We have noticed a small wet spot on our rug, which happens to be next to a ceramic tile, near our entryway. The wet spot is about 3" from a closet, and on the other side of the back of the closet wall is our laundry room, with washer and dryer.
The grout on the tile next to the wet spot is darkened for about 3", probably from becoming wet from underneath? There is absolutely no standing water and the wetness is only in a small approximately 3" diameter area.
Does piping run in or under the cement slab? If so, and if a pipe is under the wet spot, how would a leak occur and how would it go UP into our carpeting instead of down into the ground/concrete?
Any help would be appreciated.

Good morning Jane,

Ah! The dreaded "wetspot". In my area all our homes are built on slabs and this is a problem I've faced maney times. What's happened here is that one of your underground pipes, copper or galvanized, depending on the age of the house, has sprung a leak. And the worst part is that the leak might not be under the wetspot. Water, like electricity, will seek the path of least resistance. The leak might be some distance away from the spot where it initially appears. The reason the water has surfaced is that it's saturated the surrounding soil and has nowhere else to go.
When that happens we call in a "leak detection" company like Sleuth that specializes in locating underslab leaks. They have sensitive listening devices the will pinpoint the leak. They will then jackhammer up the floor, dig down, bare the leak and bag the dirt. Then the plumber comes in, repairs the leak, fills the hole and patches the cement slab. You may double check by shutting off every fixture in the house so no water's running. Now if you're on a meter look at the little pointer on the face of the gauge. If it's moving 5then you have a leak. If on a pump, shut the pump off and watch the pressure gauge, if it falls back rapidly then you hane a underslab leak. Sorry I couldn't be more upbeat. Good luck, Tom