A boil water advisory is a public health advisory given by government or health authorities to communities when a community's drinking water is, or could be, contaminated by pathogens. Public health is concerned with threats to the overall health of a community based on population health analysis. ... It has been suggested that Safe water be merged into this article or section. ... A pathogen or infectious agent is a biological agent that causes disease or illness to its host. ...

Under a boil water advisory, it is recommended that water be boiled for several minutes in advance of consumption or use, in order to kill off as much of the bacteria and viral contamination as possible. Boiling is the rapid vaporization of a liquid, which typically occurs when a liquid is heated to a temperature such that its vapor pressure is above that of the surroundings, such as air pressure. ...

A common cause is a loss of pressure due to a failure of a pumping station. While loss of pressure does not necessarily mean the water has been contaminated, it does mean that potential pathogenic materials in contact with water supply plumbing may be able to diffuse into the system and thus be carried to consumers. The normal pressure of the water supply system would prevent this inward diffusion, as any leaks would force contaminants away from the supply.

See also water supply. A water supply system provides water to the locations that need it. ...

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