The sink in my bathroom has a sewer type odor that comes from the drain. It's not constant, usually in the evening and more so on warmer days. I have tried cleaning it with vinegar & baking soda or bleach, but that only works temporarily. The drain is not slow so I don't think there is any type of clog. I live in a condo so I am not sure if this is an inside problem in which I would need to call a plumber or if it is something outside of my walls in which the HOA would use their plumber. The sink is against a wall shared with another unit. I don't trust the management company that our HOA has so I was just wondering if anyone had any idea what the problem might be before I try calling them.