The T&P Relief Valve – A Little Piece with a Huge Job
Temperature and Pressure Relief Valve

16 Oct The T&P Relief Valve – A Little Piece with a Huge Job

It may not be the biggest piece of equipment in your home, but the temperature and pressure (T&P) relief valve provides protection from an overheating water heater. In a recent visit to a Roseville client, one of our plumbing pros found a malfunctioning T&P Valve that could have jeopardized the safety of the family living there. This particular valve had mineral build-up on the valve seat due to a significant period of discharge. This meant that there had been a problem with the water heater for quite some time before our tech caught it during a maintenance call for another issue.

A T&P valve has one job, to release pressure by venting hot gases and liquid from the top of the tank if they reach dangerous levels. These levels are temperatures above 210 degrees or pressures of over 150 psi per gallon. The T&P Valve prevents pressure from building up in the system that could otherwise turn your water heater into a bomb filled with scalding hot water.

The T&P valve is a secondary safety measure to prevent a major catastrophe. When it is working correctly, a leaking T&P valve is an indication that there is a problem in your water heater. It could be any of the following:

  • Your water heater temperature is set too high
  • You have a defective thermostat
  • You have a faulty heating element
  • You have a compromised T&P Valve


If these problems aren’t fixed, your water heater will start to undergo thermal expansion. Most tanks will expand about ½ gallon during typical heating, more than that can start to compromise the integrity of the seal on the stainless steel tank. If the expansion continues, the tank will eventually burst sending boiling water spraying in your utility room or garage.

Exploding Water Heater Aftermath

It is extremely important that you have your T&P valve checked annually to make sure it is in proper working order. This is a standard part of our Premier Plumbing maintenance service on all water heaters. Call us today to schedule one today and make sure your family is safe from this potential ticking time bomb.

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