Did you know that there is one thing that keeps your water heater from becoming a rocket? It's called a T & P valve or TPRV (Temperature Pressure Relief Valve). This is a small brass device that is typically located on the top of the water heater or on the side of the unit near the top. When functioning properly this valve will prevent your water heater from rupturing, or in some cases, completely exploding if the temperature or pressure in the tank gets too high. In some cases, water heaters have been known to shoot like a rocket through a wall or roof.