In most developed nations water is piped to homes, and is available on tap. The provision of tap water requires a massive infrastructure of piping, pumps, and water purification works. The cost of tap water is a small fraction of bottled water, even though the same water supply that is used for drinking is also used for washing and flushing water closets.

The availability of clean tap water brings major public health benefits. Usually, the same administration that provides tap water is also responsible for the removal of waste water.

See also: Water resources, electrokinetics