With Covid and the health concerns about going to a mikvah. I was wondering if it's feasible to convert our pool into a fully kosher mikvah (for the wife to use). Given that tzniyus concerns are taken care of the Q is purely in regards to the mikvah. The pool is an inground pool with a side hot tub which is connected by a wall and hole between it and the main pool.
If that hole were adequately plugged, and the hot tub filled with only rain water, and disconnected from the filtered water flow.
What would be needed?
Of course I'm going to ask my LOR, but I wanted to find out the feasilbility beforehand, and find out the Q's so that I can have all my facts/measurements on hand.


  • 5
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    – AKA
    Commented Apr 26, 2020 at 20:36
  • see Shabbos 65: Commented May 7, 2020 at 5:41
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    – mbloch
    Commented Jun 3, 2020 at 5:23

3 Answers 3


Obviously, as you mentioned, you'll ask a specific shaila. Here's a couple of issues for you to check out and ask:

1) how was your pool made? If it was a preformed concrete block which is placed in the ground, it might have "toras kli" on it (halachically called a vessel) which would make it pasul. You might need to undo the status of a kli by detaching it from the ground, puncturing a hole in the bottom so it wouldn't be able to hold water, and then reattach it. This would be a real pain to do with a hot tub!

However, most (though not all) in-ground pools and tubs are made from just pouring cement into the hole and attaching tiles. In this case, it's unlikely that anything had "toras kli" before attaching it to the ground. (Shut Shevet Halevi and Minchas Yitzchak are both lenient regarding tiles, even if they have an indentation in the back to receive the cement, since they are meant to be attached to the ground.)

2) Is there a drain of any sort? You only mentioned a hole between the tub and the pool. Is there a drain in the tub itself? depending on how it is constructed and where it's located, that could also be a problem.

3) How would you plug up the hole? You don't want a plug which can be mekabel tum'ah. Plastic or rubber is usually ok, metal ones aren't. Some plugs also have indentations which could be problematic (a 'beis kibul' or a receptacle is called a kli) so you would need to check out how the hole is being plugged up.

4) How much water does the tub hold? The minhag is to have 1000liters (shu't cheshev HaEfod and many sefarim quoting him) though the actual shiur is between 750-850 liters. You need to check with your rav about it. There needs to be enough space above this level of water that even when a person goes in, and the water rises, it won't spill out of the mikva.

(There's a preference that there should be a shiur of water below the hole connecting the pool and tub, such that even if the hole gets left open accidentally, there's more room to rely on the shiur beneath the whole see siman 201 sif 40-41.)

5) How is the water entering the tub? we generally want the water to enter after running on the ground at least 3 tefachim to accomplish "hamshacha" which removes lots of issues with the water. You want to make sure the area surrounding the tub is free of anything which could make the water pasul (i.e. it shouldn't hit any tools, or anything which has toras kli on it.)

6) You need to make sure the pool is entirely dry before any rain water goes in. That means after draining the water, you would go over it with towels and maybe putting heaters there to ensure it's dry. There's often a problem when concrete gets dried, but then afterwards "sweats" the water from inside it. So you need to check with your LOR how dry you have to make it.

  • thanks great info: (1) poured cement (2) drain in the pool (I have to check hot tub) (3) woudl have to get plastic plug (4) the tub is approx 60 cu ft (which I think holds apprx 1,700 liters). I have to check the hole location. It also has the ledge slightly lower than the water level so it could be filled to the top and water "touch" the pool via the top. with all 1,700 liters below that point (5,6 I didn't think into this - something woudl have to be setup to accommodate
    – Chaim
    Commented Apr 27, 2020 at 18:14

I spoke with my LOR who was nice enough to entertain the idea. His response was:

In theory

it's possible using the inground neighboring hot tub as the בור (pit) to store the 40 seah of good water, and allow השקה (through the hold of adequate size) for the waters to touch. There would be work involved to insure the details. For example: that things were totally dry to start and no leaks and that it's close enough to the roof of the house to get enough quantity of runoff rainwater and that as the rain waters are diverted into the בור that they don't get disqualified along the way. i.e. doable, but not simple.

He also pointed out that a while back - when Jews came to America and the idea of mikvah was frowned upon (dirty) and many people stopped going - that someone published a book detailing how people can make their own mikvah (to their own standards of cleanliness).

In Practice:

Given that all of the requirements were met, and with his backing, he would be able to find someone qualified to inspect and give the initial OK that it's kosher to use for a niddah. However, in order to maintain the "hechsher" the Rav hamakshir would have to keep on top of it so that he's satisfied to maintain the hechser for subsequent tevilahs. Even if I learned what needed to be done (so that I'm satisfied). He felt no one would be willing to take responsiblity for it going forward (i.e. past that initial state).

Where does this leave me / what can we do? On the positive side, at least for my local mikvah, I've heard that they are EXTREMELY concerned about covid and that there is absolutely no reason for any contact (other than immersing in the water) as all preparations are to be done beforehand, you bring your own towel/robe, etc. No one checking finger nails, etc. You do everything on your own, and immerse. So thus it woudl seem that the only "risk" is the water, whcih is highly chlorinated. (Hope this helps)

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    The "someone" your LOR mentioned (second paragraph of "In theory") is R' David Miller z"l of Oakland. The sefer is called Mikveh Yisroel, and it's available online at beta.hebrewbooks.org/reader/reader.aspx?sfid=41215. (Also see judaism.stackexchange.com/a/8432/18471.)
    – Meir
    Commented May 6, 2020 at 20:37
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    It's a fascinating book, controversial but backed by reliable authorities. But the reality has changed and so the book isn't practical anymore. Rav Miller was basing himself off the assumption that water from the tap was kosher m'ikar hadin for a mikva- it came from the ocean/reservoir etc. and none of the pipes were halachically called keilim. However nowadays with filters, water meters, tanks and more, poskim assume the water did pass through keilim and became pasul for a mikve unless you know otherwise. So the sefer is interesting in idea, but not practical anymore.
    – Binyomin
    Commented May 6, 2020 at 21:10
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    @Binyamin that's not true. Water from the tap is probably still kosher meikar hadin. Common practice is to be more machmir now because we can afford to, but the reality isn't very different
    – Double AA
    Commented May 6, 2020 at 22:12

The short answer is, yes, it is possible that you could make the conversion but some minor construction might be necessary.

The details are more complicated than you are presenting in your question and you definitely would need to consult with a competent Orthodox Rav with expertise in Mikvah construction to see what you have specifically.

This link to a Chabad site discussing Mikvah construction will at least familiarize yourself with more details related to your question.

Mikvah Construction


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