What is a TPR valve?
A temperature and pressure relief valve (TPR valve) is a safety device installed on water heaters that automatically discharges hot water when internal temperature or pressure exceeds safe limits.
A TPR valve, or temperature and pressure relief valve, sits on top of or on the side of a water heater tank and acts as a safety release. If the water inside the tank gets too hot (usually above 210 degrees Fahrenheit) or pressure builds up beyond the tank's design limits, the valve opens and lets hot water flow out through a discharge pipe. This prevents the tank from rupturing or exploding from dangerous internal conditions.
Every water heater tank in Aiken, SC must have a working TPR valve by code. The valve trips on two triggers. The temperature sensor inside the tank causes it to open if heat rises uncontrollably, often because the thermostat fails or the heating element runs constantly. The pressure sensor does the same if the internal pressure climbs too high, which can happen when cold water enters a sealed, heated tank and has nowhere to expand. Most residential water heater tanks operate at 40-80 pounds per square inch (PSI) of pressure, and the TPR valve typically opens at 150 PSI or above.
When a TPR valve leaks or drips regularly, it signals that something inside the tank is wrong, whether a bad thermostat, excess pressure, or sediment buildup. If you notice water pooling beneath your water heater or coming from the discharge pipe, have a plumber inspect it. Homeowners should also test the valve annually by lifting the handle slightly to hear or feel a short burst of water, which confirms it still functions. A faulty or missing TPR valve is a genuine safety hazard and a code violation. If you need inspection or replacement, contact a local water heater provider in your area.