A dehumidifier is only part of the strategy for guarding against mold and other allergens, such as dust mites, that thrive
when humidity rises above 50 percent. Keeping water from seeping into your home through a cracked foundation and other structural
defects will help minimize how long a dehumidifier must run. Here's what to do:

Illustrations by Jim Kopp
In the basement
- Patch foundation cracks with hydraulic cement. For dampness rather than leaks, applying a waterproof coating (when walls are
dry) may help.
- Check plumbing pipes for leaks and condensation, including where they meet walls and drains. Silicone caulk can seal small
gaps in concrete.
- Install a sump pump to move water from interior drains or channels to the outside. (If you face water problems in your basement,
read our review of wet/dry vacs.)
- Be sure that the duct for your clothes dryer is properly vented to the outside and isn't leaking. Learn how to vent your dryer.
Outside your home
- Clean and maintain roof gutters, keeping downspouts unclogged and directing water 3 feet away from the house.
- Grade your property so that rainwater flows away from the foundation.
- More-involved fixes include excavating and waterproofing exterior foundation walls and installing drains outside to keep water
from seeping in.
Bath and kitchen
- Run an exhaust fan (available to subscribers) or open a window when showering. Also be sure to squeegee or wipe down shower walls afterward.
- When cooking, use a range hood (available to subscribers) that is vented to the outdoors.