In our last chapter, we explained hamshachah and hashakah, two processes that permit filling a mikvah with mayim she’uvim, such as tap water, which would otherwise be unsuitable for immersion. This chapter discusses a third option to render mayim she’uvim suitable for immersion, the procedure commonly referred to as zeri’ah.
The Process of Zeri’ah
The Mishnah (Mikva’ot 6:8) describes a situation in which two pits exist along a mountainside, one above the other. The upper pit contains the required volume of rainwater for a mikvah (forty sa’ah; see previous chapters) while the lower pit is empty. In order to fill the bottom pit without waiting for rainfall, the Mishnah advises pouring buckets of water into the upper mikvah so that the resulting overflow will fill the bottom pit. Recall from the last chapter that once a mikvah contains the requisite amount of rainwater, one may add an unlimited amount of mayim she’uvim to the mikvah and it remains valid. Moreover, the added water is halachically transformed from mayim she’uvim into valid mikvah water. Thus, the buckets of water become fit for immersion the moment they touch the upper mikvah; the water then flows into the lower pit, resulting in two valid mikva’ot.
Most contemporary mikva’ot employ this process, called zeri’ah, by building a pool to hold rainwater (bor zeri’ah) next to a pool (bor tevilah) that will be filled with water that will overflow from the bor zeri’ah. After forty sa’ah of rainwater enter the first pool, we open the faucet above it, causing it to overflow into the adjacent pool (see diagram for clarification) through a hole in their common wall. The bor zeri’ah, which already constitutes a valid mikvah, converts the mayim she’uvim into valid mikvah water. When the water in the bor tevilah needs to be changed for health or aesthetic reasons, we empty it and repeat the process of zeri’ah. This term literally means “planting.” Conceptually, the water is replanted into a body of natural water, thus removing its status as mayim she’uvim (see Teshuvot B’tzeil Hachochmah 3:127), just as a seed achieves a new status when it is planted in the ground.
Zeri’ah vs. Hashakah
The process of zeri’ah differs from hashakah (see last chapter) because hashakah validates water, which entered the bor tevilah unfit for immersion, by subsequently connecting it to an adjacent pool of valid rainwater (bor hashakah). By contrast, zeri’ah validates the water before it enters the pool.
The Chatam Sofer (Y.D. 203; cited in Pitchei Teshuvah, Yoreh Deah 201:24) and the Chazon Ish (Y.D. 123:1-5) vigorously support the use of zeri’ah to create mikva’ot. In fact, mikva’ot in pre-war Hungary normally used the process of zeri’ah alone to render the water fit for immersion. Similarly, mikva’ot built in Bnei Brak and elsewhere in Israel under the supervision of the Chazon Ish operate with zeri’ah alone, without hashakah.1These mikva’ot do, however, use hamshachah. Interestingly, this phenomenon might have ancient roots. In an essay published in Techumin (17:389-398), Asher Grossberg argues, based on archeological findings, that the ancient mikvah at Massada was filled solely through zeri’ah.2Also see Techumin (19:448-455), where Asher Grossberg argues that ancient mikva’ot found in Jerusalem used either zeri’ah or hashakah. For a general discussion of the acceptability of archaeological evidence in halachic discourse, see Rav Yonatan Adler’s essay in Techumin (24:495-504).
Problems with Zeri’ah
Three problems can arise if a mikvah is created exclusively through zeri’ah. The primary concern stems from the fact that the water already enters the bor tevilah as valid mikvah water, rather than undergoing a process inside the bor tevilah. As we discussed last chapter, three logim (a bit less than a quart) of mayim she’uvim disqualify a mikvah that lacks forty sa’ah of valid water. Accordingly, if the bor tevilah contains three logim of mayim she’uvim when zeri’ah is performed, then these three logim will invalidate the new flow of water as it arrives from the bor zeri’ah. Rav Katz (Mikveh Mayim, vol. 1, pp. 43, 59-60) relates incidents where more than three logim of mayim she’uvim were unintentionally present in the mikvah before the zeri’ah procedure and people subsequently immersed in the mikvah without realizing that it was not fit for immersion.
Today, when we generally employ pumps to drain the mikvah, this problem routinely arises. The pump can never remove every last drop of water from the mikvah, as some backwash of water always enters the pump, then leaves the pump and returns to the mikvah. In this situation, some mayim she’uvim will remain in the mikvah because the receptacles in the pumps will render the water mayim she’uvim before it returns to the mikvah (see Teshuvot Minchat Yitzchak 5:90 and Teshuvot Chelkat Yaakov 3:54). Hence, the mikvah must be dried thoroughly by hand to ensure that three logim of mayim she’uvim do not remain.
Due (in part) to this problem, most contemporary mikva’ot employ both zeri’ah and hashakah. If either process fails, then the other serves as a back up. Rav Avraham Chaim Na’eh (Shiur Mikvah, p. 165) notes that the accepted practice in Jerusalem is to employ both zeri’ah and hashakah. Rav Moshe Feinstein (Teshuvot Igrot Moshe, Y.D. 1:111) similarly recommends using both hashakah and zeri’ah whenever possible without great financial difficulty. Moreover, most mikva’ot also use hamshachah (as described in our previous chapter), in addition to the zeri’ah and hashakah processes, to further insure their validity. This combination recalls the words of Kohelet, “Two is better than one… and a threefold cord is not quickly broken” (4:9-12).
Zeri’ah B’Zochalin
The Acharonim raise a second challenge to zeri’ah, which relates to the problem of zochalin. Recall from two chapters ago that a mikvah is invalid if its waters flow beyond its boundaries (into a hole, crack, etc.). Accordingly, a number of Acharonim question how zeri’ah can work if the water flows out of the bor zeri’ah during the process.3Chazon Ish, Y.D. 123:1; Teshuvot Maharam Schick, Y.D. 198; and Teshuvot Maharsham 1:122,145. If a mikvah is disqualified when its water flows out, then the bor zeri’ah should lose its status as a valid mikvah while it overflows into the bor tevilah. Without this status, it should not render the tap water fit for immersion.
There are several ways to address this problem, and different mikva’ot have adopted various approaches. The Chazon Ish (ibid.) notes that the problem is less severe in mikva’ot where the tap water is validated by hamshachah even before it enters the bor zeri’ah. As we discussed last chapter, most Rishonim believe that even a full mikvah of mayim she’uvim which have undergone hamshachah is acceptable on a Torah level and invalidated only by rabbinic legislation. Thus, use of hamshachah reduces the entire issue to a rabbinic level and consequently allows greater room for leniency.
In order to completely resolve the problem of zochalin, the Chazon Ish suggests an approach that many mikva’ot today employ. He proposes constructing (see diagram at the conclusion of this chapter) the bor zeri’ah so that tap water enters through a hole in the wall’s lower portion and the overflow exits into the bor tevilah through a hole in the upper part of the wall that is shared by the bor zeri’ah and the bor tevilah.4For a discussion of a variation on the Chazon Ish’s solution employed by some mikva’ot, see Mikveh Mayim 2:64. According to the Chazon Ish, this method alleviates concern for zochalin because the tap water enters the lower part of the bor zeri’ah, which is completely stationary. Rav Yaakov Breisch (Teshuvot Chelkat Yaakov 3:53:2) writes that he employed this method when constructing the mikvah in Zurich in 1959,5The bor hashakah in Rav Breisch’s mikvah actually held enough for two mikva’ot, as we will explain in the following chapter. and Dayan Yitzchak Weisz (Teshuvot Minchat Yitzchak 2:23) recounts using it for the mikvah in Manchester in 1957. Others criticize this approach, questioning how part of the mikvah can be considered stationary at the same time that another part constitutes zochalin.6See Mikveh Mayim (1:27-34) for a review of this issue.
Rav Yaakov Landa (in a letter printed in Taharat Hamayim, p. 183) suggests a third approach to solving concern for zochalin during zeri’ah. He recommends closing the hole between the bor zeri’ah and the bor tevilah while performing zeri’ah. In this manner, all the water remains in the bor zeri’ah, without any flow that raises concern about zochalin. After completing zeri’ah, the hole is then reopened and the excess water from the bor zeri’ah flows into the bor tevilah. Aside from practical concerns, such as the need for a bor zeri’ah that can hold an enormous volume of water, some criticize this method from a halachic perspective. They express concern that the water ultimately enters the bor tevilah through tefisat ye’dei adam (human intervention) when a human opens the hole leading from the bor zeri’ah to the bor tevilah.7For a summary of the rich literature regarding tefisat ye’dei adam in this context, see Mikveh Mayim (ibid.).
Some Acharonim deny the need for any of the aforementioned solutions. They believe that the issue of zochalin does not actually present a problem for zeri’ah.8Teshuvot Imrei Yosher (1:94 and 2:73), Teshuvot Chelkat Yo’av (Y.D.1:32), and Teshuvot Igrot Moshe (Y.D. 1:112). See, however, Teshuvot Maharam Schick (Y.D. 198). Rav Moshe Feinstein (Teshuvot Igrot Moshe, Y.D. 1:112) explains that a zechilah does not disqualify a mikvah per se; rather, the concept of zochalin means that an individual may not immerse even in a valid mikvah so long as its waters are flowing out. Accordingly, the bor zeri’ah retains its status as a valid mikvah throughout the zeri’ah process, so it renders the tap water fit for immersion and enables the creation of a second valid mikvah in the adjacent bor tevilah. Rav Moshe cites the aforementioned Mishnah in Mikva’ot as support for his approach, because zochalin do not arouse concern regarding the validity of the upper pit when water overflows from it into the lower pit.
Natan Sa’ah V’Natal Sa’ah
The process of zeri’ah also raises concern for an issue known as natan sa’ah v’natal sa’ah. The Mishnah (Mikva’ot 7:2) writes that if a mikvah contains exactly forty sa’ah and one adds a sa’ah of fruit juice (without changing the water’s color) and subsequently removes a sa’ah of rainwater (natan sa’ah v’natal sa’ah), the mikvah remains valid. Although the mikvah no longer contains the minimum forty sa’ah of water, it still has forty sa’ah of liquid and the water nullifies the independent character of the one sa’ah of juice. The Gemara (Yevamot 82b) limits this leniency to a situation where more than twenty sa’ah of rainwater (a majority of its contents) remain in the mikvah. If, however, one repeated the process of adding fruit juice and then removing water until half or more of the mikvah’s contents were fruit juice, the mikvah would no longer be valid.
Most Rishonim believe that only fruit juice presents a problem when it becomes half or more of the mikvah because a mikvah must be comprised of water. On the other hand, adding mayim she’uvim and then removing the original water does not create a problem, because the original forty sa’ah remove the she’uvim status from new water upon its arrival in the mikvah. Thus, when water is later removed from the mikvah, we do not distinguish between the original water and the she’uvim since all the water is now valid. Unlike a situation where the mikvah is transformed from a mikvah of water to one of fruit juice, here the mikvah remains a mikvah of water throughout.9Rashi (Yevamot 82b s.v. Natan), Ramban (Yevamot 82b s.v. Ha Ditnan), Rashba (Yevamot 82b s.v. Ha Ditnan), Ritva (Yevamot 82b s.v. Natan), Rosh (commentary to Mikva’ot 7:2), and Rabbeinu Shimshon (commentary to Mikva’ot 7:2).
However, the Rambam (Hilchot Mikva’ot 4:7) and the Ra’avad (Ba’alei Hanefesh, Sha’ar Hamayim) rule that natan sa’ah v’natal sa’ah even invalidates a mikvah when mayim she’uvim become half or more of its contents.10For an analysis of the Rambam and Ra’avad, see Chazon Ish, Y.D. 123:1-3. For further analysis of the Ra’avad’s position, see Teshuvot Beit Yitzchak, Y.D. 2:27. According to the Rambam and Ra’avad, it appears that more than twenty sa’ah of the original rainwater must remain in the mikvah in order for it to validate mayim she’uvim.
The Shulchan Aruch (Y.D. 201:24) and most of its commentaries rule in accordance with the lenient opinion advocated by the majority of Rishonim. The Shach (201:63), though, cites that the Tashbetz concludes that we should accommodate the strict opinion of the Rambam and Ra’avad, too. This poses a serious problem for the process of zeri’ah, as the repeated implementation of zeri’ah eventually removes at least half of the original forty sa’ah of rainwater from the bor zeri’ah. In order to avoid this problem, most contemporary mikva’ot employ both zeri’ah and hashakah (see, for example, Rav Moshe Feinstein Teshuvot Igrot Moshe, Y.D.1:111). This custom assumes that hashakah satisfies even the opinion of the Rambam and Ra’avad. The Chazon Ish, however, argues vehemently that the original forty sa’ah of rainwater does not remain even in a bor hashakah. Although it takes longer than a bor zeri’ah to lose the original rainwater, the Chazon Ish believes that the waters in the bor tevilah and the adjacent pool for hashakah easily mix and soon the original rainwater in the bor hashakah is lost. Hence, the Chazon Ish felt that there is no benefit to employ both hashakah and zeri’ah; rather, zeri’ah and hamshachah suffice in his view.11In Y.D. 123:3, the Chazon Ish questions whether the Ra’avad would necessarily invalidate all forms of zeri’ah.
Conclusion
Most mikva’ot employ zeri’ah, hashakah, and hamshachah to insure the their validity. The Chatam Sofer and Chazon Ish, though, felt that zeri’ah without hashakah suffices. An oral tradition explaining why the Chazon Ish strongly opposed using hashakah appears in Rav Katz’s Mikveh Mayim (vol. 1 p. 43). Again, we thank Rav Katz for graciously permitting us to reprint illustrations from his book to help clarify the concepts that we have discussed.