Common smells and where to look
| Smell | Likely area | What to check |
|---|---|---|
| Sour or mildewy | Shower surround, tub caulk, bath mat area | Soft or discolored caulk, grout lines, the wall behind the tub |
| Sewer-like | Floor drains, unused sinks, a washer standpipe | Whether the trap has water in it; pour in water and recheck |
| Damp-towel smell | Laundry closet, washer door seal | Standing water, a gasket with residue, a dryer vent that does not exhaust well |
| Musty and stale | Exhaust fan housing, ceiling | Whether the fan runs, moves air and ducts outside |
Apartment laundry room with a row of washers and dryers. One example of what this stage can look like; it is not a job connected to this site.
Why moisture lingers in a vacant bathroom
An occupied bathroom gets regular use and regular ventilation. A vacant one does neither. Water left in the washer drum, a wet bath mat, or a leaking toilet supply can stay damp for weeks, and caulk that was already starting to fail gives mildew a place to grow in the dark.
The exhaust fan matters more than most people expect. A fan that is clogged, disconnected from its duct or venting into an attic leaves humid air hanging in the room. Hold a tissue to the grille while the fan runs; if it does not pull the tissue, the fan is not doing its job.
Laundry closets are similar. A dryer vent that is crushed or long and lint-clogged can push damp, warm air back into the closet, so the smell seems to come from the washer when it really comes from the vent.
A check-and-clean routine
Run the fan and the water
Check that the fan pulls air and that each drain empties without gurgling.
Refill every trap
Pour water into floor drains, tub drains and unused sinks so the seal is restored.
Inspect caulk and grout
Remove failing caulk, clean the joint, let it dry, and reapply a mildew-resistant product.
Clean the washer and its hookups
Wipe the door gasket, run a cleaning cycle, and check the supply hoses and standpipe.
Clear the dryer vent
Disconnect and vacuum the duct, and check that the exterior flap opens freely.
Common questions
Is bleach the right cleaner for bathroom mildew?
It is a common choice, but products vary in what they are safe for. Never mix cleaners, ventilate the room and follow the label on the product you use.
General information for Aurora, not a quote or professional advice. In an emergency, call 911.