A musty smell in one room usually means there is moisture somewhere you cannot see, and mold or mildew has started to grow. Hidden plumbing leaks are a common cause, but poor airflow and water coming in from outside can also create that damp, earthy odor.
Why Moisture Smells Musty
Mold and mildew give off gases as they grow. These gases have a stale, earthy smell. You may notice it most when you first walk into a closed room, or when the weather is warm and humid. The smell often comes before any visible mold.
Plumbing Sources to Check
- Pipes inside walls shared with a bathroom or kitchen
- Under sinks and behind toilets
- Around the base of a tub or shower
- Near the water heater or washing machine
- Ceilings below an upstairs bathroom
Look for stains, peeling paint, warped baseboards, or flooring that feels soft. Use your nose to find where the smell is strongest, and check that spot first.
Non-Plumbing Causes
Not every musty smell comes from a pipe. Roof leaks, window leaks, and poor drainage outside can let water in. Closets and basements with little airflow can trap humidity. Damp clothes or towels left in a hamper can also create odors.
A simple check is to see whether the smell stays the same in dry weather. If it does, a plumbing leak is more likely. If it is worse after rain, outside water may be the source.
Why It Should Not Be Ignored
Moisture that keeps feeding mold can damage drywall, wood, and insulation. Mold can also bother people with allergies or asthma. Covering the smell with air fresheners does not fix the cause.
If you think a pipe is to blame, tracking down the source of the moisture is the best first step. For musty odors near drains or fixtures, you can ask a plumber to check those areas at (833) 603-1840.