Prologue: The Torah twice mentions the punishment of Kares associated with he who enters the Mikdash Tamai. Why is the punishment so severe?
Rav Aharon Lichtenstein ztl. explains that there are 2 types of aveiros. The first is a sin whose action is in of itself a repugnant action. The second when the Torah outlaws an act not because the act itself is a terrible one, but because its ramifications are so severe. It is to this latter category of sins which entering the Temple in an unclean state belongs. Although the Torah certainly considered the entrance itself as taboo, probably serious enough to deserve lashings, the severity of the act, as expressed by the punishment of excision (karet), is tied with the resulting defilement of the Temple. While in a strictly formal, halakhic sense, the air of the Temple can not acquire ritual impurity, nonetheless the entrance of an unclean person into the Temple "defiles the tabernacle." Thus, the Torah does not focus on the severity of the act itself, but rather on the metaphysical blemish it leaves on the Temple. A person must know that his actions, for good and bad, leave their mark. We need not necessarily understand that our actions have physiological consequences, but rather that on some metaphysical level, our deeds can either bolster the world we try and build for ourselves, or, God forbid, destroy it.
Washing the whole body in water: Showering AFTER the Mikva
Walking among the historical remains of the old city of Yirushalayim, one will find an inordinate amount of Mikvaos. These Mikvaos are easy to spot in that the staircases down to them are separated from the staircases up. The reason is clear – one who is Tamai must go down in order to immerse his whole body into the water. Until that time, he is Tamai. However, upon emerging from the water, he is Tahor (or at least awaiting Ha’Arev Shemesh) and would want to avoid contact with one going down in order to prevent himself from becoming Tamai.
What is interesting to note is while there are many Mikvaos throughout the ancient streets and under much of the old city, there do not seem to be other places where one emerging from the Mikvah could wash off. Is one permitted to wash off or Shower after using the Mikvah?
The Talmud (Shabbos 14a) identifies 18 Gezairos that were passed on the day that Beis Shammai outnumbered Beis Hillel in the academy. On that day, one of the Gezairos that was passed was that if one put a majority of his body into drawn water, he is still Tamai. Actually, the literal interpretation of the Gemara is not that he is still Tamai but rather that he would ruin (posel) the Terumah. The logic of the Takana was that people were going to the Mikva in caves – as described above. These cave often contained fetid waters and upon emerging from the Mikvah, the people would immediately douse themselves with clean waters in order to refresh from the dirty Mikvah water. This led people to the mistaken belief that it was not the Mikvah water that served to purify but rather the shower water thereafter. Concerned that the people might stop going to the Mikva entirely (See Rashi), the Rabbis instituted the gezaira in order to stop people from not using the Mikvah before eating Terumah.
Implicit in the Gezaira appears to be the notion that this concern should apply to all cases where Mikvah use is biblically mandated. In other words, every time someone uses the Mikvah, they cannot shower thereafter. To do so, would ruin the Tevilah and its practice. Indeed, the Mordechai (Shavuos second perek siman 750) cites the Raaviah who in turn quotes Rav Shmuel ben Rav Natronayee Gaon who speaks out against women going into the shower after using the Mikvah. Rav Shmuel Ben Natronayee goes so far as to invalidate the Tevilah in this situation. The Ohr Zaruah (338:4) concurs.
However, the Mordechai challenges this position of Rav Shmuel noting that the Gezaira was an invalidation OF THE TERUMAH not of the Tevilah. He adds that since a woman’s husband is “Chullin” and not “Terumah” she does not need to be concerned in this situation (See Chullin 31a). The Mordechai adds that the Maharam of Rothenberg agreed with this position as well.
The Piskei Tosafos (Niddah 130) note that one can certainly wash herself in hot water after going to the mikvah for the mikvaos were often freezing and her ability to heat herself afterward in the hot water was a necessity.
However, the Rema (Y.D. 201:75) cites the Mordechai and adds that the minhag, at least among Ashkenazic women is not to bathe or shower again based upon the position of Rabbeinu Shmuel ben Natronayee. The Gra (Y.D. 201:127) disagrees and notes that our women may shower right away afterwards.
How should one practice Halacha L’maaseh?
Rav Moshe Feinstein ztl. (Iggros Moshe Y.D. II:96) and Maran HaRav Schachter Slita (Ginas Egoz # 21) maintain that if possible a woman should be concerned for the Rema’s position and not shower until the next nightfall.
Rav Mordechai Willig Shlita (cited in R. Sobolofsky’s “The Laws and Concepts of Niddah) and Rav Wosner ztl. (Shut Shevet HaLevi V:125) maintain that a woman may shower once the couple has touched one another or done some action indicating that she is Tehorah.
Rav Shlomo Zalman Auerbach ztl is cited (See Rav Sobolofsky p. 304) as maintaining that as long as the woman does not go straight from the Mikvah to the shower, she has fulfilled the Rema. Accordingly, waiting until she showers at home would be enough.
Rav Ovadiah Yosef (Shut Yabia Omer VIII:19) notes that the Chumra here is a single opinion among the Rishonim and does not need to be followed unless one has a town custom to follow the practice. In fact he notes that those making Aliya do not need to follow it.
The other Poskim cited above all add that if it is hard for the woman for whatever reason, there is plenty of room for her to be Meikil. The Tzitz Eliezer (xi: 64) adds that if a woman is already asking, one should learn to be lenient with her as this is a monhag that the majority of Rishonim did not observe.
As far as those men who go to the mikvah, there is no need to worry about this Chumra as that Tevilah never carried this stringency with it.