Marine-layer humidity makes bathrooms ground zero for mold. Eight practical fixes you can do this weekend.
Why bathrooms are ground zero
Showers can push relative humidity above 90% in under 10 minutes. Without proper exhaust ventilation, that moisture saturates drywall, grout, and the back of vanities — perfect mold habitat.
The 8-step prevention playbook
1. Run the exhaust fan during showers AND for 20 minutes after. 2. Verify the fan ducts to the exterior, not into the attic. 3. Squeegee shower walls after each use. 4. Re-caulk tub and shower seams annually. 5. Inspect under-sink plumbing every six months. 6. Keep humidity below 55% with a hygrometer. 7. Replace vinyl shower curtains every six months. 8. Test annually if you notice musty smells.