enter image description hereWe purchased our house last August and I don't know how old the carpet is but it's definitely been around for a while.

Earlier this year, these little black dots started showing up in one specific area of the carpet. The area is near the door to our patio so of course it could be from the dog... but they are almost identical in size and color.

We don't wear shoes in the house (if that matters), and it seems like they show up after it has rained. I wipe the dog's paws before she comes in if it's wet out and I haven't seen anything come off on the towel that could be the culprit of the black spots.

We had the carpet cleaned six months ago and the spots came up, but they have started to return in new areas over the last week.

I'm wondering if they are some sort of mold spores that are coming up from the carpet padding? Is that even possible?

Has anyone had any spots like this appear on their carpet? We are going to get the carpet replaced with hardwood soon but I would still like to figure out what is possibly causing this.

  • I presume this is a first/ground floor, since the dog comming in was an initial culprit. Do you have access to the underside of this floor (i.e. unfinished basement or crawlspace)? If so, check what's underneath. If you've got moisture on the joists or sub-floor from below, then you're getting water seeping through at a minimum, and possibly mold growth. If there is a finished ceiling below, it may be worth tearing into it a bit (neatly, of course, with repair in mind) to find out what's going on between the finished surfaces.
    – FreeMan
    Commented Jun 22, 2020 at 13:15
  • Are the spots generally near a wall? Is it an exterior wall that could be leaking, or an interior wall with plumbing (supply and/or drain) that could be leaking? Edit your post to include the answers to these questions, as that will help you get a better answer.
    – FreeMan
    Commented Jun 22, 2020 at 13:17
  • It's on the main level, but we do have a finished basement so there's a finished ceiling below it. Not a bad idea to tear into it. Thank you for the suggestion! Commented Jun 22, 2020 at 14:18

1 Answer 1


Looks like grease. Check the door hinges and latch for dripping from over-lubrication.

Does not look like mold, and mold doesn't usually occur on top of carpet like that anyway.

  • It could definitely be grease, now that you mention it. We do have a grill and smoker outside on the patio. Commented Jun 22, 2020 at 14:19

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