The Torah requires a mikvah to be used for specific cases of tumah.

I heard in a lecture that there is one opinion who thinks that it is good even halachikly, but I don't know the reason for that.

Is a modern day bathtub or jacuzzi a valid Mikva on a Biblical level?

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    Many opinions would think it is, but it should be noted that almost everyone would not use such a Mikvah, at least for rabbinic reasons.
    – Double AA
    Commented Nov 21, 2016 at 22:46
  • RI in Baba Bstra stated thst sheuvim is isur derabansn
    – kouty
    Commented Nov 21, 2016 at 23:10
  • @kouty Rambam too seemingly Mikvaot 4:2
    – Double AA
    Commented Nov 22, 2016 at 0:11
  • Comments are not for extended discussion; this conversation about how much water is needed and the volume of bathtubs has been moved to chat. Commented Nov 27, 2016 at 5:24
  • See here for a fascinating exploration of the subject, along with a case study of Mikvahs in America before WWII: dropbox.com/s/kjkbis74goflkmw/…
    – Chaim
    Commented Aug 20, 2017 at 13:11

5 Answers 5


Following Rabenu Yitschak in Tosfot BB 66b (also reported in Tur YD 201), Rambam Yes, Following Rashi, Rashbam, Rabenu Tam, RaShBA baal Hatosfot, Rabenu Shimshon and Rosh, no. The Tur Siman 201 refered to two opinions and stated that the problem for Kulo Shauv is deorayta. Bet Yosef in the same siman reported that Rambam, Ramban, Rashba and Ran agree with RY. According to the Raavad there are several kinds of Shauv but the OP is for a Bathtub which is filled normally. The Shulchan Aruch 196, 3 (the Shach said this in his name by dyuk) ruled as Rambam, this psul is derabanan, the RMA (196, 3) stated as Rashbam and Rabenu Tam, this is deorayta.

A second problem is that the bathtub is already a keli before that they cemented it over the ground. But a bathtub is a keli which is made only to be cemented over the ground.

The size of the Mikve is greater than the size of a standard bathtub but there is big bathtub.

It is not sure at all that biblically a bathtub is a good mikve.

In conclusion, from the Shauv point of view Machloket Rishonim and Machloket Acharonim.

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    Note as well that it's not entirely obvious that modern tap water is Sheuvim at all, plus the fact that it might be considered Nimshakh over the pipes which are kavua in the ground.
    – Double AA
    Commented Nov 22, 2016 at 22:37
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    @DoubleAA tsinor is not חקקו ואחר כך קבעו + כלי מתכת + כלי קיבול?
    – kouty
    Commented Nov 23, 2016 at 1:49
  • @DoubleAA I will learn the pipes again. I not am not sure that nimshach falls directly in mikve. + Koach GAVRA . I will verify. Thanks
    – kouty
    Commented Nov 23, 2016 at 2:08
  • @DoubleAA for hamshacha if the water falls directly in the mikve, is it hamshacha? For Tsinor. When You close the tap and open, this is not sheiva bekoach Gavra?
    – kouty
    Commented Nov 23, 2016 at 3:30
  • I'm not saying anything definitive, but if you want to find a way to make a bathtub only Pasul Miderabanan, this is another way to go. Opening the tap is just Hasarat Moneia' for instance.
    – Double AA
    Commented Nov 23, 2016 at 3:32

According to the Rambam Rif Ramban and Ran Only a pool which is dug into the ground will be good to dip into on a biblical level even in drawn water, but miderabanan requires rain water. In contrast Rabeinu tam and others say that more than half the water has to come from rain on a Biblical level see Tur, Beis Yosef Yore Dea 201 .

A BATH IS POSUL MIN HATORAH (unfit) however big it may be, as the tub is a kli prefabricated vessel and gemoro in bovo kama 67a says clearly:

תניא צינור שחקקו ולבסוף קבעו פוסל את המקוה

A pipe that was carved then fixed on the ground renders a mikva unfit. Tosfos explains that this is only when it has 4 walls under the pipe so it is a container - כשיש לו לבזבז מד' רוחותיו (and that is what a bath tub is.)

Indeed the Ramban Bava Bastra 66b clearly states it would be forbidden Biblically to Tovel in a kli (like a bath tub). Even though one could Tovel in a pit attached to the ground filled with drawn water mideoraisa (biblically), the latter is forbidden rabinically just in case one Tovels with a Kli

אי שאובה כולה דרבנן אמאי פסלי למקוה הניחא אי שאובה דאורייתא שלשה לוגין גזרו בה רבנן אלא אי אמרת דרבנן אמאי גזרו בהו כלל למפסל מקום איכא למימר הואיל ומקוה הוא שרובו של אדם עולה בהן כשנפלו במקוה גזרו בהן משום דאתי למטבל בכלי

See Tosfos האי מסוכרייתא דנזייתא on Kesubos 6a which states a bath that is plugged is considered a kli (vessel):

מסוכרייא דנזייתא סתימת גיגית של שכר אסור להדוקה דשמא תבטל הסתימה אצל הגיגית ויעשה כלי
By blocking a hole in a container with a plug you render the container into a vessel (and this is prohibited on shabbos)

Those who live in Africa and other third world areas might have clay baths attached to the ground may be considered good mikva bibically speaking so long as it contains more than 40 Seah (5760 fluid eggs) .

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    That's not what a bathtub is. A bathtub isn't even a kli kibbul at all. It has a giant hole in the bottom. See Rambam Mikvaot 6:4
    – Double AA
    Commented Aug 20, 2017 at 3:38
  • The kesef mishna there says דנוקב נקב המטהרו דהיינו במוציא זית it needs to fit an olive through the hole in our case thats the metal drain which usually has much smaller holes than that.
    – user15464
    Commented Aug 20, 2017 at 3:57
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    Every bathtub I've ever seen could handle an olive. Maybe it often has a grate filter sitting over the hole so nothing valuable get washed away accidentally. But that's separate from the actual tub. The tub itself is holey.
    – Double AA
    Commented Aug 20, 2017 at 4:06
  • where i live there is a thick metal flower like lattice which is part of the bath that stops thing from blocking the plumbing you can add something extra to stop the hairs from going down the drain
    – user15464
    Commented Aug 20, 2017 at 4:23
  • Doubleaa My edit has rendered your comment irrelevant as i explained from Tosfos by plugging a bath you make it into a kli
    – user15464
    Commented Mar 24, 2020 at 11:58

It is possible (but as @user6591 said, it needs to be a big tub like 76.1 gallons of water), but the only practical difference it will make is that the children that come from relations after such a dip are ok to marry, (if they do not have bad character traits)

P.S. It is possible to make a completely kosher mikvah in a bath tub, but there are some details, see From what materials can a mikveh be made? for a start

  • My mother used a bathtub as a mikva before getting married (it was organized and supervised by a rabbinical authority though).
    – ezra
    Commented Nov 22, 2016 at 2:26
  • Are their character traits proving whether this is a good mikva? Are you claiming it is not a good mikva but if their traits are good, one may marry them? Or that it is a good mikvah, but you still may only marry them after they pass the character trait test? This is confusing.
    – user6591
    Commented Nov 22, 2016 at 4:42
  • @EzraHoerster wow, this sounds interesting, can you give me more details regarding that bath tub
    – hazoriz
    Commented Nov 22, 2016 at 10:29
  • @user6591 The state of the parents during conception affects the children, one of the negative affects is if the mother was a biblical (if I am not mistaken) nida, but if she was coincidentally in a pool or Beach or maybe even a bathtub before conception there is no bad effect on the child's character and it is permitted to marry them, practically my understanding is that the Rabbis say that if the child's traits are good you can marry them and not be worried that maybe the mother was a nidda at the time of conception
    – hazoriz
    Commented Nov 22, 2016 at 10:36
  • so then what you meant to say was practically speaking it won't make a difference since if the children have good character traits you can marry them. This is therefore an inconsequential point.
    – user6591
    Commented Nov 22, 2016 at 10:46

i don't think the notion of חקקו ולבסוף קבעו is relevant as that is because שנקרא שם כלי בתלוש but a bathtub is unusable before installed to the ground. As far as the water could ice cubes be melted in the bathtub? i think most rishonim hold פנים חדשות באו לכאן שמג ןא the פסול שאובים

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    Welcome to MY! Would you mind please editing your post to explain what these terms mean? Also please take a look at our tour when you get a chance, as MY might be different from other sites you’re used to. Hope you’re staying well during the current outbreak, and looking forward to learning with you.
    – DonielF
    Commented Mar 22, 2020 at 0:57
  • חקקו ולבסוף קבעו is from the sugya בבא בתרא סו:א : דף של נחתומין שקבעו בכותל - ר"א מטהר, וחכמים מטמאין; מני? אי רבי אליעזר, אפי' חקקו ולבסוף קבעו! אי רבנן, אפילו קבעו ולבסוף חקקו נמי! לעולם רבי אליעזר היא, ושאני פשוטי כלי עץ, דטומאה דרבנן. מכלל דשאיבה דאורייתא, Commented Mar 24, 2020 at 14:30
  • I'm familiar with the terms you use, but not all the users on the site are. I'm by no means an expert on Hilchos Mikva'os – how do you think a random user who's barely heard of a Mikvah will read this?
    – DonielF
    Commented Mar 24, 2020 at 15:02
  • Also, you can edit your post to clarify any points; you don't need to post a new answer entirely as I see you've done.
    – DonielF
    Commented Mar 24, 2020 at 15:03
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    R Dani welcome! Our site is different from others you may have encountered (read one "new user guide" here.) Remember most people here don't know you to know you have published a serious Sefer about Taharot, so they have no reason to believe you without explicit citations to back up your claims. To me it's frankly an honor that you're here. But that notwithstanding, you will succeed at sharing the most Torah here if you learn and stick to the site format. eg. to keep things running smoothly, answer boxes are used only for answering the question at the top of the page.
    – Double AA
    Commented Mar 24, 2020 at 19:00

I don't believe the precedent of חקקו ולבסוף קבעו is relevant as is clearly stated that is because יש שם כלי בתלוש. Since a bathtub is unusable בתלוש even though it has a form of a בית קיבול it is not considered a כלי קיבול and is kosher for a mikvah.

  • Please give your sources. Commented Mar 23, 2020 at 13:44

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