How do I get rid of a musty smell in my basement?

Concerns & risks

Your basement smells like an old wet sock.

The smell spreads to stored stuff and can mean hidden mold.

Causes & evidence

Basements are cool and humid, ideal for mold and mildew. EPA humidity targets: humidity and mold.

What to do

1. Measure humidity. If above 60%, get a dehumidifier sized for the space.
2. Point gutters and downspouts at least a few feet from the foundation.
3. Move cardboard boxes into plastic bins, off the floor.
4. Clean visible mold on hard surfaces with detergent and dry.

Common mistakes: Masking the smell with fresheners doesn't fix humidity. Don't store cardboard boxes directly on the floor. Fix water sources before running a dehumidifier forever. Walk the basement after rain and look for damp walls, puddles or white mineral crust, which show where water enters. Clean gutters and make sure downspouts send water away from the foundation. Aim the dehumidifier at the space and empty or drain it regularly.

Speed Man tip: Water seeping through walls or floors? Talk to a waterproofing pro.

Wrap-up: Musty means too much humidity. Run a dehumidifier and keep humidity below 60%. Fix gutters and move stuff off the floor.