I have been reluctant to ask this question on this website because it sounds so ridiculous, but as Hillel said in Avot 2:6 "one who is bashful cannot learn" so here goes...

Why is it permissible to flush a toilet on Shabbat?

This question asks it from the point of view of water pressure and causing pumps to turn on, but I do not see why it is not moving material (human waste) from rishut hayachid (a private domain) to either rishut harabim (public space) or karmelit (river or similar place where public does not go) (definitions of terminology here).

I read this idea years ago on a humorous "How to mess with Baal Teshuvas" list, but it stuck in my head because I really did not have an answer for such an thing. I am sure there is solid halachic reasoning on why it is perfectly permissible, but I am just not learned enough to know what it is. Please clue me in!

  • I asked myself the same question some time ago, and the only kulah I found was that this is melacha she'eina tzicha legufa (the result of the work is not required), because you want the water (and etc.) not to be in your house and not that you need it to be outside.
    – jutky
    Commented Oct 18, 2014 at 21:15

3 Answers 3


Tosfos Eruvin (86b) and Mishne Berurah (355:6) explain that since the waste initially travels into an extension of the private domain, it is permitted. Even though the waste might later travel into a larger body of water which would have the status of a karmelis, that is not your primary intention, and therefore it is allowed.


Firstly, as Clint Eastwood already touched upon, it is not at all clear that the waste one flushes will go to either a reshus harabbim (public domain) or a karmalis, at least without requiring others to act further down the treatment process:


from http://www.thewatertreatments.com/wastewater-sewage-treatment/design-sewage-water-waste-water-treatment-system/

Even if the particular circumstance where such that the waste was brought to a reshus harabbim, "From the Torah one is not liable except when an object is lifted in a reshus hayachid (private domain) and set down in a reshus harabbim (public domain) or the reverse..." (O.C. 347:1) so at the very most we a dealing with an Issur d'Rabbanan (Rabbinic Prohibition). Dealing with a Rabbinic prohibition, if any, the case falls fairly well under the exemption provided to preserve Human dignity (כבוד הבריות, see O.C. 312:1 for a parallel concern with earlier hygiene issues).


Flushing a toilet is definitely not carrying because the network of sewage pipes under the city is a reshut hayachid. As to the outlet pipe, there is some delay and disconnect between the flush of your toilet and waste coming out the other end. You will contribute to the flow, but the stuff you flush only pushes out the stuff that flows out, so this action is a grama.

I would say that unless you have your own personal sewer, your flushings will become batul in the rest of the city's flushings and by the time it leaves the sewer, it will no longer be your halachic problem.

  • 2
    Clint eastwood is jewish? What about john malkovich? Anyway, I used to live in rural farms all around and we had our own gravity driven private sewers. Does that mean I should have avoided flushing the toilet if my private sewer had a pump? Commented Oct 15, 2014 at 15:43
  • So what's the Halacha if you have your own septic tank? In my neighborhood at least, every 3 - 5 years, residents would call a plumbing company to come drain their own septic tank.
    – Moshe
    Commented Apr 9, 2021 at 19:51

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