Mikvaos 7:1-2

Mikvaos 7:1

Some things raise a mikvah(‘s water level) and don’t invalidate it; some things invalidate it and don’t raise it; some things neither raise it nor invalidate it. These things raise the mikvah and don’t invalidate it: snow, hail, frost, ice, salt and liquid mud. Rabbi Akiva said that Rabbi Yishmael once debated him, saying that snow doesn’t raise a mikvah. The people of Meidva testified in his name that he once told them to bring snow and prepare a mikvah with it lechatchila (ab initio). Rabbi Yochanan ben Nuri said that hailstones are like drawn water. These things raise a mikvah without invalidating it as follows: If a mikvah contained one seah less than the requisite 40 and a seah of one of these things fell in and completed the mikvah’s volume, it raises the mikvah without invalidating it.

Mikvaos 7:2

The following things invalidate a mikvah without raising its level to the necessary volume: drawn water regardless of whether it’s ritually clean or unclean, water that was used for pickling or for boiling, and grape-sediment wine before it ferments. These things invalidate a mikvah without raising its level as follows: If a mikvah contained a kortov less the requisite 40 seah and a kortov of one of these fell into it, it does not raise the volume of the mikvah. If there were three log of any of these things, it would invalidate the mikvah. Other liquids, fruit juice, brine, fish-pickling liquid, and grape-sediment wine that fermented sometimes raise a mikvah and sometimes don’t raise it, as follows: if a mikvah contained one less than the requisite 40 seah and a seah of one of these fell in, it doesn’t raise the mikvah to the requisite volume. However, if a mikvah contained a full 40 seah and a seah of one of these was put in, after which a seah was removed, the mikvah remains valid.