap was patented in 1845. The germ theory of disease emphasized the need of clean water supply, separated from sewerage. The 1854 Broad Street cholera outbreak in London was a well-known case.
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.
Current development 
During the beginning of the 21st Century, especially in areas of urban and suburban population centres, 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".
Fresh water is an objective among the Millennium Development Goals.
See also 
- Firearms: A Global History to 1700, Kenneth Chase
- Instructions for the Manufacture of Saltpetre, Joseph LeConte, 1823-1901