We just got our master bathroom remodeled and now there is a sewer smell every time we walk into the bedroom. We are on a septic system and we are on a slab. I have narrowed the smell down to the shower drain. The contractor ripped the old fiberglass shower out, built a concrete shower pan and replaced the drain. He did not do anything to the trap as it is in the slab nor did he move any plumbing; he only replaced the drain. I looked into the drain and there is water, but I don't know exactly where the trap is in relation. Could there be debris in the trap that is causing the gas to escape? Thanks for any advice or other thoughts!