In today’s daf (Beitzah 18a-b), reference is made to the mitzvah of immersing in a mikvah where the Gemara raises the question of why immersion is not considered as self-repairing (מתקן כלי) which surely should be forbidden on Shabbat or Yom Tov?
The Gemara first answers by explaining that immersing in a mikvah may – at least on first glance – appear as if someone simply wishes to cool down on a hot day (nb. it should be noted that if someone does immerse in a kosher mikveh, such as the sea, with the intention to cool off, then this is considered to be a valid immersion). As such, it does not immediately appear as מתקן כלי.
The Gemara then responds by noting that while this may be a valid answer if the mikvah water is clean, what if it is not so clean? Surely in such a situation, immersing in a mikveh is considered as מתקן כלי. To this, Rav Nachman bar Yitzchak answers that there are occasions when someone is so hot that they are even prepared to cool off in not-so-clean water.
The Gemara then points out that this all may be true during the summer. But how about when someone immerses in a mikveh in the winter? Surely in such a situation an immersion should be considered as מתקן כלי?
Here too, Rav Nachman bar Yitzchak answers by stating there are occasions when someone may be so desperate to bathe that they would even do so in (the not-so-clean water during) winter.
There are clearly some interesting halachic lessons that can be drawn from this Gemara about the conditions of water to allow for a valid immersion. Nevertheless, when I read this Gemara, I am reminded of the מסירת נפש of those many generations of women and men who immersed in mikvaot in less-than-ideal conditions; when the water was freezing, or not-so-clean, in the sea, or where they lacked the privacy that they would have preferred, as well as how much credit should be given to those managing mikvaot today (nb. full disclosure – my wife Donna used to manage the Central London Mikveh which prided itself on its quality of service to those women who came to use the mikveh) – many of whom work incredibly hard to ensure that the water is warm and clean so that immersion is both a spiritually meaningful and physically pleasant experience.