A single-handle faucet uses a plastic, metal, or rubber valve cartridge system to control water flow. When a single-handle bathtub faucet leaks, the valve cartridge or its rubber o-rings may be worn out or corroded. Valve cartridges must be repla… stop the constant faucet drip soundâ€at least temporarily, until you're able to fix it for good:

Stop the bathtub drain and fill the tub with several inches of water. Squirt in a generous amount of dish soap and gentl…