I was cleaning the shower drainage pipe (removing hair etc) in the upstairs bathroom and I can see water around 1 foot deep. See the pic.enter image description here

Is that normal? Shouldn't the pipe be empty? If water stays stagnant like that, it can't be good.

If this is a problem, how do I fix it?


Yes it's normal and what you want. It's called a P-trap and the water sitting in there seals out the sewer gasses.

My ASCII P-trap:

                  \ /
                  | |
   __________     | |
   _________ \    / /

The asterisks would be the water that forms the stopper.

In an empty home or in drains that are infrequently used (such as a basement) you these traps can eventually dry out from evaporation and let sewer gasses seep in.

In your case, if you aren't going to use the shower for months on end, I suppose you could add a drop of bleach to the drain. If the shower is used semi-regularly, there should be no issues at all.

  • Thank you for your answer. You answered exactly what I was asking for. Before I accept, one question I have is that there are a few baths and sinks that I don't use for months together. Is it advisable to open the tap once in a while or how is the bleach going to help?
    – coder net
    Sep 19 '11 at 11:28
  • 1
    The bleach suggestion was in case you were worried about grime/slime sitting in there. As for baths/sinks you don't use for months at a time, it certainly wouldn't hurt to turn the tap on for a minute once a month or so. As to whether or not they'd actually dry out in that time would depend on your climate/humidity.
    – DA01
    Sep 19 '11 at 13:35
  • 1
    what will happen if they dry out.. is it certain that the sewer gases will seep into the house? any problem apart from a potential smell?
    – coder net
    Sep 19 '11 at 13:47
  • You'd notice the smell long before any potential other issues (of which I can't really think of any...I guess I wouldn't light up a smoke in a closed bathroom full of sewer gas, I suppose)
    – DA01
    Sep 19 '11 at 15:48

You can get small sewer flies if drains not used for a while easy to eradicate just put bleach down drain every month, leave overnight they are harmless but not nice to have in your home

  • Hello, and welcome to Home Improvement. Thanks for the answer; keep 'em coming. And, you should probably take our tour so you'll know how best to contribute here. Feb 26 '20 at 11:27

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service, privacy policy and cookie policy

Not the answer you're looking for? Browse other questions tagged or ask your own question.