Musty smell in bathroom?
Our house was built around 1965 and the bathrooms are original. The upstairs bath has a musty smell that is really strong. We stopped showering in it a while ago (a year?) but have kept putting water down the tub drain every so often to keep the trap from drying out.
The other problem is that the toilet seat gets mildew spots very quickly. You can clean the toilet and within a week there are mildew spots on the seat & the underside of the lid. Between the age of the bathroom & the toilet seat issue I felt certain the musty smell was mold or mildew related.
Today I tore out the walls around the tub b/c I figured that's where the source of the mildew was (old house = paper covered sheetrock behind the tile). I found some black mildew/mold, but honestly not that much. I wore a respirator designated for lead paint & mildew/mold, so I was safe.
We plan to renovate this bathroom in the spring when we add dormers to the front of the house but in the meantime, what else could be causing a strong mildew/musty smell in there? It's been this way for months, so I think it isn't just a dead mouse in the wall (and I didn't find any evidence of mice in the interior or exterior walls when I demo'd the walls today). This is the only upstairs bathroom so I'd like to keep the toilet & sink functional as long as possible b/c it's a long walk downstairs for a middle-of-the-night pee break.
I'm almost disappointed that I didn't find huge swaths of black mold/mildew ... Because at least then I'd think, "Aha! I got it!" Any thoughts on where else I should look or what else I should try? I just need to get this bathroom functioning for the next 5 months.