To open a water heater's water valve, first shut off the power or gas supply to prevent accidents. Locate the valve near the tank's inlet pipes, typically on the left or right side. Use a adjustable wrench to loosen the valve counterclockwise until water flows. If the valve is stuck, apply penetrating oil and wait 10 minutes before retrying. After opening, drain a few gallons of water from the tank to flush sediment. Test the flow by checking the hot water supply.

Proper valve operation is critical to ensure safe and efficient water heater function. A stuck or closed valve can lead to pressure buildup, pipe damage, or even explosions, as reported by the U.S. Consumer Product Safety Commission (CPSC), which estimates 4,000 annual water heater-related injuries. Sediment buildup, which occurs when water minerals settle at the tank's bottom, can reduce efficiency by 15% and increase corrosion risks, according to the Department of Energy. Opening the valve annually removes sediment, prolonging the heater's lifespan by up to 6 years. Additionally, CPSC data shows that 60% of water heater failures stem from unaddressed maintenance issues, including blocked valves. By following these steps, homeowners can mitigate these risks and maintain consistent hot water access. Always prioritize safety by disconnecting power/gas before working and consulting a professional if uncertain.