We have a 2 story home, 1 year old, crawl space, no basement. Our main level 1/2 bath is the only bathroom in the house that smells like a sewer when the water in the sink is turned on. I can usually only smell it when the water is running, and it seems to be getting worse over time.

We recently had a plumber at our house who looked into another problem. Our master bath toilet tank upstairs was sounding like it was filling up with water when you would run water or flush in another part of the house, or in the sink in the master bath. The plumber said the seals were bad or something so he replaced all of them and then adjusted the tank water level some. It's better but not great. I've tried reading all of the threads on this subject before asking... but is there a vent that is stopped up that I should try looking at or do I need to pour bleach down this sink? It's definitely the smell of a sewer and not a foul egg smell.