Hi - we live in a relatively new home (house was completed in summer of '01 and we were the first residents, moving in the spring of '02) and lately have had a terrible odor of sewage in the upstairs stand-up shower stall - the trap does have water in it and is used quite a bit so there is no chance of it being dried out. Any suggestions on what might be the problem? This house appears to have very good plumbing (from what inspections and people who have seen such things and know them well tell us) so I'm thinking it's not faulty plumbing... at least I hope not!