Mikveh Before Yom Kippur

The Aish Rabbi Replies

Yes, going to the mikveh the day before Yom Kippur is a fairly universal practice brought in the classical sources. It is done both as a form of penitence and for spiritual purity. (This is particularly relevant to men to purify them from past emissions, but some women have the custom of going as well.) Large Jewish communities generally have mikveh's for men, which are used before holidays and by many before every Shabbat and by some daily. (Small communities often have the ladies’ mikveh available to men during daytime hours.)

No blessing is said on the immersion. It’s proper to do it before the Mincha prayers – i.e., before the viduy (confession) is recited at Mincha before the final meal. Last, it's sufficient to immerse one time (to attain purity from past emissions). Many have the custom of three times (for atonement), while the pious custom of 39 exists as well. (I would not recommend that practice unless your mikveh has a lifeguard.)

(Sources: Shulchan Aruch O.C. 606:4; Be’er Heitev 606:8; Mishna Berurah 606:21.)