The first thing to do is to make sure that all of the traps in your drains have water in them. If there is a drain that you seldom use, such as a shower or sink that rarely get used, run water into that drain for a bit. That may well clear up the problem.
The other thing to do is to check under your house and make sure that there are no leaking drain pipes there. Leaking pipes underneath your house are not the responsibility of the city. You should contact a plumber to repair those problems. If these checks do not tell you the problem, please call our 24-hour line at 281-275-2450.