There are six degrees of mikvaot, each superior to the other. The water of pools [smaller than 40 seah] if an unclean person drank of it and then a clean person drank of it, he becomes unclean; If an unclean person drank of it and then drew water from it in a clean vessel, [the vessel] becomes unclean; If an unclean person drank of it and then a loaf of terumah fell in: If he washed [his hands] in it, it becomes unclean; But if he did not wash [his hands] in it, it continues clean.

If one drew water from it in an unclean vessel and then a clean person drank [out of the pit], he becomes unclean. If one drew water [from it] in an unclean vessel and then drew water from it in a clean vessel, it becomes unclean. If one drew water [from it] in an unclean vessel and a loaf of terumah fell in: If he washed [his hands] in it, it becomes unclean; But if he did not wash [his hands] in it, it is clean.

If unclean water fell into it and a clean person drank of it, he becomes unclean. If unclean water fell into it and then water was drawn from it in a clean vessel, it becomes unclean. If unclean water fell into it and a loaf of terumah fell in: If he washed [his hands] in it, it becomes unclean; But if he did not wash [his hands] in it, it is clean. Rabbi Shimon says: it becomes unclean whether he washed in it or whether he did not wash in it.

If a corpse fell into it or an unclean person walked in it, and a clean person drank of it, he is clean. The same rule applies to the water of pools, the water of cisterns, the water of ditches, the water of caverns, the water of rain flows which have stopped, and mikvehs of less than forty seahs. They are all clean during the time of rain; When the rain has stopped those near to a city or to a road are unclean, and those distant remain clean until the majority of people pass [that way].

When do they become clean?Bet Shammai say: when their contents have been increased [by more than the original quantity] and they overflow. Bet Hillel say: when their contents have been increased [by more than their original quantity] even if they do not overflow. Rabbi Shimon says: when they overflow although their contents have not been so increased. [These] are valid [for preparing dough] for hallah and for the washing of the hands.

Superior to such [water] is the water of rain flows which have not stopped. If an unclean person drank of it and then a clean person drank of it, he is clean. If an unclean person drank of it and water was then drawn from it in a clean vessel, it is clean. If an unclean person drank of it and a loaf of terumah fell in, even if he washed his hand in it, it is clean. If one drew water from it in an unclean vessel and then a clean person drank [out of the pool], he is clean. If one drew water from it in an unclean vessel and a loaf of terumah fell [into the pool], even if he washed his hands in it, it is clean. If unclean water fell into it and a clean person drank of it, he is clean. If unclean water fell into it and one drew water from it in a clean vessel, it is clean. If unclean water fell into it and a loaf of terumah fell in, even if he washed his hands in it, it is clean. [All such water] is valid for terumah and for the washing of the hands.

Superior to such [water] is [the water of] the mikveh containing forty seahs, for in it people may immerse themselves and immerse other [things]. Superior to such [water] is [the water of] a spring whose own water is little but has been increased by a greater quantity of drawn water. It is equivalent to the mikveh in as much as it may render clean by standing water, and to an [ordinary] spring in as much as one may immerse in it whatever the quantity of its contents.