re: Plumbers of the OT: Sewer gas smell in the bathroom.

your complaint is fairly common actually. water sitting in drains in unused houses for weeks literally turns into sewerage smelling mush like jelly

first fill up every sink and tub full of hot water then after its full, pull the stopper and let it flush out the drain, then go around and pour a cup full of bleach in each drain and leave it sit overnight like that.

also check under sinks for water leaks and mold rot and behind as well as under the toilet tank for black mold, in empty houses they can sweat and grow mold that needs to be scrubbed off with hot soapy bleach water to clean and kill it.

its a good idea to put a little bleach in any drain that sits unused for a long time so it kills the mold growing in the p-trap there