Hot water heater valves are available at Ace Hardware and Home Depot. Both stores have a variety of valves, including gas valves, drain valves, and temperature and pressure relief valves.
The pressure relief valve on a hot water heater acts as a safety device by opening and discharging any excess pressure in the tank. Without a properly working pressure relief valve, a hot water heater may build up too much pressure and explode. A homeowner can check the effectiveness of the valve by turning off the electricity or gas powering the machine and shutting off the cold water into the heater. Then the homeowner should put a bucket under the valve and pull the lever. If the valve is working properly, it releases air and water.