In our bathroom tub, I can hear sound of running water with both the hot and cold water faucets turned off. It is a faint kind of a sound. Water to the toilet, which sits next to the tub, is turned off. I do not see water on the floor in the adjoining bedroom or any evidence of mold/mildew in the tub area or on the wall in the adjoining bedroom. The tub is on an outside wall. However, what I have noticed is the ground on the exterior of the house, on the other side of the wall where the tub sits, is moist. There are two AC units just on the outside of where the tub sits in the house. My sprinkler system has not been run for the past two weeks. And the Dort is dry when you get a couple of feet away from where the tub sits on the inside.

I tried to turn off the supply line to the water heater, but it does not easily turn and I do not want to force it (which might cause additional problems).

Any ideas if it is 1)a leaky hot/cold faucet or 2) a leak in the hot or cold supply line or something else?

90% of the times,or more, it is due to a broken hot water line under the concrete floor.

do you have city water with a water meter?

if so, check to see if the meter is turning.

Thanks for responding. So, I guess since it is under the concrete somewhere that is why there is no direct evidence of water in the adjacent bedroom?

>So, I guess since it is under the concrete somewhere that is why there is no direct evidence of water in the adjacent bedroom?

Yes. Sometimes a good (expensive) moisture meter will detect higher moisture through the concrete, but that depends on many factors.

You have done good detective work so far. Take it a bit further.

1. FOllowing up on Packy's advice, check your water meter. If the indicator is not turning/blinking/whatever, you do not have a leak on your side of the meter. But it is likely that you do.

2. Following up on HJ's advice, turn off the water to the water heater. If the noise goes away, he was correct (and it is likely that he is correct).

assuming the valve works properly and there are no faucets that allow crossover, which would negate the shutoff valve.