How to Replace a Leaking Water Heater Pressure Relief Valve

A water heater pressure relief valve is located on the side of a water heater and typically has a discharge tube connected to it to direct scalding hot water downwards.

Causes of a Leaking Water Heater Pressure Relief Valve

If the water heater pressure relief valve is dripping water, rather than gushing it, it could be caused by either a faulty TPR valve, or the water heater is beginning to exceed the rating limits of the water heater pressure relief valve.

Chances are if you have not been working on the water heater or plumbing it is just a faulty water heater pressure relief valve. Regardless of what caused the TPR to leak it needs to be fixed immediately.

Replacing Water Heater Pressure Relief Valves

Replacing water heater pressure relief valves is pretty straight forward, however you will need a large adjustable wrench or crescent wrench, a hose, bucket, and some plumbers tape.

Note: It is important to check the new water heater pressure relief valve after replacing the old one. Water heater pressure relief valve leaking after testing is a common phenomena, even in a newly installed one, so make sure to check that there  is no slow leak.

To replace a water heater pressure valve, first turn power off to the water heater and turn the cold water inlet supply line valve off.

After allowing the water heater to cool down awhile connect a garden hose up to the bottom drain valve and direct the other end of the garden hose outside of the home. Next, turn the drain valve on and allow some of the water to drain from the water heater. Also turn a hot water faucet on somewhere else in the house to help drain the water from the water heater. You do not need to empty the entire water heater tank, and as a matter of fact you should not.

Simply empty enough to get below the level of the water heater pressure relief valve. When you believe you have emptied enough water from the water heater tank, shut the drain valve and hot water faucet off.

Once you have drained off enough water from water heater, remove the discharge tube. Next, use the adjustable wrench to remove the water heater pressure relief valve.

Take the old water heater pressure relief valve to your local hardware store and find an equivalent replacement.

Make sure you buy a replacement water heater pressure relief valve that is rated for the same pressure and temperature as your old one. Prior to installing the new water heater pressure relief valve, wrap some plumbers tape around the threads of the valve. The plumbers tape will help to prevent any leaks around the threads.

Hand thread the new water heater pressure relief valve into the water heater and then tighten it snuggly with an adjustable wrench. Then reattach the discharge tube.

Finally, disconnect the garden hose, and turn on the cold water supply line valve, and power to the water heater. With any luck your leaky water heater pressure relief valve should be history. If the new one begins to leak then call in a plumber to see why the water heater is overheating and over-pressurizing.

Testing Water Heater Pressure Relief Valves

Hot water heater pressure relief valves have a lever on them so that you can test them to see if they are working properly. Have a bucket handy when pulling on this lever, and do not pull on it when the water inside the water heater is hot. Note that sometimes after testing a water heater pressure relief valve it may not entirely close and seal properly again. This is particularly true on older TPR valves, due to the fact that mineral content that may have collected on the internal parts of the valve prevent the water heater pressure relief valve from fully closing.

Water Heater Pressure Relief Valve Leaking after Testing

If a slow leak persists after testing your water heater pressure relief valve, you will have no choice but to replace it.