Signs of Mold in Your House: A Nashville Checklist

What does mold smell like, and should you trust your nose?

Yes, trust it. EPA's training for investigators says moldy or musty odors should alert them to the possible presence of mold, and that damp or musty smells suggest water is or was present and growth is likely. Most people describe it as earthy, stale or like a wet basement. It is often strongest when you first walk into a closed room or when the HVAC kicks on.

A smell with no visible growth usually means mold is somewhere you cannot see: behind drywall, under flooring, in the crawl space or inside ductwork. Pay attention to where the smell is strongest and when. A smell that comes up through the floor registers in summer points below the house. A smell in a single closet that shares a wall with a bathroom points to a plumbing leak.

What does visible mold look like?

Mold can be black, green, gray, white, brown or orange, and it can look fuzzy, slimy or like a flat stain. EPA reminds investigators that mold comes in many colors, not just black, and that some carpet stains can look like mold. Color does not tell you how risky the growth is; our article on what is true about black mold explains why.

Common visual clues include:

• Spotting or speckling on drywall, ceilings, baseboards or the backs of cabinets.
• Yellow or brown water stains that keep growing or never dry out.
• Paint that bubbles, cracks or peels, and wallpaper that lifts at the seams.
• Warped, cupped or soft flooring, especially near bathrooms, the kitchen and exterior doors.
• Fuzzy growth on stored items, leather shoes or furniture in a closet or basement.
• Persistent condensation on windows, pipes or ducts.

Where does mold hide in a house?

EPA lists the hidden spots investigators check: the back side of drywall, wallpaper and paneling; the top side of ceiling tiles; the underside of carpets and pads; damp areas behind walls and in crawl spaces; and acoustic liners inside ventilation ducts. It can grow in dark areas on surfaces nobody looks at.

EPA also warns that investigating hidden mold calls for caution, because disturbing a moldy area can spread mold through the building, and opening an air handler can send dust and mold into the air. If you suspect growth inside a wall, do not start cutting holes. A professional will use a moisture meter, which EPA notes investigators rely on to find wet areas in carpet, wallboard, wood, brick and concrete, before opening anything. Growth behind finished walls is covered on the mold in walls page.

Room by room: where to look in a Middle Tennessee home

Crawl space

Many houses around Nashville sit over vented crawl spaces. In July and August, humid outside air flows in and meets cool ductwork and floor framing. Look for dark spotting on joists, sweating ducts, wet or torn vapor barrier, standing water after storms, and a musty smell in the rooms above. The guide to crawl space mold in Middle Tennessee goes deeper, and the Nashville crawl space mold service page covers removal.

Attic

Check the underside of the roof deck for dark staining, especially around vents, chimneys and bathroom fan ducts. If your air handler is in the attic, look at the drip pan and condensate line; EPA advises keeping drip pans clean and drain lines flowing. More on this on the attic mold page.

Basement

Older and hillside homes often have basements. Look for white powdery deposits or damp patches on block walls, rust on the bottom of metal shelving, musty boxes and a line of staining along the base of the walls after heavy rain. See how to keep a basement from growing mold and the basement mold service in Nashville.

HVAC system

EPA notes that moisture can collect in ventilation systems through poor drainage from the condensate pan. Signs include a musty smell when the system starts, visible growth on vent covers or around the air handler, and a drip pan with standing water. EPA advises against running the system if you know or suspect it is contaminated. See duct and HVAC mold for what happens next.

Kitchen, bathrooms and laundry

Check under sinks, behind the refrigerator and dishwasher, around the toilet base, at the bottom of shower walls and behind the washing machine. Soft drywall or a loose floor tile near a fixture often means a slow leak.

Bathrooms without a working exhaust fan are a frequent source of trouble. If the mirror stays fogged long after a shower, or black specks keep coming back on the ceiling above the tub, moisture is not leaving the room. Run the fan during and after every shower, and check that it actually vents outdoors rather than into the attic.

Windows and exterior walls

Look at the bottom corners of window frames and the drywall just below them. Water that gets past failed caulk or flashing often runs down inside the wall and shows up as a stain near the floor, well below the actual leak. Bedrooms on the north side of a house, with furniture pushed tight against an outside wall, can also stay cool and damp enough for growth to start behind a dresser or headboard.

Is your house at higher risk?

Some homes deserve a closer look:

• Homes with a flood history. Parts of Nashville flooded in May 2010, when the Cumberland River crested at 52.55 feet, and again in the March 2021 flash flooding. EPA says that if a home flooded and could not be dried within 24 to 48 hours, you should assume mold growth. Metro Water Services publishes FEMA flood maps, and notes that properties outside the mapped flood zone are not guaranteed to be safe from flooding.
• Homes with high indoor humidity. EPA recommends keeping humidity below 60 percent, ideally 30 to 50 percent. A small hygrometer from a hardware store will tell you where you stand.
• Homes with a past leak that was patched but never dried. Mold growth often shows up weeks or months after the leak is fixed.

What about symptoms?

Be careful with this one. EPA says mold exposure can irritate the eyes, skin, nose, throat and lungs, and that people with asthma or weakened immune systems should stay away from moldy areas. CDC notes that symptoms linked to mold are nonspecific, so they can have many causes. If you or a family member has health concerns, talk to a health professional rather than relying on a mold company or a home test kit.

You found some signs. Now what?

1. Find the water. Every mold problem is a moisture problem first. Fix the leak or the humidity source, and dry wet materials within 24 to 48 hours where you can.
2. Measure the visible area. EPA says a homeowner can usually handle less than about 10 square feet. Larger areas are a job for a professional.
3. Do not disturb hidden growth. Leave walls closed and the HVAC off if you suspect it is involved.
4. Decide whether you need an inspection. If you smell mold but cannot find it, an inspection is the logical next step. Angi's 2026 national data puts a mold inspection at $303 to $1,075, averaging $689, and a mold test at $250 to $500; prices in Middle Tennessee vary. EPA says sampling is usually unnecessary when growth is visible, so ask what any test will tell you before paying for it. Our comparison of inspection versus testing can help, or go straight to a mold inspector in Nashville.
5. If you rent, tell your landlord in writing. Metro's mold handout says landlords should make repairs promptly and points tenants to Metro Codes and the Metro Public Health Department. See what renters in Nashville can do about mold.

The same checklist applies across the region, from Sumner County to Rutherford County. Homeowners can find a mold inspection in Gallatin or crawl space mold help in Smyrna on their local pages.