Judaism

The Hebrew Bible has many rituals of purification relating to menstruation, childbirth, sexual relations, keri (nocturnal emission), unusual bodily fluids, skin disease, death, and animal sacrifices. Modern mainstream Judaism is based on a combination of the Hebrew Bible and Jewish oral law, which includes the Mishnah and Gemarrah (together comprising the Talmud) in addition to other rabbinic commentaries; this oral law further specifies regulations for ritual purity, including obligations relating to excretory functions, meals, and waking. The regulations of biblical and oral law generally prescribe a form of water-based ritual washing in Judaism for removal of any ritual impurity, sometimes requiring just washing of the hands, and at other times requiring full immersion; the oral law requires the use of living water for any ritual full immersion - either a natural river/stream/spring, or a special bath (a Mikvah) which is directly connected to one.

These regulations were variously observed by the ancient Israelites; contemporary Orthodox Jews and (with some modifications and additional leniencies) some Conservative Jews continue to observe the regulations, except for those tied to sacrifice in the Temple in Jerusalem, as the Temple no longer fully exists. These groups continue to observe many of the hand washing rituals. Of those connected with full ritual immersion; perhaps the quintessential immersion rituals still carried out are those related to nidda, according to which a menstruating woman must avoid contact with her partner, especially avoiding sexual contact, and may only resume contact after she has first immersed herself fully in a mikvah of living water seven days after her menstruation has ceased.

In December 2006 the Committee on Jewish Law and Standards of Conservative Judaism re-affirmed the traditional requirement that Conservative women ritually immerse following menstruation. In doing so, it adopted multiple opinions regarding details, including an opinion reaffirming traditional (Orthodox) practices and concepts, an opinion adapting certain leniencies including counting seven days from start of menstruation rather than its end, and an opinion reformulating the theological basis of the practice, basing it on concepts other than ritual purity. See the Niddah article for details. Classical ritual immersion and associated requirements are generally not observed by Reform Judaism or Reconstructionist Judaism, with the exception that both generally include immersion as part of the ritual for Conversion to Judaism, although Reform Judaism does not require it.

Tumat HaMet ("The impurity of death"), coming into contact with a human corpse, is considered the ultimate impurity, one which cannot be purified through the waters of the mikvah. Tumat HaMet required purification through sprinkling of the ashes of the Parah Adumah, the Red Heifer. However the law is inactive, since neither the Temple in Jerusalem nor the red heifer is currently in existence, though without the latter a Jewish person is forbidden to ascend to the site of the former. All are currently assumed to possess the impurity of death. However, someone who is a Kohen, one of the priestly class, is not allowed to intentionally come into contact with a dead body, nor approach too closely to graves within a Jewish cemetery.