Stinky Bathroom - Need help

[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

[thedcdude]

If all fixtures are secure, it sounds like a vent problem.
Your P-traps could be getting sucked dry. Are you comfortable going up on the roof? If so check the vent pipe for any obstructions. Squirt some water from your hose down the vent pipe to try and blow it clean. This is an inexpensive first try.

Have you tried cleaning the drains in the tub and sink. Even though they aren't blocked, there could be something smelly stuck in the P-traps. I would also open the top of the toilet tank and check that out (in case you have some friends with a sick sense of humor).

[jnaas2]

Before you climb up on the roof go to the bathroom thats causing the smell and run some water into all the fixtures. Then have someone go flush the toilets in the other bathrooms and see if the drain makes a gurgling sound in the bathroom with the smell, if it doesnt then the problem more then likely isnt a vent problem. If you dont get a gurgling sound from the toilet or the sink I would say that the wax ring on the toilet has failed and its letting in air and also letting out the smell. If you know someone who has a combustible gas detector they can find the source of the methane smell coming from the sewer line

[dlfinn99]

If your in a cold climate,,I would check for vent blockage,,ice or snow,,,,ice can form inside the wall at times,,,have someone run the water to the fixtures while listening down the vent