How To Replace A Pressure Relief Valve On A Water Heater

If your water heater is hissing or dripping, it may be time to replace the pressure relief valve. This job is easy to do yourself and only takes a few minutes. However, you will need a few tools, including a wrench and a screwdriver. You may also need a new valve if the old one is rusted. This article will show you how to replace a pressure relief valve on a water heater.

Shut off the power to the water heater

Shut off the power to the water heater. This means turning off the breaker for your electric-powered water heater and cutting off gas sources if you have natural gas or propane-powered appliance. You also need to shut off any electricity coming into contact with the hot water tank by shutting down any breakers and turning off any fuses or circuit breakers.

Turn off the cold water supply

Before replacing the pressure relief valve on your water heater, you must ensure that the water supply is turned off at all sources:

  1. Shut off the cold water supply at the main shutoff valve in your home.
  2. Turn off the cold water supply to your house or building.
  3. Shut off separate valves (if applicable) leading into each fixture or appliance in your house or building, such as under-sink faucets and washing machines.

Open a hot water faucet

  • Open a hot water faucet. This allows air to enter the plumbing lines and prevent any explosions. Do not open a cold water faucet.
  • If you have a gas water heater, do not open any faucets because of the high pressure in the system caused by heating and cooling elements that can cause dangerous amounts of pressure to build up in your pipes if they are opened without allowing them to cool down first.
  • If you have a tankless water heater, do not open any faucets after draining out any remaining water because of possible damage to internal components from atmospheric pressure changes.

Drain the tank

Drain the hot water tank. If you have an electric water heater, turn off the power to the unit. Next, drain the hot water tank through the drain pipe located near the bottom of the tank. If you have a gas water heater, remove the top cap and allow the water to flow out of the tank.

Remove the discharge tube and valve

Now that you have the pressure relief valve disassembled, it’s time to remove the discharge tube and valve.

The discharge tube is a pipe that connects your water heater’s pressure relief valve to its drain line. The connection between them is made with a compression fitting; no fasteners are holding it on—you simply need to unscrew it with a pipe wrench.

Once you’ve removed this fitting (there may be a short piece of copper pipe still attached), pull off any insulation or protective jacketing around your existing discharge line and remove any debris inside of it before pulling it away from the heater’s drain connection point.

Clean the threads in the water heater

Next, you need to clean the threads on your water heater. This is because if you don’t clean them, it could be hard for you to tighten the new valve in place.

To clean the threads, use a brush, soapy water, or vinegar. Make sure they are nice and clean before installing your new pressure relief valve.

Install the new valve and tube assembly

To install the new valve and tube assembly, use pipe dope on the threads of the new pressure relief valve. Make sure that you install it in the same direction as your old one.

  • Use a wrench to tighten down the new pressure relief valve. Be sure to check for leaks around the base of where you installed it, as well as anywhere else along your water heater’s pipes.

Test the new T&P valve

Test the new T&P valve. First, turn the water heater on for at least 15 minutes, then check the following:

  • The temperature of water (if hot) or pressure (if cold). It should be a consistent temperature or pressure in each fixture throughout your home.
  • Flow and force of spray come from showerheads, faucets, and toilets. There shouldn’t be any leaks, drips, or reduced flow. If there are issues with these fixtures, shut off the main water supply to your home and call a plumber to diagnose them further. If everything checks out okay after testing your T&P valve and drain valve using these steps, you’re ready to close things up.

Frequently Asked Questions [FAQs]

1. Is Pressure relief valves important to keep your home safe?

A pressure relief valve is an important component of your water heater. Its job is to protect you and your home from dangerous situations such as scalding, water damage, and potential bursting. While these valves are required by code, they’re also easy to replace at a low cost.

2. What is a pressure relief valve?

A pressure relief valve is a device installed on a water heater to help protect it from overpressurization.

3. How do I replace a pressure relief valve on a water heater?

If your water heater’s pressure relief valve leaks, it must be replaced. Follow these steps to replace a pressure relief valve on a water heater:

1. Turn off the power to the water heater.

2. Drain the water from the tank.

3. Remove the old valve by unscrewing it from the tank.

4. Install the new valve by screwing it into place.

5. Turn on the power to the water heater and open a hot water faucet to allow air into the tank as it fills with water.

4. What are the risks of not replacing a pressure relief valve on a water heater?

If your pressure relief valve is not working properly, your water heater could explode. This could cause serious injury or even death. Therefore, it is important to have a qualified technician replace your pressure relief valve if it is not working properly.


If you’re experiencing a leak or other issues with your water heater, it’s important to have it replaced as soon as possible. It is dangerous to leave the old one in place, but it will likely continue to cause problems until you get it fixed.