my house is about 5 years old, a ranch with 2 bathrooms. one bathroom is a ok, but the one in the master bedroom especially in the summer smells like a sewer gas leak slightly. some days its stronger than others. if bleach is dumped in shower and sink drains it helps. i have cleaned out the hair in shower a few times. have checked drain in sink,,,,,any suggestions,,,is there a such thin as a valve for homes with more than one bathroom, a valve in the vent line?