Odor coming from underneath the bathroom sink
I know this has been addressed before and seems to be a common problem but I'm wondering if there is anything new on it. We have a Monaco Dynasty and underneath the bathroom sink, there are two black valves at the top of pipes to let air in but not out. These one way air admittance valves are easy to replace, which I did last year. But I'm wondering how quickly the rubber diaphram can dry out or the unit needs to be replaced, and is there a better quality one that works? Before screwing these in, I checked them to make sure air would blow in, but wouldn't come out. I sealed them with teflon tape when screwing them into the top of the pipe. This year, when we have a fan on, the negative pressure causes the grey water tank smell to come out from under the sink. I got up on the roof to make sure the cap was on properly and no leaves had gotten into the pipe and it looked clear. I have now sealed both pipes with plastic bags and rubber bands to see if it makes any difference. Haven't done the check yet. The only other possibility could be a crack in the piping somewhere around there but haven't noticed any water leaks. Any thoughts?
