When we renovated a few years ago, I asked the plumber who was doing the rough-in to put traps on all the drains that needed them. He did this but skipped a couple (bad plumber ... there were other 'below code' things that he did but I've since had them all repaired). The basement drains that I could see had traps so I went ahead and finished the downstairs bathroom, including a shower stall. Occasionally, we smell sewer gas coming from the shower drain so obviously this was another trap he didn't install.

I don't want to tear up the shower and floor so I was wondering if it is OK to put a trap along the line under the next room (that room isn't finished yet).

If so, is there a specific type of trap needed? Any advice on what to watch out for? (I'm a standard DIYer ... bit of experience, willing to learn, etc.)

P.S. One good thing -- we have a wood basement ... no concrete.

 

To make sure that the shower has no trap pour water down and look down the pipe and see if you have any standing water, if so you have a trap, if not you don't. If you don't have a trap you will have to remove the shower base and install one. The line that you want to install a trap in I can't say because I don't how things are hooked up. Sorry for the negative.

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"If all else fails, read the directions"

 

If you didn't have a p-trap you would "always" smell sewer gas. You may have a venting problem, with another drain siphoning the trap. When you finished the bathroom was the plumbing vented properly?

 

I think it's a venting issue too. If the shower was totally untrapped you would hear water echoing loudly thru it when you used another fixture and it would stink up the bathroom all the time. Does it stink when you're taking a shower or after? How often does it stink?

 

we have that problem in our guest bath, if i do not run the water every few weeks the water in the trap evaporates.

 

After a shower ... about 5 to 10 minutes after the water has drained. I don't hear water echoing though.

There were some venting issues ... a city inspector pointed them out to me last year. I had a plumber in last week and he fixed everything up (guess I should've asked him about the shower huh? ... but you guys are cheaper for advice ;-) I think the sewer gas smell is worse/more frequent since he repaired the main venting problems.

Re: 'pouring water down the drain' ... I can see that the pipe angles off to the right (towards the next room I referred to) and doesn't have any standing water below it. That's why I assumed there is no trap.

Again, assuming I can trace the shower drain pipe, is it OK to put the trap in this line? This would put it about 6 to 8 feet away from the bottom of the shower. As I said, the next room is not finished yet and I could easily remove some of the floor to get at the pipes.

 

Under most codes and good practice you can't put a trap 6 or 8 feet from the fixture, the trap must be in the vicinity of the fixture; with a shower it must be directly below, sorry for another negative.

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"If all else fails, read the directions"

 

It's also not good to double trap things.

I still think it is a venting issue. Run a piece of rope down it after it's not been used for a while and see if you don't find a trap. It could be a drum trap, or a U-trap under the shower.