On Friday, March 6, 2015 at 10:32:14 PM UTC-6, wrote:
We managed to dump about a half gallon of water on a carpet floor today.
It's just water so it's not gonna stain or anything, but the carpet is
fairly thick and has foam padding under it. My main concern is that it
dont swell the particle board floor under it. The wet spot is about one
sq. ft in size.

I dont have a wet-dry shop vac, or I would have used that. I laid dry
towels on it and stepped them into the spot. Then used more towels and
repeated a few more times.

Since then I have been using a heat gun on the spot. moving it quickly
so I dont burn the carpet. It's partly dry at the surface but I can
tell the padding is still wet.

Just thought I'd post this to see if anyone has other tips...

(No, I'm not gonna remove the carpet).

Thanks

The problem is mostly with the padding, which will be the last to dry. Your Shop Vac may work for water if the inside pipe deflects away from the motor. Remove any cloth or paper filter first. Google the model and see what the mfr. says. You should hope to get the padding dry within 3 days before mold and mildew set in. You may also have a stain from the spill; although only clean water, it will wick up soil from the subsurface as it dries. It may also leave a white outline from mineral deposits if you have hard water. To avoid wicking of soil you can put down a thick layer of white towels and put a weight on it; then the soil will wick into the towels. The cleaner your carpet the less the problem with wicking.

In the meantime keep applying dry towels and standing on them until no more water comes up.