After discussing a community’s responsibility to build a mikvah in the last chapter, we now begin the basic rules for creating a mikvah. Maintaining a mikvah also requires a high level of general competence and vigilance, as well as certain specific skills. We thus emphasize at the outset the words of Rav Shlomo Dichovsky (Techumin 16:112):
The building of mikva’ot today requires a combination of thorough halachic knowledge and specific engineering knowledge. Hence, very few people are regarded as competent in this critical field.
The Biblical Concepts
The Torah (Vayikra 11:36) states, “A ma’ayan (natural spring) or bor (cistern), a gathering of water, shall be pure.” The Torah mentions two bodies of water, a ma’ayan and a bor, neither of which can become tamei (ritually impure). The Sifra, commenting on this verse, understands that they cannot become tamei because they are themselves sources of purity. Hence, besides their own inability to become tamei, immersion in them purifies people and utensils that were tamei.
The Sifra further interprets the phrase “a gathering of water” (mikveh mayim) as alluding to a more general category derived from the cistern’s traits. A cistern unites waters that would have no connection to one another had they not flowed into it. Thus, their presence within the same “gathering of water” defines the cistern’s contents as one unit. A ma’ayan’s waters, on the other hand, are one body by virtue of the link to their source, so they can purify others even without gathering in one spot. Thus, the term mikvah (“gathering”) is routinely used in place of the term “bor, mikveh mayim” when describing cisterns and other pools of water that lack a natural source in the ground.
Differences Between a Mikvah and a Ma’ayan
The Mishnah (Mikva’ot 1:7-8) indicates two major differences between a mikvah and a ma’ayan. A ma’ayan is effective even though it is running water (zochalin), whereas a mikvah’s waters must be stationary (ashboren). Also, a mikvah must contain a minimum of forty sa’ah1We discuss the contemporary equivalent of this measurement later in the chapter. of water, while no such minimum exists for a ma’ayan.
Several other differences between a mikvah and a ma’ayan exist according to many, but not all, authorities. For example, discoloration of the water (shinui mar’eh) invalidates a mikvah, but the Shulchan Aruch (Yoreh Deah 201:28) rules that a ma’ayan is effective regardless of its water’s color.2See, however, Mishkenot Ya’akov 46 (cited as 44 by Pitchei Teshuvah, Yoreh Deah 201:20), who questions the Shulchan Aruch’s ruling. Some authorities also believe that concern for natan sa’ah v’natal sa’ah,3We discuss the concept of natan sa’ah v’natal sa’ah in detail in the fourth chapter of our discussion of mikva’ot. which relates to replacing the mikvah’s water in a halachically acceptable manner, does not apply to a ma’ayan.4Dagul Mer’vavah (commenting on Shach, Y.D.201:63), Teshuvot Beit Shlomo (Y.D. 2:59), and Maharsham (Teshuvot 1:44). Moreover, most Rishonim believe that the problem of mayim she’uvim (water poured from a vessel), which we explain in the next chapter, does not apply to a ma’ayan.5The Terumat Hadeshen (258) records that Ashkenazic communities in his time followed the strict view even though they knew it was the minority opinion. In practice, the Shulchan Aruch (Y.D. 201:15), and Aruch Hashulchan (Y.D. 201:106-110) rule that concern for mayim she’uvim does not apply to ma’ayanot. The Rama fundamentally agrees, but he nevertheless encourages following the strict opinion when doing so does not require tremendous effort. The Mishkenot Ya’akov (Y.D. 45; cited as 43 by Pitchei Teshuvah, Y.D. 201:28) urges us not to rely on the lenient view under any circumstances. For an analysis of the strict view, see the aforementioned Terumat Hadeshen.
Many Acharonim strongly encourage the use of a ma’ayan because these differences make it far easier to ensure that the ma’ayan remains acceptable for immersion.6Teshuvot Sh’eilat Ya’avetz (1:88), Lechem V’simlah (Lechem 201:3), and Teshuvot Arugat Habosem (Y.D. 2:210). Indeed, it was common in the time of the Rishonim to use ma’ayanot for tevilah because they avoid many halachic pitfalls (see Terumat Hadeshen 258). The Beit Shlomo (Y.D. 2:59), living in the late nineteenth century, records that “everyone knows” that most mikva’ot in his time were actually ma’ayanot. Even nowadays, there are some communities that adopt a stringency and supply the immersion pool with water from a well instead of tap water.7Rav Yirmiyah Katz (personal communication) explains that they dig a small hole (five to ten inches in diameter) deep underground (sometimes as deep as 500 feet). They insert a narrow pipe into this hole and then blow air into the pipe through a compressor. The resultant air pressure causes water to rise into the mikvah. See Teshuvot Minchat Yitzchak (7:76) and Teshuvot Mahari Shteif (142). Also see Teshuvot Seridei Eish (2:88) regarding a pump that brought spring water into a mikvah. Rav Yirmiyah Katz told me that the process of building a ma’ayan is frought with Halachic complexity. Since mistakes can easily be made, the mikvah’s supervising rabbi needs to personally oversee each step of the building process. Rav Katz told me that this is a labor-intensive project. This water might have the status of a ma’ayan. However, Teshuvot Minchat Yitzchak (7:76) states that one cannot simply regard this water as a ma’ayan. Rather, this water must also be made acceptable by hashakah and hamshacha. Rav Katz told me that some Rabbanim require zeri’ah as well (as indicated in Teshuvot Mahari Shteif 142) to make the water acceptable. First, we are concerned that separating spring water from its source removes its status as a ma’ayan, despite the water’s origins (see Shulchan Aruch, Y.D. 201:10).48See Shach (Y.D. 201:30) and Encyclopedia Talmudit (12:38-39) for a discussion of whether the spring water loses its status as a ma’ayan as soon as it is severed from its source, or only after it stops flowing and settles in one place. The Shach vehemently opposes the latter possibility. In addition, the Mishkenot Ya’akov (Y.D. 45, cited as 43 in Pitchei Teshuvah 201:28) further limits the application of the rules of ma’ayanot. He argues that most natural springs do not qualify as halachic ma’ayanot because the springs are located too close to rivers to be considered independent of them. Rav Moshe Feinstein (Teshuvot Igrot Moshe, Y.D. 3:64) accepts the Mishkenot Ya’akov’s claims.9In addition, the author of Teshuvot Divrei Chaim writes that we should not rely on ma’ayanot due to numerous concerns (introduction to Hilchot Mikva’ot 1:47). Finally, Ma’ayanot, Rav Katz reports, can easily be disqualified, so at most they should be used to supplement and further enhance the rainwater mikva’ot but never substitute for rainwater mikva’ot in the contemporary setting.
Water Quantity in a Ma’ayan
We have already mentioned that a ma’ayan does not need any minimum amount of water. However, Tosafot (Nazir 38a s.v. Bar) limit this leniency to the immersion of utensils (tevilat keilim).10In this context, tevilat keilim refers to immersing a utensil in order to purify its ritual impurity (as was commonly done before the Temple’s destruction, when the laws of ritual impurity were properly observed), but not to the immersion that we perform upon purchasing a utensil from a non-Jew. Immersing utensils that were owned by a non-Jew requires forty sa’ah according to all opinions. According to Tosafot, people must immerse in a minimum of forty sa’ah regardless of whether they are using a mikvah or a ma’ayan. The Ra’avad (Baalei Hanefesh, beginning of Sha’ar Hamayim) disagrees, requiring only that a ma’ayan contain enough water to cover the person immersing. The Rambam (Hilchot Mikva’ot 9:6) never mentions a requirement of forty sa’ah for people to use a ma’ayan, implying that he agrees with the Ra’avad.11For a conceptual analysis of this dispute, as well as its implication for the issue of zochalin (which we address later in this chapter), see Bei’ur Hagra (Y.D. 201:91). The Shulchan Aruch (Yoreh Deah 201:1) and almost all of its commentaries rule in accordance with Tosafot, but the Vilna Gaon (Bei’ur Hagra, Y.D. 201:6) defends the Rambam and Ra’avad’s view.12It is unclear whether the Vilna Gaon intends to actually rule in accordance with the Rambam and Ra’avad, or if he is simply noting that he finds their logic persuasive. See Aruch Hashulchan (Y.D. 201:10) for questionable situations where a poseik might rely on the Rambam and Ra’avad’s view.
Contemporary authorities debate how to measure forty sa’ah in liters. The opinions range from 648 liters to 964.3 liters.13For a complete discussion of the proper dimensions of a mikvah, see Mikveh Mayim (vol. 3 pp. 50-59). The Cheishev Ha’eifod (150:2) records that common practice is to build mikva’ot with at least one thousand liters, in order to avoid all doubts.14Rav Moshe Heinemann also mentioned this practice in a lecture to the Council of Young Israel Rabbis. Although this large quantity far exceeds any reasonable calculation of forty sa’ah, we already noted in the last chapter the common practice to be exceedingly stringent regarding hilchot mikva’ot.
Zochalin vs. Ashboren
We have already noted that mikvah water must be stationary. The Rama (Y.D. 201:2) rules that zochalin (water that flows outside a mikvah’s boundaries) invalidates the mikvah on a Biblical level.15Virtually all authorities agree with this position; see Encyclopedia Talmudit (12:20). Almost all Rishonim believe that the water need not flow in a torrent in order to be considered zochalin. Rather, even water flowing through a minor crack in the mikvah’s wall is defined as zochalin.
The Rashba (Torat Habayit, Sha’ar Hamayim, Sha’ar 2) believes, though, that in order to disqualify the mikvah, the water flow must at least be noticeable (zechilah hanikeret).16See Encyclopedia Talmudit 12:25 for other Rishonim who agree with the Rashba. The Shulchan Aruch (Y.D. 201:51) rules in accordance with this view. The Acharonim subsequently debate how to define a zechilah hanikeret, with quite a wide range of opinions on this matter (see Encyclopedia Talmudit 12:25-26 and Mikveh Mayim, vol. 2 pp. 23-31).
However, the Vilna Gaon (Bei’ur Hagra 201:96) appears to rule that even an indiscernible water flow (zechilah she’eina nikeret) disqualifies a mikvah.17The Vilna Gaon’s comments are somewhat cryptic. He appears to invalidate a mikvah with even the slightest zechilah, provided that the crack is low enough in the mikvah’s wall that less than forty sa’ah of water would remain if all the water above the crack would leak out. However, due to his cryptic language, some have argued that he does not actually disagree with the Shulchan Aruch. Rav Katz (Mikveh Mayim, vol. 2 pp. 35-41) dedicates an entire chapter to presenting the varying interpretations of this passage in the Bei’ur Hagra. Rav Chaim Soloveitchik (cited in Teshuvot Vehanhagot 1:513) vigorously supports this view. In practice, halachic authorities urge mikvah administrators to avoid even the slightest zechilah in a mikvah.18Teshuvot Ein Yitzchak (Y.D. 22), Teshuvot Achiezer (4:40), and Teshuvot Igrot Moshe (Y.D. 3:63). All these authorities agree that if a woman immersed in the mikvah without realizing that it contained a zechilah she’einah nikeret, then she need not immerse again. Once the zechilah is discovered, though, they recommend closing the mikvah until it is repaired. The Achiezer qualifies this position, adding that if a town Rav worries that his congregants will violate the prohibition against having relations with a nidah because they must wait until the repairs are completed in order to immerse, then the Rav may permit them to continue using the mikvah with the zechilah she’einah nikeret. Nevertheless, the mikvah should be repaired as soon as possible. Indeed, my cousin Rav Yosef Singer reports, regarding the mikvah on the Lower East Side of Manhattan, that Rav Moshe Feinstein insisted that there be not even a zechilah she’einah nikeret. Practically speaking, Rav Yirmiyah Katz (Mikveh Mayim, vol. 2 p. 31) notes that even the slightest zechilah eventually develops into a zechilah hanikeret and thus should not be ignored.
Filters
The use of filters in mikva’ot has aroused concern for zechilah. Rav Katz (in a speech to the Council of Young Israel Rabbis) noted that mikva’ot in Israel do not use filters due to this concern. In the United States, though, mikva’ot commonly use filters, so special care must be taken to avoid problems of zechilah.19For a thorough discussion of the use of filters in a mikvah, see Mikveh Mayim (vol. 2 pp. 67-84). Also see Rav Shmuel Wosner’s responsum in Techumin (22:445-446) and Rav Dov Brisman’s Teshuvot Shalmei Chovah (Y.D. 37). Rav Yirmiyah Katz told me (in 2003) that a new filter was recently developed in Montreal in order to avoid any problems of zechilah.
Concrete
The necessary care to prevent zechilot begins with the mikvah’s construction. For example, in previous generations mikvah walls were lined with clay or stone (Mikveh Mayim, vol. 1, p. 139). However, concrete was introduced in the early twentieth century because it reduces concern for zechilah. Rav Katz (Mikveh Mayim, vol. 3 p. 40) advises that mikvah builders should pour the concrete for the floor and walls simultaneously in order to strengthen the foundation and further reduce concern for zechilah. Indeed, avoiding zechilot comprises a key element of the practical engineering expertise and experience required for building mikva’ot today. Indeed, Rav Katz told me that it is vital that the supervising rabbi oversee the pouring of the cement. He added that it is insufficient for the supervising rabbi to make blueprints and rely on a contractor to follow directions on how to pour the cement. Rav Katz told me of the severe problems experienced by those communities that relied solely on the rabbi’s blueprint.
We should note that there was some debate regarding the halachic propriety of using concrete in the creation of a mikvah. However, it quickly became the universal practice to use concrete.20The primary concern was that the concrete walls and floor could stand on their own were they removed from the ground. Thus, perhaps they would be considered a vessel (kli), whereas a mikvah must consist of water resting in the ground, not in a vessel (ein tovlim b’keilim; see Shulchan Aruch, Y.D. 201:6). The Maharsham (Teshuvot 2:102) records that he initially prohibited constructing mikva’ot with concrete due to this concern. He partially retracted this objection after learning that people normally build by laying a concrete foundation. Because people normally build in this manner, the Halachah considers the concrete to be part of the ground. Nevertheless, the Maharsham sanctions building a mikvah out of concrete only when no other options exist. Rav Meir Arik (Teshuvot Imrei Yosher 1:99) adopts the same logic as the Maharsham’s retraction (although he notes that he lacked a copy of the Maharsham’s responsum), but he concludes that a concrete mikvah is absolutely acceptable, “without any reservations.” The Chavatzelet Hasharon (vol. 1 Y.D. 68) and the Satmar Rav (Teshuvot Divrei Yoel, Y.D. 77:7) also endorse the practice of building mikva’ot with concrete. For more on the Satmar Rav’s view, see Teshuvot Cheishev Ha’eifod (150:1).
Checking for Leaks
Rav Moshe Feinstein (Teshuvot Igrot Moshe, Y.D. 2:89) requires periodically inspecting a mikvah for zechilot. Rav Katz (Mikveh Mayim, vol. 3 p. 133) notes that poskim do not specify how often to check a mikvah for zechilot. He surmises that it depends on the age and condition of the structure, as an older structure probably needs more frequent inspections. Rav Katz notes that the process of checking for zechilot involves marking the water level of the mikvah, closing it for a day, and then inspecting the water level to see if it has fallen. Rav Yosef Singer told me that Rav Moshe Feinstein used to check the Lower East Side mikvah for zechilot annually on Tisha B’Av, when marital relations are prohibited, so as not to close the mikvah when people needed to immerse in it. Checking mikva’ot on Tisha B’Av is a widespread practice for this reason.21Rav Yirmiyah Katz has told me that the practice of checking mikva’ot for zechilot on Tisha B’Av exists worldwide, and Rav Ezra Frazer reports hearing similar comments from Rav Shlomo Levy.
In previous generations, mikva’ot were built with drains on the bottom. Despite the serious risks of the drains creating a zechilah or their plugs being subject to the laws of tum’ah (ritual impurity), they used to be the only practical way to remove water from the mikvah. However, with the advent of electric pumping machines in the twentieth century, it became accepted to construct mikva’ot without drains (see Teshuvot Divrei Yoel, Y.D. 76, and Teshuvot Mahari Shteif 71).
Rivers, Oceans, and Lakes
Until now, we have discussed zochalin within the context of leaks. Of course, the problem of zochalin clearly invalidates a flowing stream of rainwater, as the entire stream is one large zechilah. By contrast, we have already mentioned that one may immerse in a natural spring even if the water is flowing. From the time of the Talmud, authorities have debated whether to treat rivers as streams of rainwater or as springs. In reality, many rivers consist of a combination of rainwater and underground springs, so the debate revolves around how to judge such a mixture.22Indeed, Rav Yirmiyah Katz (personal communication) cautions that it is very difficult in practice to distinguish between rivers and springs. In addition to the ramifications for the laws of mikva’ot, Rav Elazar M. Teitz told me that this difficulty also arises regarding the laws of writing a get (Jewish divorce document; see Aruch Hashulchan, E.H. 128:33, and Pitchei Teshuvah, E.H. 128:30).
Rav (Shabbat 65b), determines each river’s status based on which type of water comprises a majority of the river at any given time. If it consists mostly of rainwater, then we treat the river as a mikvah and invalidate it as zochalin. If, however, underground springs provide most of its water, then it attains the status of a ma’ayan. One can measure the rain’s impact on a particular river by observing its size before the rainy season23Babylonia, where Rav and Shmuel lived, has distinct rainy and dry seasons during the year. The end of the dry season is the time when a river is considered most likely to be a ma’ayan since several months have just passed without any rain. and attributing any growth to rainfall. Accordingly, the same river might be a ma’ayan during a drought and lose this status after a downpour.
The Gemara cites one statement of Shmuel that appears to agree with Rav.24According to this version of his view, Shmuel says that the only river that purifies is the Euphrates, and only in the late summer (when it rarely rains in the Middle East). This statement implies that rainwater generally comprises most of a river’s water, invalidating it for immersion. Shmuel identifies the Euphrates as an exception because it contained so much spring water that late in the summer, after several months without rain, it contains more spring water than rainwater. On the other hand, Shmuel elsewhere adopts a contradictory view. This Gemara presents a somewhat enigmatic statement, “Nahara mikipei mivrach” (“A river grows from its rocks [in the riverbed]”). Tosafot (s.v. D’amar Shmuel) interpret this quotation as meaning that a river’s primary source of water is its underground springs. Tosafot explain, based on the Gemara (Ta’anit 25b), that for every unit of rain that falls, twice that amount of water percolates into the river from underground aquifers. Consequently, even if we observe that the river swells tremendously after rain has fallen, we may assume that the river still contains more fresh water than rainwater, because double the amount of rainfall emerges from the aquifers.25The Shach (Y.D. 201:14) presents this line of reasoning. Tosafot in Bechorot (55b s.v. Ein) cite an alternative rationale for this version of Shmuel from Rabbeinu Tam. They suggest that even if most of a river’s water comes from rain, it may yet be considered a ma’ayan. Rabbeinu Tam notes that at the moment that each raindrop hits the river, the spring water in the river vastly outnumbers this lone drop. Accordingly, the river nullifies it (bitul), thus giving that drop the status of spring water. This process repeats itself indefinitely (kama kama batil) as every drop falls. Hence, although the sum total of rainfall outnumbers the original spring water, the rainwater has been systematically converted into spring water before it can harm the river’s status as a ma’ayan. This latter interpretation of Shmuel’s view thus shows him as considering all rivers to be ma’ayanot. However, if a river or stream dries up completely when there is a drought, then the Rama (Y.D. 201:2) notes that it is clearly nothing more than a flow of rainwater (chardalit shel geshamim), which no authority would consider a ma’ayan (see Mikva’ot 5:6).
The Rishonim debate which opinion to follow. Most Rishonim accept Rav and the stricter version of Shmuel, which judge each river by the majority of its waters.26These Rishonim include the Rambam (Hilchot Mikva’ot 9:13), the Tur (beginning of Y.D. 201), the Ramban (in his commentary to Shabbat 65b), and the Rashba (Torat Habayit, Sha’ar Hamayim, Sha’ar 11). Tosafot (ibid.), however, cite Rabbeinu Tam as ruling in accordance with the lenient version of Shmuel. Tosafot conclude, “We rely upon this view to immerse in rivers, even if they are quite swollen [from rain].” Some Rishonim adopt a compromise view. They suggest that if a river swells after significant rainfall, then even Rav would permit immersing specifically in the part of the river that existed even before the rain, as this original section clearly came from natural springs and not from the rain.27See Ran (Nedarim 40b s.v. Umikol Makom) and Beit Yosef (Y.D. 201 s.v. Vekatav Od Haran). The Shach (Y.D. 201:11) claims that even Rabbeinu Tam, who permits tevilah in rivers, intends to allow it only in the section of the river that remains in the dry season.
The Shulchan Aruch (Y.D. 201:2) prohibits immersing in rivers under any circumstances. The Rama, though, records that communities located far from mikva’ot would immerse in rivers. The Rama concludes that it is preferable to follow the Shulchan Aruch’s opinion, but one should not admonish those who do immerse in rivers. Writing in the late nineteenth century, the Aruch Hashulchan (Y.D. 201:42) notes approvingly that women who lived at a great distance from a mikvah would immerse in rivers.
Today, with the advent of modern means of travel, poskim rarely, if ever, sanction immersion in rivers. Moreover, Rav Yirmiyah Katz (in 2001) told the National Council of Young Israel rabbis that he has made small mikva’ot for less than $20,000 in private individuals’ backyards and garages in places which are far from centers of Orthodox Jewish life. A Rav perhaps might sanction an Ashkenazic Jew relying on a river for tevilat keilim in case of great need, such as for baalei teshuvah visiting parents who live extremely far from a mikvah. Such a decision would depend on the specific circumstances and available alternatives in each case.
Finally, the Tannaim debate whether oceans are acceptable for immersion despite the fact that they are zochalin (Mikva’ot 5:4). Rabbi Yosei classifies oceans as ma’ayanot regarding exemption from concern for zochalin.28See Beit Yosef (Y.D. 201 s.v. Vechol Hayamim) regarding the status of oceans in other aspects of hilchot mikva’ot. The Shulchan Aruch (Y.D. 201:5) codifies his view.29Rav Yirmiyah Katz (personal communication) notes that many practical problems arise during the actual implementation of immersion in an ocean, so an eminent rabbi must be consulted before doing so. The Aruch Hashulchan (Y.D. 201:42) adds that lakes with still water are acceptable for immersion even if they dry up completely during a drought. Their water does not flow beyond their boundaries, so it does not present a problem of zochalin. In practice, though, a skilled Rav must thoroughly investigate a lake before it can be used for immersion, in order to verify that its water indeed does not flow beyond its boundaries.
Conclusion
Natural springs and oceans avoid many halachic pitfalls, but reality generally prevents us from immersing in them.30Rav Yirmiyah Katz (personal communication) notes that hot springs routinely employ man-made pipes to regulate their temperature. Such springs may not be used for tevilah. Thus, we routinely use mikva’ot, despite the risk that leaks will invalidate them. Modern technology has enabled us to minimize concern for leakage by constructing mikva’ot from concrete and by pumping water out of them from the top, rather than draining them from the bottom. Nevertheless, we must check mikva’ot from time to time (usually on Tisha B’Av) to ensure that leaks do not develop.