A dripping faucet when turned off is typically caused by a worn-out or damaged washer, O-ring, or valve seat within the faucet assembly. These components can deteriorate over time due to regular use, resulting in leaks. Faucet repair involves disassembling the faucet, inspecting these parts, and replacing any that are worn or damaged. A professional plumber from Warner Super Service, Inc can assess the issue and perform the necessary repairs to stop the dripping and conserve water.