Signs of Mold in Your House
Mold needs moisture. Most signs of mold are really signs of a moisture problem.
Common signs
- Musty, earthy odor, especially in closets, basements, or when the HVAC runs.
- Visible spots — black, green, white, gray or orange — on walls, ceilings, grout, or wood.
- Water stains or discoloration on ceilings and walls.
- Peeling paint, bubbling wallpaper, or warped baseboards.
- Condensation on windows and pipes; indoor humidity regularly above 60%.
- Recent leaks or flooding, even if they looked dry quickly.
- Allergy-like symptoms that improve when you leave the house.
Where hidden mold grows
- Behind drywall near plumbing, showers and exterior walls
- Under sinks and behind appliances (dishwashers, refrigerators with ice makers)
- Attics with roof leaks or poor ventilation
- Crawl spaces and basements
- HVAC ducts, drip pans and air handlers
- Under carpet and padding after water events
What to do next
Control humidity (EPA recommends keeping it below 60%, ideally 30–50%), fix leaks promptly, and dry wet materials within 24–48 hours. If you smell mold but can't find it, a professional inspection can locate hidden moisture.