These spots have come up suddenly. They are multiplying daily. They appear clear, but are a little sticky to touch. No pets, no source of water, nothing falling from ceiling or walls - so it much be coming up through the floor somehow. I hate to take up the wall to wall carpet to investigate, but that may be the only course of action.

Termite infestation would not likely leave the symptom that you describe.

Are you able to check out the floor from below (via basement or crawlspace)?

Are you positive that it's not spills of some sort?

If you are not able to figure it out, then you can pull the carpet back to check out the floor beneath it... and then a carpet installer with a kicker can put it back for pretty cheap.

Also double check the wall(s) closest to the spots. Do you see any evidence of moisture there?

Thank you Rick for your reply. We are unable to get easily into the crawl space, as the area has been sealed off with insulation by the last owner. These spots have sprung up (in various places in the same room) overnight. In spite of cleaning they keep coming back in different places (same room). It is most perplexing! I was thinking honey bees, but there is no sound or visible sign of them. The problem has been visible now for about a week. The weather has been wet, so it is remotely possible that moisture is coming up through the crawl space, but this wouldn't explain the stickiness.

Could you imagine a nest of something (squirrels, rodents) making an effect like this?

I am so thankful for your opinion about termites not doing this. I know they can come on suddenly, and it is all I've worried about since seeing these spots.

Getting into that crawlspace is mandatory.

From there you should be able to see a lot more than you can see from above.

I cannot think of any rodent or insect that could be infesting the area that would cause wet spots to move "up" through the floor and appear in the carpet.

Moisture in the crawlspace, generally speaking, would not work its way UP. Moisture moves down.

1. Get into that crawlspace and inspect it well... looking closely at the floor below the room where you are seeing the wet spots on the carpet.

2. If that does not show you what the problem is, then you'll need to pull back the carpet and padding in the room above... and look close. Be careful to not damage the carpet when pulling it up, so that a carpet installer can easily stretch it out again, without having to repair it.