Hello. I have replaced all my plumbing through the house and new sewer pipes under the basement floor to the street. The house still smells like sewer gas. I filled the tap in the basement drain up and a week later it was gone. I had the house smoke tested and a camera run down the trap to the street. Everything looked good. No leaks. On plumber said it might be a venting issue. What do you think? Have any ideas?