The information on this web site is supplemental to the printed instructions that came with your water heater. To reduce the risk of property damage, serious injury or death, read and follow all labels on the water heater and the safety instructions in the printed owner's manual.
Water pressure gauge a lazy hand
Pressure reducing valve
Thermal expansion tank
Drips coming from the T&P discharge pipe often mean the home's water pressure is too high.
DANGER! Never cap or plug the T&P discharge pipe.
High water pressure can damage the water heater (causing leaks). High water pressure can also damage your washing machine, dishwasher and ice maker.
High water pressure is one of the main reasons water heaters leak prematurely.
Plumbing codes require that your home's water pressure be 80 pounds per square inch (psi) or less. Most experts recommend 50-60 psi.
If your old water heater leaked prematurely, check your home's water pressure with a pressure gauge (available at hardware stores and home centers for a few dollars). Measure the water pressure over a 24-hour period. (Water pressures are highest at night.)
If your home's water pressure is above 80 psi, install a Pressure Reducing Valve.
Pressure Reducing Valves are usually set at 50 psi at the factory. However, they are adjustable. Adjust the valve so that your home's water pressure is 50 psi.
In many cases, a Thermal Expansion Tank is often needed to stop drips from the T&P valve.
Replacing the T&P valve almost never stops the drips because T&P valves rarely fail and almost all drips from the T&P valve are due to high water pressure and thermal expansion.
See Maintenance section for more information about Pressure Reducing Valves and Thermal Expansion Tanks.