2026-06-16 · Dave Kessler · 4 min read
What Does Mold Smell Like?
If you are arguing about the adjective, you already smell it.
Why this question keeps coming up
Smell is the clue that gets us called, and also the clue people try to delete with candles before a showing.
What it looks like in York County
Rowhome stairs in Downtown and West York move cellar air upstairs, so the smell greets you at the front door even when the colony is below grade. In bungalows the smell can sit in a closet over the crawl. Start at the bottom anyway.
What to do
- Trust a new musty smell after a leak.
- Check the crawl, the sump, and the bottom of finished walls.
- Air the house only if outdoor air is drier.
- Fix the source.
What makes it worse
- Live with plug-ins as a strategy.
- Assume the smell is “just an old house.”
- Ozone the place as a shortcut.
Rowhomes: musty smell.
Questions people also ask
+What Does Mold Smell Like
These pages are homeowner education from Radon Mitigation of York, written by Dave Kessler. They are not a medical diagnosis, a species identification, or an insurance determination. Color does not tell you which mold you have. If someone in the house is sick, talk to a physician. EPA's homeowner guidance treats roughly 10 square feet as the line where many people stop DIY cleanup and call a remediation crew — sooner if sewage, HVAC, or anyone immunocompromised is involved. We are a radon and basement crew. When we are already under a York house we will tell you what we see and what we would do in our own place. We do not pretend a radon fan is a mold remedy.