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Install & Replace

Pressue saftey valve on Hot water heater

I need to know how to replace the pressure saftey valve on my hot water heater. It is leaking out the drain after I flushed the tank. Is this an easy fix or should I just replace the water heater. it was replaced in 03 and works fine.

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Posted 2011-01-18T18:29:30+0000  by RHElias RHElias

Hello RHElias and welcome to the Home Depot Community!


Compared to replacing the water heater, just replacing the valve should be much easier.  The hardest part will be getting enough torque on the valve to unscrew it.  An 18” or 24” pipe wrench should do it.  In any event using a “cheater” pipe on the end of the wrench will work if needed.


While it’s possible that the valve has just gone bad over time, if you tested it when you drained the tank then there might be a bit of sediment caught between the valve and seat.  Try a quick flush into a bucket and see if it stops leaking.  If that does not fix it here’s what you need to do:


Buy a new valve, Teflon tape or pipe dope and a new overflow pipe.  Home Depot stocks them:


Turn off the breaker to an electric tank or turn the control knob on a gas tank to “pilot”.

Turn off the cold water supply to the tank.

Open the hot water side of a faucet in the home.

Drain the tank for a couple of minutes to get the water level below the pressure valve.  Don’t completely drain it.  The weight of the water left in the tank will help keep it from moving when you apply torque to the old valve.

Close the faucet you used to vent the system.

Remove the old overflow tube, and then remove the valve.

Wrap tape or apply pipe dope around the threads of the new valve and screw it into the water heater.

Torque it into place.  A “cheater” is not needed for this.

Either re-use the old overflow pipe or install the new one.  The pipe needs to be at least 6” off the floor and cannot have threads on the outlet side.  You never should be able to cap it off.

Turn the cold supply valve back on.  Open that faucet again slowly to refill the tank and vent the air out of the pipes.

Check for leaks.

Turn on the power/gas and fire it up!

Check for leaks.  Done!


I hope this helps,


Posted 2011-01-18T20:08:26+0000  by Chris_HD_CHI
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