sewer gas

hi just bought a new house 6 mts ago. stong smell sewer gas when we take a shower sometimes most of the time at night both bath rooms. when my wife uses the dryer smell is strong sometime not everytime if we open a window smell goes away. hope someone can help tks jim

Run the dryer (on cold, to save $$) and see if you can pin down the fixture(s) the gas is coming from. The dryer pumps a lot of air outside, and that air has to be replaced from somewhere. In your case it appears to be replaced by sucking gas out of the sewer, which may be the easiest makeup air to find if your (new!) house is really tight. Opening a window near the dryer is the easiest way to fix this, as you've found.

Unfortunately, this doesn't explain the smell when you're taking a shower, but you're not alone. There's a really interesting thread on this forum describing a similar problem, with no solution found yet.

Mikey , question please

are you saying a properly plumbed trap could empty by using a dryer ? thank's Tool

If you had a perfectly sealed bathroom with a dryer in it and turned it on it might suck gas through the trap, but who has that? I would guess that there is an open DWV pipe somewhere near by.

I bet since you have a dryer there you also have a washer and I'll bet the washer is not trapped. Is there just a pipe coming up through the floor for the washer drain?

Tool - That's what I'm saying, but it's totally unsupported by any hard science that I know of. I do know that today's tightly-wrapped and -sealed houses don't breathe like the older ones did. An electric clothes dryer typically wants to exhaust around 200 cfm -- enough that some mechanical codes (UDC, IMC and some state codes) require makeup air vents -- mostly to prevent backdrafting of gas-fired appliances, I think, but also to allow the dryer to function efficiently. I don't know how much of a partial vacuum is required to suck sewer gas back through a trap -- clearly it won't drain a properly plumbed trap -- but it'd be a nice experiment.

thank's Mickey

Live and learn, that's a possibility, maybe