Causes: Worn out valves, seats and gaskets are common culprits. "Turning faucets on and off over the years wears these parts out," Hogan says. A faucet valve cartridge can also be to blame.

Another common reason for a leaking shower faucet is a deteriorating diverter valve. The diverter valve is a crucial component that directs water flow between the bathtub and the showerhead.

Leaky faucet? Running toilet? High water bill? Inthe United States, more than 1 trillion gallons of water is wasted yearly ...