Here I am again with an "old house" problem! Every time it rains hard my house smells like sewer and I am at a loss as to the cause. I put in a new sump pump, had the septic tank cleaned, and constantly check the two basement floor drains for any back-up, but nothing seems to stop the smell -- it goes away the day after the rain stops! I want to call a plumber, but would really like to have some idea as to what the problem might be before I get someone here so I can feel comfortable about what they say needs to be done. HELP!