If you are concerned that your water pressure is too high it is recommended that you contact a professional licensed plumber to check your pressure, or you can do so by purchasing a pressure gauge that can be attached to any outside water faucet. You may install a pressure regulator on your water service line if you deem necessary. Installing a pressure regulator will create a “closed system”. 


    Thermal expansion is the term used to describe the circumstance of water expanding in volume as it is heated. All water heaters can suffer the effects of thermal expansion.  As the cold water is heated the overall water volume and pressure increases. For safety, this increased pressure must be relieved in some way. Before major controls were placed upon water suppliers, it was possible for excess water pressure build-up in a water heater to flow back into the public water supply. This created a simple and efficient system for removing excess pressure in water heaters.
    However when a check valve, pressure reducing valve or backflow preventer is installed a “closed system” is created. A method of controlling thermal expansion and relieving pressure build-up must be installed. The temperature and pressure relief valve (T&P) on the water heater opens when a sufficient level of pressure is reached. This allows the heated water to spill out of the system relieving the pressure and lowering the volume. T&P valves are designed for emergency situations. Its parts are not manufactured for daily use.
    Sometimes, damage can occur before the safety relief valve has a chance to relieve the water heater of excess pressure. Fast acting solenoid valves on appliances (washing machines, dish washers) and some plumbing fixtures can create an instantaneous pressure spike that exceed the rating of the water heater tank. Excess pressure can distort the tank head, the tank base, and the hot and cold water lines.
    Installing a properly sized and charged thermal expansion tank in a water heating system is the recommended way to eliminate the problems associated with increased volume and pressure in a closed or restricted plumbing system.
Consult a professional licensed plumber for more information.