bathroom odor

[House Maven]

I am a professional handyman with the need for some advice.

A female customer says she smells sewer gas when she flushes the toilet in a small powder room.

I don't smell it.

The toilet is an full volume Kohler.

I changed the flapper because it was not working right. Works perfectly now, but she says the smell is still there.

I don't think it is the wax seal because the toilet is rock solid with no water leaks. Also, wouldn't you smell it at other times if the seal was leaking?

Ideas??

[robson]

She may have a partial blockage and when you discharge the toilet the liquid hits the clog and bounces back sending a bubble of air ahead that belches out of a fixture trap. So it could be coming from the sink (mistaken for the toilet). We had a problem similar and it was coming from the shower drain when the toilet was flushed. Snake out the toilet and get rid of the clog.

[Goedjn]

Pour peppermint oil into the DWV stack, cap it, and see if that smell shows up in the bathroom either before or after flushing. If it doesn't then I'd guess she's mis-identifying some other smell as "sewer". Is it only the toilet, or does the sink smell too?

[gotcode]

My downstairs bathroom does this. It ended up being because I would use the toilet down there, but never the sink or shower. Running the shower for 10 minutes every month "solves" the problem.

[nospambob]