Zav/Zavah

Zav and Zavah are states of ritual impurity in Judaism arising from abnormal bodily discharges; for men the state is termed zav, and for women it is termed zavah. The Jewish regulations and existence of these states have a biblical basis^[1][2], and further specification of these rules exists in the Jewish Oral Law; Orthodox Judaism views the Shulchan Aruch as being particularly authoritative on these matters, and it has extensive discussion about the subject. Normal menstruation is explicitly excluded from the biblical regulations concerning zavah^[3], and is treated with separate requirements known as niddah^[4]; the ejaculation of semen is also treated as being distinct from zav, and is given requirements known as keri^[5].

Additional recommended knowledge

Guide to balance cleaning: 8 simple steps

What is the Correct Way to Check Repeatability in Balances?

How to ensure accurate weighing results every day?

Biblical regulations

The biblical regulations specify that any abnormal discharge of bodily fluids would result in a person becoming ritually unclean^[6][7], and that seven days after the discharge had ceased, the person in question was required to wash their clothes, bathe in running water, and then make a sin offering and a whole offering, each involving a dove^[8][9][10]; only after the week's wait, the washing, and sacrifices, would the person become ritually clean once more. The state of uncleanliness was considered able to be transferred, such that if the person spat on another, or was touched by another, then the other person also became ritually unclean, although they could restore ritual cleanliness in a much simpler way, only having to wait until evening had come and then washing themselves in running water^[11].

Additionally, this uncleanliness was considered to have been spread onto anything that a person suffering from these discharges had sat on, rode, or lied upon^[12][13][14], and anyone, and their clothes, who subsequently sat on it, rode it, or lied upon it, would similarly become ritually unclean; people and objects which had acquired the state in this manner were again only treated as ritually unclean until the evening had come and they had been washed in running water^[15][16][17]. The ritual uncleanliness could also be transferred to earthen and wooden containers which the person suffering the discharges had touched; destruction of the earthen vessels afflicted in this way was required, but wooden ones could just be washed in order for them to be considered ritually clean again^[18].

The biblical text differentiates between abnormal menstruation^[19] and the other kinds of abnormal discharge^[20], although the regulations are essentially the same. According to textual scholars, the regulations concerning childbirth^[21], which have a similar 7 day waiting period before washing, and the sin and whole offerings, were originally suffixed to those concerning abnormal menstruation, but were later moved^[22]. Although the regulations clearly have a sanitary benefit in the light of modern medical knowledge, Biblical scholars see these regulations as having originally derived from taboos against contact with blood and semen, because they were considered to house life itself, and were consequently considered sacred^[23]; the seven day period is thought to exist to ensure that the abnormality has genuinely ceased, the sin offering is considered to have originally been made as an apology for violating the taboo^[24], and the whole offering is regarded as a later addition (before the Priestly Code was written)^[25].

Classical and Mediaeval Rabbinic literature

According to the Mishnah, the laws of zav/zavah only applied if the discharge in question had happened at least three times, whether thrice in one day, or over consecutive days^[26]. The Talmud adds the argument that normal menstruation and emission of semen differ from zavah and zav by being the reverse colours; it argues that red menstruation is normal, but any white discharge in women would be abnormal, and that normal emission of semen is white, but abnormality would be indicated by any red discharge.

In regard to the transmittability of zav/zavah, the Mishah argues that if a ritually clean person and a person suffering from an abnormal discharge both sat on an animal, or in a small boat, then the ritually clean person would become ritually unclean by doing so, regardless of how far apart they might sit^[27]; however, if two people shared a wobbly bench, and one of them was ritually unclean, it was the opinion of Judah haNasi that it wouldn't cause the other person to also gain ritual uncleanliness^[28].

By the classical era, a type of specially designed bath, known as a mikvah, was used for ritual washing; the mikvah is designed so that it is filled from a direct source of running water.

In Modern Judaism

Due to the destruction of the Temple in Jerusalem, Judaism regards the sacrificial regulations as being in abeyance; rabbinical tradition subsequently differentiated less and less between the regulations of zav/zavah and those for keri and niddah. In modern Orthodox Judaism, women who experience normal menstruation are required to obey the non-sacrificial regulations for zavah, namely that they must wash in a mikvah seven days after menstruation; for men, modern Orthodox Judaism treats any form of nocturnal emission as ritually unclean, and multiple cases of nocturnal emission, and any other discharge of semen that doesn't result from sexual activity, as zav, requiring washing in a mikvah one week later.

Conversely, Reform Judaism regards such regulations as anachronistic; adherants of Conservative Judaism take a view somewhere between these views.