I've recently replaced the trim in my bathtub/shower, including the drain trim. The neighbor below me (I'm in a condo) has said my bathtub seems to leak onto his ceiling now. Since I suspect there's hardly a way to cause a leak by just replacing the shower valve trim (correct me if I'm wrong), I'm curious if I installed the drain trim incorrectly.

Following online tutorials, I removed the old one and cleaned the area up, then put plumbers putty in a ring around the top of the threads of the new one, and screwed it in as tight as I could.

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The darker colored putty on the bottom threads is likely from the old drain. Did I not put enough putty on all the threads? Or is that old putty causing an issue? Could it be the O ring in the actual drain?

  • Screwing it in as tight "as you could" can be a problem with rubber gasket seals. There's not tight enough and not sealing, and too tight causing the seal to displace (squeeze out) and not seal. As noted in answers, re-using the (presumed to exist) old rubber washer under the tub rather than replacing it with a new one isn't improving your odds of a leak-free seal, and most "modern" plastic tubs do specify using 100% silicone sealant on that seal ring as well, and instead of plumber's putty on the top side. It's a difficult job to do right without access to the underside of the tub.
    – Ecnerwal
    Aug 27, 2020 at 23:49
  • If using putty, it should be between the ring of the drain and the face of the tub, not "around the top of the threads" - you should have squeeze-out to clean up all the way around after screwing that in. But that (by itself) won't solve a leak from the underside where the "drain shoe" seals to the bottom of the tub.
    – Ecnerwal
    Aug 27, 2020 at 23:52

3 Answers 3


I can't really tell from the picture, but the gasket looks kind of stretched out and I'd guess your leak is coming from it not sealing completely, not being located exactly right, or (perhaps because of the old putty?) the flange piece is not drawing down as tightly as it should to compress the gasket properly.

The gasket should be somewhat soft, elastic, and flexible in order to work right and ensure a good seal. Once you take the old flange piece off, if the gasket that has lost its flexibility (and they do over time) it just can't seal properly again.

You should remove all the old putty from the threads and fittings and clean it up as well as you possibly can. The old putty isn't really doing any good anymore and may be causing some kind of gaps or other interference that ends up leaking. A small wire brush might be useful to get all the debris out of the threads and so forth.

You don't want to really put the putty on the threads. The putty goes mostly under the lip of the flange and seals the gap between the flange and the tub. The gasket is what seals the drainpipe to the bottom of the tub and the flange piece needs to draw the two together to compress the gasket a bit and make it seal.


Plumber's putty is an old-school way of doing things. Any new hardware will have a rubber or neoprene gasket that goes between the tub and the fitting under the tub. The seal is actually underneath. I think I see it in your photo.

You may be able to just tighten things up better. A channel-lock or other plier with its jaws in the drain openings works well.

Otherwise I suggest you replace the gasket or simply replace the drain assembly. They're not terribly expensive and you'll have shiny new trim. Skip the putty except maybe to seal under the upper flange for purposes of mildew prevention.

  • The trim did come with a rubber gasket but I didn't use it. Are you saying I should slip it below the trim so that it smashes between the trim and the tub? Aug 27, 2020 at 20:16
  • Nope. Please read again. Also, didn't use it???
    – isherwood
    Aug 27, 2020 at 20:17
  • I revised a bit to make it more clear. There's no nut in your case, but the gasket goes under the tub.
    – isherwood
    Aug 27, 2020 at 20:18
  • I just bought a car, it came with 4 tires... I decided not to use them... Why does the car not move properly? Why wouldn't you use the gasket? Manufacturers like to save money and if it wasn't needed, they would of left the gasket out.
    – Gunner
    Aug 28, 2020 at 1:51

You aren't supposed to use plumbers putty with acrylic tubs, the plastic washer does between the bottom of the tub and fitting(you can see the old one in the pic). Also the threads are supposed to be sealed with teflon tape or pipe sealant(non drying kind).

Finally many new tubs recommend silicone between the top trim piece and tub.

Your leak could be coming from around the trim piece or up through the threads in the bottom fitting since it lookes like you didn't reapply sealant or tape to the black threads. Clean the white threads too and use rubbing alcohol on the tub itself where the trim goes

  • The threads are straight threads (not tapered pipe threads) and don't need sealant of any sort, since the seal is not made at or by the threads. If you happen to have the expensive and corrosion-prone metal version, teflon tape or pipe dope might help to keep them from seizing. But this is clearly a plastic drain shoe.
    – Ecnerwal
    Aug 28, 2020 at 11:41
  • True, mine was brass and it was on the installation instructions
    – redlude97
    Aug 28, 2020 at 15:50
  • Plumber's putty is old school, but the best way to fill the gap under the flange when the radius around the drain hole is large.
    – gnicko
    Aug 28, 2020 at 17:21
  • My understanding is that plumbers putty reacts poorly with ABS and acrylic and companies like Oatey do not recommend them even for the non stain type
    – redlude97
    Aug 28, 2020 at 17:53
  • I don't see anything in OP that indicates this is an acrylic tub. Looks to be porcelain over iron from the picture. On older cast iron tubs (and sinks) there's usually a difference in profile between the flange and the bottom surface around the drain hole. I think we're seeing these differences in profile in the original pictures. The flange is pretty much flat while the area around the drain is rather curved. Putty fills that gap under the flange better than silicone or flat gaskets, but it will stain susceptible surfaces...I think it's the oils, etc. in the putty reacts with the plastics.
    – gnicko
    Aug 31, 2020 at 13:31

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