Mikveh or mikvah (Hebrew: מִקְוֶה / מקווה‎, Modern: mīqve, lit., "a collection") is a bath used for the purpose of ritual immersion in Judaism to achieve ritual purity. Most forms of ritual impurity can be purified through immersion in any natural collection of water. However, some impurities, such as a zav, require "living water", such as springs or groundwater wells. Living water has the further advantage of being able to purify even while flowing, as opposed to rainwater which must be stationary to purify. The mikveh is designed to simplify this requirement, by providing a bathing facility that remains in contact with a natural source of water. In Orthodox Judaism, these regulations are steadfastly adhered to; consequently, the mikveh is central to an Orthodox Jewish community. Conservative Judaism also formally holds to the regulations. The existence of a mikveh is considered so important that a Jewish community is required to construct a mikveh even before building a synagogue, and must go to the extreme of selling Torah scrolls, or even a synagogue if necessary, to provide funding for its construction.

Mikveh - Wikipedia