This letter was addressed to R. Yaakov Landau, the Rav of Bnei Brak and a leading Lubavitch Rabbinic authority.1

B”H, 21 Kislev, 5710

Greetings and blessings,

I am very grateful for your letter of 15 Cheshvan containing the directives you received from the Rebbe [Rashab] regarding [the construction of] a mikveh.2 As soon as I received them, I sent a copy of that portion of your letter to the inquirer, mentioning of course, your name. Enclosed is a copy of that letter.3

Some points that require explanation immediately come to mind [when considering the matter]:

a) When two mikvaos4are made side be side,5 it is always possible to check whether the [required] measure of rainwater in the mikveh has been reduced (whether because a small, unnoticeable amount is absorbed in the floor [of the mikveh] each day, because part of the mikveh became filled with dust, or the like). If, however, the two mikvaos are one on top of the other, and one is frequently adding hot or cold water in the upper pool anyways,6 it is possible that an amount of time will pass before it becomes noticed that the measure of [rain] water has decreased [in the lower pool].

b) With regard to subsec. 4:7 that the water from the lower mikveh should rise above the floor of the upper pool when it is being filled with rainwater. Perhaps it can be explained that the rationale is that [in this way] three lugim of water coming from the municipal water works8 would never collect in a low place in the upper pool above the level of the connection to the lower pool.9 Nevertheless, when one desires to clean the upper pool without [emptying] the lower reservoir, what should be done?10

c) With regard to subsec. 6:7 That one should immerse oneself while the body is extended [horizontally to its full length]. On the surface this is difficult [to understand]. Since the water is high, [to extend one’s body to its full length,] it will be necessary to hold on to something. Note the Alter Rebbe’s Tikkun HaMikveh11 which speaks of holding with one’s hand. As a result [of holding on to something,] there will be creases in one’s hand and thus the stringency leads to leniency.

d) In subsec. 9:7 after the words “in the earth of the courtyard,” [the word] bekavannah [was included]. I did not understand the intent of that term.12

e) In subsec. 14:7 [it states that] the measure of the mikveh should be 726 liters [somewhat less than 192 gallons]. This is somewhat perplexing. After all the stringencies mentioned above, [why] was there no desire to fulfill the requirements of those who require a larger measure of water in the mikveh,13757½ liters or even 762 liters ([see Tal Talpios, 5666, sec. 8, quoted in Rav Feldman’s edition of the Kitzur Shulchan Aruch; one should also look in Darchei Teshuvah 19:27, but it is not presently accessible to me)?

Thanking you in advance for your explanations and insights14ארותיו) with regard to all the above.

You have undoubtedly already received the index [to the Rebbe Rashab’s maamarim]. I would be grateful if you would notify me if you have anything to comment or add [concerning it].

I conclude with wishes for all forms of everlasting good and greetings to the members of your household.

M. Schneerson

I was just able to obtain the Darchei Teshuvah mentioned above. According to his interpretation of [the statements of] Chasam Sofer, 779 liters are required. The texts Shiurei Mikveh, Arugas HaBosem, and Netivim BeMei HaYam, Vol. 3,sec. 23, which was just printed in Eretz Yisrael, contain analytical discussion of this issue.