2. [If] a mikveh was measured and found lacking, all ritually pure foods that were prepared on its basis heretofore, whether in a private domain or in a public domain, are tamei. In regard to what are these words said? [Only] in [a case of] severe tumah. But in [a case of] mild tumah — for instance, one who ate tamei foods or drank tamei liquids, or one whose head and greater part of his body entered into drawn water, or three lugin of drawn water fell over his head and greater part of his body — [if] he went down to immerse himself, [but] there is a doubt whether he immersed himself or did not immerse himself; or [alternatively] even if he did immerse himself, there is a doubt whether there was forty se’ah [of water] or not; or [alternatively] there were two mikvaos, one containing forty se’ah and the other not, and he immersed himself in one of them but does not know in which one — these doubtful cases are [adjudged] tahor. R’ Yose declares him tamei. For R’ Yose says: Anything that has a chazakah of tumah is forever in its disqualified state until it is known that it became tahor. However, a doubtful case of whether he became tamei, or [whether he] caused tumah, is [adjudged] tahor.

3. [These are the cases of] doubt pertaining to drawn water that the Sages declared tahor: There is a doubt whether it fell [into the mikveh] or it did not fall; or [alternatively] even if it [definitely] did fall, there is a doubt whether there was forty se’ah [in the mikveh] or whether there was not; or [alternatively] there were two mikvaos, one containing forty se’ah and the other not, and it fell into one of them but he does not know into which one it fell. These doubtful cases are [adjudged] tahor, because there is something on which to depend. [But if] they each contained less than forty se’ah, and it fell into one of them and he does not know into which one it fell, this doubtful case is [adjudged] tamei, because there is nothing to depend on.

4. R’ Eliezer says: One reviis of drawn water disqualifies a mikveh at the beginning, but three lugin [when] on the surface of the water. But the Sages say: Both at the beginning and at the end the amount is three lugin.

5. [If] a mikveh has three hollows, each containing one log of drawn water, when it is known that forty se’ah of valid water had already fallen into [the mikveh] before they reached the third hollow, it is valid. Otherwise, it is invalid. But R’ Shimon declares it valid, because it is like one mikveh next to another mikveh.