[usmcdcc]

Hi all... novice home owner here looking for some help.

I have a 4 yr old home, 2.5 bath. .5 on the main level and 2 full baths upstairs.

In 1 of the 2 upstairs baths, I get a VERY strong odor of septic/methane... something.

In this bathroom, I have a toilet (no visable water leaking on the floor and seems pretty well seated), a sink (no leaking) and a tub.

I am not sure where it is coming from in the bathroom, but I know (assume) that the stink is from 1 of these 3 sources. How do I detect and solve?

With the toilet being stable and the sink not leaking, I want to look to the tub. I would assume a faulty P-Trap would lead to water damage on the floor below, but this has not occured at all.

So, where do I start? Obvioulsy, I would raher not tear through the wall/ceiling to get to the tub pipes if I don't have to.

Thanks in advance...

~David