Our tri-level house has a master suite on the lower level. The shower is used everyday, the toilet level stays constant. No gurgling or bubbling in the toilet. We are on a well/septic system. We were told that our drain field was failing (by a few different people) so we replaced it. We pumped our tanks last summer. We occasionally get a very strong sewer smell in the bathroom coming up from the shower. It will smell up the whole level...not just the bathroom. If we turn on the attic fan in the highest level (to blow off heat in the upstairs) it will pull the smell in from the shower. We can cover the drain with a plunger and turn on the bathroom fan and this will get rid of the smell. What do you think is the problem and will it be an expensive repair??

Perhaps another fixture is siphoning the water out of the shower drain trap. This will happen if the shower is improperly vented or not vented at all. It can't be the trap drying out if you use it every day, therefore something is causing the water to take leave of the shower trap.

It is also possible that there is a crack or other defect in the trap, or even that there is no trap at all. If there is access to the the underside of the shower drain then it should not be a difficult or expensive fix. If your lower level is on a slab, then things get quite a bit more complicated.

As Richard suggested, check for a vent first, and if it exists make sure it is working and not obstructed.

I concur with my fellow posters. Venting or trap is the issue here.

You will need to get to the trap to see if you have one. Also you will need to install a vent if it does not exist. What determines if its a hard fix or not is what is below the shower. If its on a slab, you will need to dig, not a pretty job. If you have access to the drains Not such a big problem. Depending on the access and where you live will determine the cost. As this varies all over the country.

Well, you were all absolutely correct. I had a plumber come out and there is no trap or vent in the shower. The shower will have to be removed, the concrete slab cut into, the wall cut into and a vent needs to be installed....yuk! Thanks so much for responding to my post!

Sorry to hear the extent of the cure, but you'll enjoy living without the odor. Glad you found out what was causing it. (Although the "plunger" fix WAS pretty cheap and effective )

Nice to see we get one right once and a while!