Water supply is the process of self-provision or provision by third parties of water of various qualities to different users. Municipal water supply is so far limited to public water supply. Typically water supply networks deliver a single quality of water, whether it is to be used for drinking, washing or landscape irrigation; Water supply systems get water from a variety of locations, including groundwater (aquifers), surface water (lakes and rivers), and the sea through the desalinated. The water is then, in most cases, purified, disinfected through chlorination. Treated water then either flows by gravity or is pumped to reservoirs, which can be elevated such as water towers or on the ground reservoirs distribution. Water supply service quality has many dimensions: continuity; water quality; pressure; and the degree of responsiveness of service providers to customer complaints.
Need for water purificationEdit
In 2004 about 3.5 billion people worldwide (54% of the global population) had access to piped water supply through house connections. Another 1.3 billion (20%) had access to safe water through other means than house connections, including standpipes, protected springs and protected wells. Finally, more than 1 billion people (16%) did not have access to safe water, meaning that they have to revert to unprotected wells or springs, canals, lakes or rivers to fetch water. Both an adequate amount of water and adequate water quality are essential for public health and hygiene. Waterborne diseases are among the leading causes of morbidity and mortality in developing countries. For example, an estimated 900 million people suffer (and approximately 2 million die) from water-related diarrhoeal illnesses each year. At least 17 percent of the total burden of human diseases in many developing countries can be attributed to diarrhea and infestations by intestinal worms. The most common waterborne diseases are diarrhea, typhoid and cholera.
Drinking water is water that is intended to be ingested by humans. Water of sufficient quality to serve as drinking water is termed potable water whether it is used as such or not. Although many fresh water sources are utilized by humans, some contain disease vectors or pathogens and cause long-term health problems if they do not meet certain water quality guidelines. As of the year 2006 (and pre-existing for at least three decades), there is a substantial shortfall in availability of potable water, primarily arising from overpopulation in lesser developed countries. As of the year 2000, 37 percent of the populations of lesser developed countries did not have access to safe drinking water. Implications for disease propagation are significant. Many nations have water quality regulations for water sold as drinking water. The World Health Organization sets international standards for drinking water.
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 - usually through chlorination - or it may need to undergo treatment, especially in the case of surface water.