My mother bought a home in North Carolina and built in 1994. She is noticing a large area 24" of wet carpet(wall to wall). The house was built on a slab. She is 75yrs old and is not sure who to call first or how serious this could be. Her hot water heater is gas and there are no signs of leakage near the water heater.She has put towels to absorb the water but it is not helping. What is the likely problem?