I pay a monthly fee to use the local men’s mikva. Quite frequently the heating system for the mikva doesn’t work and the water in the mikva as well as the showers in the mikva are quite cold. Recently, when I paid my monthly fee for the mikva, the machine returned me too much change. Must I return the excess change or may I keep it since perhaps the mikva owes me money for all the times when they failed to provide me with warm showers?
We will address your question based on your assumption that the money in the machine belongs to the proprietor of the mikva and when the machine returned you too much money the one who lost is the proprietor of the mikva. This is not a simple matter and requires discussion on its own. However, in many cases that will be the case so we will assume so for this discussion.
In order to arrive at the halacha, we first have to understand what you are paying for when you pay for use of the mikva. The Pischei Choshen (Sechirus Chapter 4, footnote 1) maintains that one is purchasing the right to use the facilities. He argues that one cannot consider it to be a rental since one does not rent a specific place. Thus, according to his view, the fee you pay is classified as payment for a purchase.
However, his reason for classifying it as a purchase can be refuted.
First of all, this issue is discussed by the Gemara and Rishonim. The Gemara (Bava Metsiyo 48A) discusses paying for use of a Roman bathhouse and Tosafos writes that the payment is for renting the mikva.
The argument that it cannot be a rental is also difficult since, while it is true that many people use the mikva at the same time, that does not preclude classifying your relationship as being that of a renter since often more than one person rents a facility. The fact that there is no specific place that is yours also does not pose a problem since, again, there can be joint tenants. There does not have to be a part which belongs to one tenant. It suffices if the property that is rented by all the joint tenants is clearly defined.
Moreover, even if so many people rent a facility that when one divides the value of the entire property among all the renters, each renter would own less than a pruto of the facility, it is still considered to be a rental! This can be proven from the Gemara (Succa 27B) that derives from a pasuk that the entire Jewish nation could fulfill the mitzvah of Succa by sitting in a single succa. From this pasuk the Gemara derives that even if one just borrows use (See Rashi cv kol that each person’s ownership is that of a borrower) of a succa he fulfills the mitzvah and one does not need to own the succa. Since borrowing and renting are halachically equivalent as far as issues of ownership are concerned, we see that one is classified as a renter even if the value of his ownership is less than a pruto.
There are many poskim (Eimek Hamishpot (vol 5, page 140), Minchas Tzvi (Sechirus siman 2 page 92) , Sefas Hachoshen (Rav Etach), Halacha Beruro) who agree with the view that your payment was for rental of the mikva. One of these opinions (Sefas Hachoshen) however, maintains that since the mikva also allows one to take a shower and the water that one uses in taking a shower is not reusable, your payment to the mikva is both a rental of the mikva and a purchase of the water you use to take a shower.
However, perhaps that was true only in days gone by in Israel where people went to the mikva in order to take a hot shower. However, nowadays where people have hot water at home and may not go to the mikva in order to take a hot shower, it may be that the entire payment is for rental of the mikva and a hot shower is a bonus that is given to users of the mikva. This is especially true in those mikvas where one is required to shower before using the mikva for sanitary purposes since it is not the customer who wants the shower but the proprietor.
Having established that you are a renter, we can discuss whether you are entitled to a refund of part of your fee since the mikva did not provide hot water.
The Mishna (Bava Metsiyo 78A) writes that if one rented a donkey and the donkey became blind or lame making the use of the donkey much more difficult, the renter cannot ask the owner to provide him with a different donkey. Most Rishonim, and that is the opinion of the Rambam and Shuchan Aruch, understand further that the renter has to pay the full rental price and is not entitled to a reduction. The logic is that when one rents something he is a temporary owner and Hashem sent him the problem. While it is the owner’s obligation to repair the mikva he, nevertheless, does not suffer a monetary loss from the renter’s impaired ability to use the donkey or mikva as long as the owner attends to the repair in a timely manner.
An important distinction must be noted. In case a person rented a facility for a number of uses and one or more of these cannot be accomplished due to damages in the rental, then the price is reduced. The source for this is responsa of the Maharam of Padua (Responsa 39).
In his situation, a person rented a store for the express purpose of lending money with interest. At first Jews were allowed to lend money with interest both with and without taking collateral. Afterwards, the government forbade lending without collateral which severely cut down the amount of loans the renter could extend, adversely affecting his income. The Maharam ruled that the renter is entitled to a reduced price since one of the uses has been removed. He argues that a use which no longer exists is equivalent to the death of the donkey. Just like a renter does not have to pay rent for the period following the death of the donkey so too he does not need to pay the share of the rental fee which covers the use which has been discontinued.
This is often important when people rent apartments and a room becomes unusable due to leaks or mold etc. Since a room became unavailable the renter is entitled to a reduction in the rent. This is also true if people pay for the mikva in order to both immerse themselves and to take a shower. If due to the lack of hot water one could not shower, he would be entitled to a reduction since one use was unavailable. However, where people don’t go to the mikva for the shower and only pay for immersing themselves, this is not the case.
In conclusion: If people in your area go mainly to immerse themselves and the mikva was repaired in a timely manner you are not entitled to a reduced fee for those days when the mikva was cold since you could still immerse yourself. Therefore, the excess change you received must be returned to the proprietor of the mikva. However if people also go for the shower then you may keep the excess change if it is less than or equal to your loss from not being able to take a shower. However, this needs to be evaluated by a Rov who is familiar with the mikva.