2. [If] one drew [from it] with a tamei vessel and then a tahor person drank [from it], he becomes tamei. [If] one drew [from it] with a tamei vessel and then one drew [from it] into a tahor vessel, it becomes tamei. [If] one drew [from it] with a tamei vessel and then a loaf of terumah fell [into it] — if he rinsed [it], it becomes tamei; if he did not rinse [it], it [remains] tahor.

3. [If] tamei water fell [into it] and then a tahor person drank [from it], he becomes tamei. [If] tamei water fell [into it] and then one drew [from it] into a tahor vessel, it becomes tamei. [If] tamei water fell [into it] and then a loaf of terumah fell [into it] — if he rinsed [it], it becomes tamei; if he did not rinse [it], it [remains] tahor. R’ Shimon says: Whether he rinsed [it] or he did not rinse [it], it becomes tamei.

4. [If] a corpse fell into it or a tamei person walked through it, and then a tahor person drank [from it], he [remains] tahor. Water in waterholes, water in cisterns, water in ditches, water in caves, water in seeps that has ceased [seeping], and mikvaos that do not contain forty se’ah [are all alike]. During the rainy season they are all [deemed] tahor. When the rains cease, those near to a town or road are [deemed] tamei, but those that are distant are [deemed] tahor until [such a time that] there are many walkers.

5. When do they become purified? Beis Shammai say: When they are increased by a greater amount and they [also] overflow. Beis Hillel say: [If] they were increased by a greater amount, even though they did not overflow. R’ Shimon says: [If] they overflowed, even though they were not increased by a greater amount. They are fit for challah and for [ritual] rinsing of the hands.