If you have had the p-trap drained and didn't get the odor, you might be chasing the wrong ghost.Strong sewer gas smell from the drain can be evaluated by many ways, but one trick is to scientifically track the problem. Professionals use sniffers to detect if the gas is Hydrogen Sulfide, or ammonia, or chloridic or acid, and they are very accurate - and non-destructive. The vent fan may or may not have been the right way to test for the odor, if it was short term, but still, you are getting desperate and want HELP. So try scientific approaches. The probable first Best Management Practice (BMP) is to call the odor a health and sanitation problem, go to your Phoenix building department, get a copy of the building permit, and verify that you are connected to Public Sewer. (If you aren't - the building department will likely tell you that as Public Servants they aren't allowed to help you privately). The Building Department will try to send Public Utility workers tracking all through your house for days and days, (if you try to get the City to do work for you) but just verify the connection to Scientifically eliminate Septic System odor ghosts. Do you have a slab floor? Is there only the one shower, or is there another, but it isn't offensive? If it is a slab floor, is there a hint of bad odor in the laundry (but just not as strong)? Ask the Building Department for a list of five LICENSED contractors that the City contacts to do odor sniffing and rectification, and get estimates from them. If you need more help, e-mail me at email@example.com
: After showering we have a strong sewer gas smell in the shower. We have had a plumber clean out the lines in the shower, tub and vent pipe - no blockage. He has drained the water out of the ptrap - no odor. After reading several questions posed to you, you had mentioned a vent fan might cure the problem - well we installed a temporary retrofitted duct fan to see if it would work - we used a 6in in-line duct fan with reducers to fit our 2in. vent pipe - it didn't work - please help any suggestions on what to try next. We are desparate for a solution - Our plumber, as a last resort, is suggesting we rip out the shower to hopefully locate the problem - can we avoid the expense of having to rip out the entire shower to locate the trouble. We live in Phoenix, AZ and the home is 10 years old. HELP!