To fix a leaking water heater inlet valve top, first shut off the water supply and power to the unit. Drain the tank to remove water pressure. Remove the inlet valve using a wrench, inspect for worn O-rings, gaskets, or debris. Replace damaged components with manufacturer-approved parts. Reassemble the valve, refill the tank, and test for leaks. If the issue persists, consider professional repair or replacement.

The leakage occurs primarily due to worn seals or mineral buildup. Over time, temperature fluctuations and water pressure strain the O-rings and gaskets, causing cracks or failures. Hard water deposits, common in regions with high calcium or magnesium levels, accelerate scaling and blockages. A 2021 study by the U.S. Environmental Protection Agency (EPA) found that 15-30% of water heater failures involve inlet valve issues, often linked to mineral scaling. The average lifespan of an inlet valve is 5-10 years, but improper maintenance or hard water can reduce this. Replacing seals and addressing water hardness (via filters or water softeners) can prevent recurrence. Industry data from the National Association of Home Builders (NAHB) suggests that 40% of residential water heater repairs involve valve-related problems, emphasizing proactive maintenance to avoid costly replacements.