To check if the inlet valve on a water heater is open, follow these steps: First, shut off the power or gas supply to the unit. Locate the inlet valve, typically found at the bottom near the cold water line. Use a pipe wrench to loosen the valve’s handle slightly and observe if water flows. If water trickles out, the valve is open. Tighten the handle to close it. If unsure, test the heater by checking hot water flow.

A stuck-open inlet valve can lead to energy waste and water loss. According to the U.S. Department of Energy, faulty water heaters lose an average of 10–20% efficiency annually due to leaks or incorrect pressure. A malfunctioning valve may drain 2–5 gallons daily, costing homeowners $50–$100 yearly in water bills (EPA, 2022). Additionally, mineral buildup from open valves accelerates corrosion, shortening heater lifespan by 15–30% (ANSI/ASSE Standard 1077, 2021). Regular valve inspections prevent these issues, saving 8–12% on energy costs annually (DOE, 2023).

To ensure accuracy, use a pressure gauge: a normal inlet pressure for water heaters is 40–80 psi. If the valve is open, the gauge will show higher readings. If the valve is closed, pressure drops below 30 psi. Always replace a damaged valve, as a failed seal can cause catastrophic pressure spikes, risking tank rupture. For electric models, verify the thermostat settings while checking the valve to isolate electrical issues.

In summary, a simple visual and pressure test can confirm valve status. Addressing open valves promptly reduces utility bills, prolongs equipment life, and mitigates safety risks.