Hello, We just bought a house 3 weeks ago. After about one week, we had a VERY strong smell start coming from the master bathroom corner shower upstairs(which subsequently went away 90%). There are two bathrooms upstairs, the second bathroom and the rest of upstairs fixtures were not affected.. Only corner shower. After a week of the shower smelling, the smell started to come out of the kitchen sink downstairs slowly.. The kitchen sink is almost directly under the corner shower. The smell comes out of the kitchen sink more when the water is being run. Now, a week after the kitchen sink, the basement sink started to smell as well. The basement sink is not under the kitchen sink, it is quite further away and connected to a separate drain pipe. There are two main drain pipes in the basement. I've previously tried to open both cleanouts in the basement and smelled inside, but that smell was not there. I also tried a drain snake almost everywhere without finding anything. The smell is coming from the top downward somehow? I am aware that when water runs, air is sucked from the roof through the vent and comes down.. I can't figure out is where this smell is being generated from however. I can't describe the smell.. it is not a public sewer smell. The best I can say is that I've smelled the same exact smell in other people's kitchen sink at the very bottom of the sink. However in other sinks this smell is very faint and you can barely notice it. Plumbers don't seem to want to come out to take a look, they say if it's not plugged they can't do anything. I've inspected the traps and they have water, so I don't know how the smells comes out of there, does it go through water?? Any ideas what else I can try ?