Can't figure out where water is coming from.

I found a wet spot (about 1 ft x 4 ft) along the wall in the master bedroom. The carpet and padding is soaked.

We had pex piping put in about 3 yrs ago (because of a slab leak) in that wall.

I checked the water meter and noted the number and where the dial was pointing at. Checked back about a half hour later, and there wasn't any change to indicate a major leak. Can a subtle weak not be detected through this method?






There are 2 toilets near that wet spot. There's a toilet directly on the other side of that wall in the guest bathroom. Also, behind the wall with the door, sits the master bedroom toilet (about a foot away from the wall). Can a leaky wax seal between the toilet and flange cause water to seep under the tile into the adjacent room? We replaced the wax seal for the toilet in the master , just in case, but before I do the toilet in the guest bathroom, I want to know if this could be the cause before I go through the trouble. Toilet works fine and I can't tell if there's a leak around the base because it was caulked off, and even if there was a leak, I wouldn't be sure if water would even make it to the wall and underneath to the carpet on the other side.

There's also a shower in the master. When I put my ear up to the tile wall, I hear a faint sound like wind or running water. Can a leak from that shower section make its way over to the wall (with the door) and into the other room? Even though the meter isn't moving to indicate a leak? The wet spot is directly behind the wall next to the door.

Water takes the path of least resistance, so the source could be a ways from where you're seeing it. If it is a really slow leak, it may take awhile before you notice the water meter dial move. If the house is vacant during the day, you might check before you leave, then when you get back after work.

Was the sound in the wall while the shower was on, or when everything was off? From the picture of the tub spout, it appears that that valve and spout may be fairly old...if that spout passes code, the outlet is really close to the tub rim - it needs to be above it.

The toilet wax ring could be leaking, particularly if the bathroom floor has layers that the water could be running between. It could also be the tub caulk, drain, or supply leaking.
If you have had heavy rains or snowmelt, the water could be coming in from outside.