To fix a leaking inlet water pipe valve on a water heater, first shut off the water supply and power to the heater. Use a wrench to loosen and remove the hexagonal nut connecting the inlet pipe to the valve. Inspect the valve for damage; if the seat is corroded or the valve stem is worn, replace it with a new one. Apply pipe thread sealant to the threads of the new valve before tightening it. Reconnect the pipe and test for leaks by slowly refilling the tank. If the leak persists, check for additional damage to the pipe or tank.

A leaking inlet valve can cause significant water damage, increase energy costs, and reduce the heater’s efficiency. According to the U.S. Environmental Protection Agency (EPA), non-functional water heaters waste an average of 4,000 gallons of water annually due to leaks, contributing to higher utility bills and environmental impact. A faulty valve also strains the heating system, leading to frequent repairs or replacements. The American Water Works Association (AWWA) estimates that 12% of household water damage incidents stem from plumbing leaks, with repair costs averaging $5,000 per incident. Regular maintenance, including valve inspections and replacements, is critical to preventing these issues. Replacing a damaged valve promptly ensures proper water flow, maintains pressure balance, and prolongs the heater’s lifespan, aligning with DIY repair guidelines from the Department of Energy (DOE).