I recently moved from Southern California to the Pacific Northwest, just outside of Seattle. I rented a house and have been living in it for ~3 months.
Just earlier today, in the seldom-entered guest bedroom, I noticed some white fuzzy substance under the bed. I've never seen anything like this in any home in which I've previously lived.
Does this look like mold? The carpet does feel somewhat damp though it's not outright wet.

enter image description here

  • looks like mushroom mycelium, not mold
    – jsotola
    Sep 21, 2019 at 3:06
  • Yes it does look like mold or at least mildew, a precursor to mold. The good news is, it's not "black mold". All mold is potentially harmful, but black mold is the one that scares most people. it needs moisture. You likely have a leaking window or something, or your floor is wet from underneath. Is this in a basement room? If it is, and the floor under it is concrete, it could be "efflorescence", a crystalline growth from wet concrete under the carpet. have it tested, and find out why the carpet is damp right away.
    – JRaef
    Sep 21, 2019 at 3:07
  • It's hard to tell from the photo. I'd agree that from what can be seen, some kind of mold/mildew is likely. However, if there is concrete directly underneath, there's a small possibility it's efflorescence from the concrete. If you gather a small sample and wet it, efflorescence will dissolve instantly, while a biological substance won't. Oct 22, 2019 at 18:39

1 Answer 1


It looks like a fungus to me see the light fuzz. Here in the PNW it is fairly common in dark and damp areas. I have seen this on carpet and Sheetrock many times. Even though our humidity is not extreme like back east we do have many mold and fungus problems because of our moderate temperatures and year round moisture. I find the least offensive method to kill it is a 3% hydrogen peroxide and water solution will kill it (use caution as it can discolor some materials even at this dilution) but it doesn’t stink like bleach. Note this will also take care of mold & mildew you may find in your window tracks& sliding door tracks that very commonly grow “gunkies” in our area.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.