AAV and sewer smell

Would a bad AAV cause a bathroom or laundry room to omit sewer smells? We are getting a sewer smell a few times a week around 7pm.

It looks like the house has two venting systems. One goes through the roof and the other terminates in the attic with an AAV (it's about 1.5 feet above the insulation).

Last night I went to the attic and unscrewed the AAV and the odor just morphed out. I noticed the AAV had some condensation under it.

Is it coincidental that around 7pm a few times a week the water treatment plant smells really bad too? It's about 6-7 miles away from the house. I sometimes notice when driving home from work that the air around the treatment plant is awful until I'm a 1/2 mile away.

I'm thinking if worse comes to worse of installing a whole house p-trap as the house is on pilings and plumbing is very accessible.

An AAV is a one-way air valve...it will let air in only (if it is working properly). If it is already up in the attic, the best choice would be to put a T on the existing vent going through the roof, and connect that one to it. You might need to upgrade the size of the pipe going through the roof. Condensation is probably normal, as the air is humid in the vents and the attic this time of year is likely cold.

A whole-house p-trap isn't necessary, and could be a source of hassles in the future.

So would a bad AAV create sewer smells in the house? For a fast fix, I thinking of replacing the AAV for $16. Should I pour bleech in the vent line or anything?

If the AAV has failed, then the attic would smell and from there, the smells could migrate into the house. It probably isn't the AAV, but I would not just replace it, I'd spend that money and connect it to the other vent so it goes outside like it should. Again, an AAV is a one-way vent...only in, so no sewer gasses should exit the pipe. Some fixtures need to push air out the vent to work, and then you'd have problems with the drains.