tap water

water, obtained directly from a faucet or tap, that has not been purified, distilled, or otherwise treated.

Origin of tap water

First recorded in 1880–85

tap, tap bell, tap bolt, tap dance, tap pants, tap water, tap-dance, tap-in, tapa, tapadera, tapadero

Our own experiments have been made both with distilled water and tap-water with the advantage in favor of the latter.

The North American Slime-Moulds |Thomas H. (Thomas Huston) MacBride
The cell is usually filled with tap-water, and a period of rest after making up, generally speaking, improves the sensitiveness.

Response in the Living and Non-Living |Jagadis Chunder Bose
Thus, a shallow tin vessel, such as the lid of a biscuit box, may be levelled and filled with tap-water through a rubber hose.

Encyclopaedia Britannica, 11th Edition, Volume 5, Slice 3 |Various

tap water

water drawn off through taps from pipes in a house, as distinguished from distilled water, mineral water, etc