Overflowing Mikvah: Is It Kosher?

Ask the Rov: The mikvah is full, and water overflows into the water channel during tevilah. Is that an issue?

By Rabbi Chaim Hillel Raskin – Rov of Anash in Petach Tikvah

For a mikvah to be kosher, the water must be stationary and not flowing (zochalin). If a mikvah has a crack in one of its walls and water is leaking out, the Mechaber rules that as long as 40 se’ah remain stationary below the crack, the mikveh is kosher. However, the Rama quotes a stringent view that the flow above invalidates the entire mikvah, and we follow this view l’chatchila.¹ (There is a third opinion that any leak that isn’t flowing like a river doesn’t invalidate, but we don’t rely on this opinion at all.²)

What about toiveling under the crack? Some say that the lenient opinion requires one to toivel specifically under the crack, while others argue that even the stringent view would allow toiveling below the crack.

The Tzemach Tzedek is lenient for toiveling below the crack when it contains over 40 se’ah and it is the majority of the mikvah’s water.³ Other poskim rule stringently and contend that the Tzemach Tzedek retracted his earlier psak.⁴ Some permit b’dieved a tevilah below the crack, but invalidate tevilah above the crack even b’dieved.⁵

If a mikvah is filled to the top and immersing in it causes the water to overflow, some poskim permit it since after he has fully entered the water, it stops overflowing.⁶ Yet, many others invalidate it, and one should be stringent l’chatchila.⁷

If water overflows into the hamshacha channel and then returns on its own back into the mikvah, it’s not a concern of zochalin.⁸ Similarly, if the water flows into the bor hashaka, many hold it’s not a concern.⁹

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From The Weekly Farbrengen by Merkaz Anash