I can hear running water in my wall. I turned off all of the sinks and toilets in the house, and I cannot find sitting water anywhere in the house or outside. I was told they have a flexible hose that can go inside the copper pipe. Does the flexible hose work?

Try turning off the water to the house, what do you hear? Open up the cleanout and see if water is running through.

I did turn off the water to the house and I stopped hearing the water. I turned the water back on and I heard it again. Also, I turned off the hot water and I stilled heard the water.

Hi Tpkelly

Check your toilet tank and see if water is flowing over the pipe in the center of the toilet tank. If water is overflowing the tube in the center of the tank then, most likely, you need a new toilet fill valve.

If that fails to show a leaker then drip about 20 drops of food coloring into the toilet tank and go away for 5 minutes...when you return, if you see colored water in the toilet BOWL then you need a new toilet flapper or flush valve.

Post back with results, OK?

Mark

I was wondering about that but took the assumption that, as stated, "all toilets were turned off".

That was the first thing I thought of. Both toilets were turned off. I will replace the the stop tomorrow because it is old. I will make sure the toilet is shut off by flushing it, and i will look to see if the tank hose will fill up the tank. I do live in a hard clay area, and maybe that is keeping the water from coming out from under the house.

You are on a slab I gather. Look for damp or wet spots in carpet. It's in the CW side if you turned off the HW heater and still heard the noise. Finding a leak in a slab can be problematic, you may need to hire American Leak Detection or someone like that.