Bathroom air vent drip

Question

I have a constant drip coming from the air vent in my downstairs bathroom. After one week it has filled a bucket full of water. There has been no snow or rain in my area. The air conditioning hasn't been on nor has the heater. Any ideas where it is coming from?

Answer 1

There's a few possibilities, and it's hard to pick one given the area

1. If the inside of your house is warm and moist, and the attic space or outside of your house is cold, the water could be condensing inside the pipe.
2. There could be a plumbing leak in the space above the fan that's leaking out the fan as a path of least resistance.
3. You could have some other vapor barrier issue in the area around your fan that's causing condensation.

Answer 2

I had a similar problem last year. My problem turned out to be condensation from uninsulated exhaust pipes running through the attic. I went in the attic and used duct insulation on the pipes and haven't had the problem since.

See this post.