Plumbing, Water Heaters

Water Heater Leaking From Relief Valve

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Hubert Miles

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You’ve owned a water heater for many years, probably way past its expected lifespan. It hasn’t exploded, neither does it look like it might. If you have been doing your regular heater maintenance, congratulations – you’ve done great. You have one small but vital component to thank for that. Your relief valve has performed per expectations. 

A water heater’s pressure relief valve releases pressure from the tank to keep everything working right. A faulty pressure relief valve puts your heater at risk of exploding. To keep the relief valve in good working order, ensure it has a tight seal, is not cross-threaded, the tank is sediment-free.

Did you know you can fix a leaking relief valve? We’ll show you how to keep your drain valve in top shape. 

How Do I Know If My Water Heater Relief Valve Is Bad?

Excessive Persistent Noise

Your water heater occasionally makes weird noises due to what’s in the tank. However, If you notice a persistent rattling or high-pitched whistle, it might be a sign of pressure trying to escape the heater. These noises over time mean the valve isn’t opening and closing as it should. That also means it is releasing less pressure. It could be putting your water heater at risk of explosion

Sediments in the Water From Your Outlets

Dirt or debris in your water hot water outlets is a sign that your valve is overdue for replacement, and your heater has been taking continuous internal damage. Excess pressure tends to wreck the tank’s internal lining. The debris accumulates and disintegrates in the tank. If the damage continues and the sediment isn’t flushed, it shows up in your outlet taps. 

This is a risky stage of the heater’s breakdown. At this point, you might need a professional plumber to tell you if it’s up for repair or replacement. 

Continuous Leaking

Sure, the water relief valve leaks. However, if it leaks after fixing or when it’s not under any pressure, you might have a bad valve. Continuous leaking could be from constant overheating or excess pressure and not enough release. Both are signs of a failing valve. Also, it can be a sign of a bad thermostat that cannot control heat. 

A loose relief valve cannot hold pressure. Therefore, it keeps leaking. 

Leaking From the Tank

Leaking from the tank should be a cause for alarm. It means your heater has taken so much damage from the pressure that the lining has become weak, and it’s breaking. The tank cannot drain water, and the pressure in it only makes the situation worse. 

At this point, your options are limited to just getting a heater replacement. However, on the off chance that you can still salvage your tank and you can repair the relief valve, you need to do it as soon as possible. 

How Do You Test a Water Relief Valve

leaky T&P Valve

The relief valve doesn’t always have a problem for it to leak. Extreme weather conditions such as super cold winters can make the valve not perform to its best potential. Other factors include rust, corrosion, and debris in the seal. These factors are why it is crucial to test if the relief valve works. Here are the steps in testing a water relief valve:

  1. Make sure you safely conduct any checks every time. The water in the heater will likely be hot most of the time. You can wait until it’s cold before checking the valve. Alternatively, have a licensed plumber check the valve during maintenance.
  1. For an electric heater, shut off the power from the main circuit breaker. Whether you decide to do it yourself or call a plumber, first turn off the power and the gas. Your heater probably has a dedicated shut-off switch. Turn the gas valve to ‘Pilot’ or ‘Off’ if you have a gas hot water tank. 
  1. Flip the lever open once to let off some pressure. Place a collection pail under the overflow drain pipe for the outflowing water. Now, flip the lever for about five seconds and close it. Repeat this a few times, noting if any water comes out from the overflow drainpipe. 

Checking if the relief valve is working is helpful for two things. It tells you whether the problem is with the valve or not.

  • It clears out sediment
  • If you notice a leak after checking the valve, it’s time to replace the valve. 

How Do You Stop a Relief Valve From Leaking?

Right about this point, you’re probably tired of fixing the leak. The quickest fix would be to replace the valve and install an expansion tank to boot. However, there’s a faster fix that you might be overlooking. 

The relief valve is a spring-loaded contraption. If the spring is not seated correctly, it leaves space for water to drip. Fortunately, you can fix it before considering replacing the entire valve (the best option). 

Flipping and closing the lever on the relief valve firmly can reset the spring to its comfortable position. Usually, the seal and the gasket get misaligned because of long-term negligence. It gets corroded and leaves spaces for leaks. Flipping and closing the lever removes some of that corrosion. 

If the leak doesn’t stop, it’s time to replace the valve. Here are the steps to do so:

1. Drain the tank

Drain the tank to below the relief valve level. You can drain the entire tank. However, most tanks hold as much as 50 gallons in them. It would be wasteful to drain all the water in a tank to replace the relief valve. However, you can drain it if you’re also flushing the tank. 

2. Remove the discharge tube.

The discharge pipe extends to the ground. This tube is essential to the relief valve mechanism. It drains all the overflow when the tank drains itself. Without the tube, the pressure would make hot water splash out from the valve, posing the threat of serious injury to anyone close. 

3. Remove the old relief valve

Have the replacement valve close. A replacement valve costs about $20 in stores. Use a pipe wrench to unscrew the old faulty valve. Turn it anticlockwise to pry it open. Brush the inner area with a wire brush to remove any sediment and buildup in the inner part of the tank. 

4. Tape the new relief valve

Teflon tape or plumber tape is a vital part of the installation. It allows you to get a tight fit. Also, it makes the new installation smoother. Wrap the Teflon tape clockwise about six times. Leave about three threads of the new drain valve exposed. The exposed threads are your anchor. Screw it in place. 

Note: Each valve is inscribed with its temperature and pressure setting. Ensure you buy one that matches the previous valve’s setting. 

5. Turn the water on

Before you return the overflow pipe, turn your water back on from the cold inlet. Also, power back your gas. You’ll know the tank is full when the tap you left open starts letting water out with a steady flow. 

6. Test out the new valve

Flick the lever of the new valve open to release some of the initial pressure. Hold a bucket under the new valve. Hold the lever open for a few seconds, then release it. Make sure there are no leaks. Once you ensure there are no leaks, put the overflow pipe back on. 

Bonus Tip: Install an expansion tank

An expansion tank is a smaller tank that you can install above the heater. The expansion tank takes in some of the excess water from the thermal expansion in the main heater. With less water and less pressure in the main, there is less risk of the main heater getting damaged. 

You can install an expansion tank by welding it onto the main supply line of the water heater. 

How Often Should Pressure Relief Valves Be Replaced?

Your relief valve WILL wear out. However, you can stay ahead of the damage if you check its status once in a while. Surprisingly, you won’t need to check it that frequently. 

First, check once a year whether the relief valve is working. You can make it frequent if you live in an area with different conditions like hard water or too high water pressure. 

Regardless of whether you check the relief valve once or twice per year, you need to replace it. You should replace the pressure relief valve on your water heater every five years, even if it’s in okay shape. 


Your home is one bad valve away from heavy damage from a bad heater. It’s in your best interest to ensure your water heater doesn’t bring you such a loss. You can choose to check your water heater as part of your yearly home inspection, or you can hire a home inspector to run a full panel of checks for you. Either way, your house becomes the home you’ve always dreamed of it to be. 


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Hubert Miles

I've been conducting professional home inspections since 2002. I'm a licensed Home Inspector, Certified Professional Inspector (CPI), Certified Master Inspector (CMI), and FHA 203k Consultant. I started to help people better understand the home inspection process and answer questions about homeownership and home maintenance.
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