I'm doing a bathroom reno and will be removing the bathtub and shower, and they will be out for quite some time. Because of this, I want to cap off the 1.5" and 2" PVC drain pipes (rather than stuff a towel in them or something similar). Can I simply put a PVC cap on without any solvent, or will that leak sewer gasses?

3 Answers 3


Yes. DWV pipe caps fit quite snugly, without glue, and will not pass any detectable amount of vent gases. You had better be sure that those drain lines will never be subject to filling with waste water, condensation, etc. If you're planning to glue-up some new drain/vent piping as part of your project, you'll be needing something like expansion plugs to properly water-test your work, and those will work excellent as temporary pipe plugs.

  • 11
    The risk with this approach is that it becomes very easy to forget a cap that is not glued, and then to install the bathroom tiles over the wall. Then, once the work is done, with a little pressure or some jiggling, the cap come undone and the wall has to be demo'ed and redone.
    – Jeffrey
    Commented Jan 9, 2023 at 20:34
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    @Jeffrey label it clearly then - Sharpie/permanent marker is good, or something with clear visibility. I've seen coloured ribbon used for this and it stands out.
    – Criggie
    Commented Jan 9, 2023 at 21:14
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    After putting on the cap, write on it and then put a baggie and rubber band over it to make it obvious that it is temporary.
    – Nelson
    Commented Jan 10, 2023 at 1:02
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    Hang a big "remove before flight" tag on it?
    – fectin
    Commented Jan 10, 2023 at 13:10

A baggy and a rubber band should work.

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    It sounds too simple, but I did this for almost a year without issues.
    – blarg
    Commented Jan 9, 2023 at 11:21
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    If there is an adjacent or physically higher source of wastewater which could backflow into this bathroom's piping then this solution is not optimal.
    – MonkeyZeus
    Commented Jan 9, 2023 at 14:51
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    @MonkeyZeus If there are backflow problems in the drain/vent pipes, then the OP has some REAL problems. Commented Jan 9, 2023 at 16:06
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    If the problem develops after slapping on a baggie and rubber band then OP will not be a happy camper. At least with a proper seal, the backup would make itself known in a different sink, bath, or toilet instead of spewing past a baggie. Chastising someone for having REAL problems is not much of a condolence for having to clean sewage off of a living space.
    – MonkeyZeus
    Commented Jan 9, 2023 at 16:23
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    What @SteveWellens is saying is not chastising anyone, but the fact that this scenario is so extremely unlikely that you realistically cannot work as if this will happen. Rubber band and baggie. If you get sewage backflow, hire someone to clean it and then contact the city sewage department to fix the problem, and then cap it off and seal it.
    – Nelson
    Commented Jan 10, 2023 at 1:01

Oatey makes a number of "Gripper" plugs for many sizes of pipe and fittings. I have seen them available in big-box stores. There is a gasket and a screw you turn to tighten the plug into the end of the pipe/fitting, it is air/pressure tight (to a point) and it can be easily removed later.

They look like this: enter image description here

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    No fear of deforming the pipe? Commented Jan 9, 2023 at 16:05
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    I guess it depends how hard you crank down on the screw, but in my experience with them I haven't had any deformation.
    – SpikedCola
    Commented Jan 9, 2023 at 16:19
  • I had seen these (and am using one to plug the toilet drain, as I don't need to remove the flange to use it), but they are (considerably) more expensive than a simple PVC cap
    – mmathis
    Commented Jan 9, 2023 at 16:58
  • These are also used for plugging pipes when doing leak tests for inspections, so it may be worthwhile to have a couple of them, at least if you plan on doing any extensive work that you care about checking that it doesn't leak. Commented Jan 12, 2023 at 0:42

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