How to Repair a Leaking Water Heater Pressure Relief Valve

Ask Danny, Plumbing, Repairs and Installation by Danny Lipford

I just flushed my hot water heater as you mentioned and now the pressure relief valve is leaking. Is this something I can replace on my own, or should I call a plumber? -Leighton

Hi Leighton,
Pressure relief valves sometime develop a drip when opened for the first time in years. Try opening and closing it a few times to see if it will seat itself. If you have a large leak or the drip doesn’t stop on its own in a day or two, the valve will need to be replaced. Whether you can replace it yourself will depend on your skill level, but as far as plumbing repairs go, it’s not that difficult. If you do try to fix it, here are the basic steps involved:

  • First, turn off the gas to the water heater, or flip the breaker if it’s electric.
  • Close the cold water cut-off valve going into the water heater.
  • Open the valve at the bottom and the pressure relief valve for a minute to drain a little water out of the tank and relieve the pressure.
  • Remove the overflow pipe from the pressure relief valve. If it’s been glued or soldered in place, it may have to be cut off.
  • Use a pipe wrench to unscrew the old pressure relief valve.
  • Wrap Teflon tape around the threads of the new valve, and screw it in until tight, orienting the overflow pipe opening away from the tank.
  • Reattach the relief valve drain pipe using Teflon tape on the threads. If you have to replace the drain pipe, use pipe (and glue) that is rated for hot water (such as CPVC rather than PVC).
  • Open the cold water cut-off and check for leaks around the relief valve.

Good luck with your project,

Danny

Further Information:

Water Heater Maintenance

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8 Comments on “How to Repair a Leaking Water Heater Pressure Relief Valve”

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  1. Randy Says:
    September 16th, 2008 at 01:41

    Hello Danny,

    I have did everythings you said but my valve still run water when I cut it back on. Even if the valve is cold it still run and have a lot of pressure. What should I do.

    Thanks.

  2. Pat Dover Says:
    January 5th, 2009 at 18:46

    Maybe from now recommend turning the main supply line off. Today we changed a relief valve on a heater in an attic. The plumbing had been crossed. The shutoff was on the cold inlet side of the heater but the cold water was coming in to the hot side. Dip tube changed and c and h crossed. Not good is a understatement. Just an idea but thats how I will approach it from now on. Turn off main. Real fun going behind a sorry plumber

  3. Pam henderson Says:
    April 14th, 2009 at 14:24

    I had a leak from pressure valve which finally just blew across room. I replaced valve but when I turned the main water valve back on only upstairs water runs. I didnt turn anything else off but the gas and delmarva told me how to do that. for three days I have no water on 1st floor, but have water in basement and second floor. Help!

  4. Jennifer Says:
    January 14th, 2010 at 12:49

    I have attempted to change the TPR valve b/c it has a slow leak, I have followed all the steps, however I am unable to remove(unscrew) the TPR valve. I had a 250lb man use his weight and a pipe wrench to try and remove the valve in order to replace it with a new one. A cheater won’t work b/c that 250lb man bent the relief valve drain pipe threads. Can I try to use WD-40 or some other trick of the trade to get the TPR valve off w/o damaging anything?

  5. Eduardo Says:
    April 23rd, 2010 at 11:00

    Replace my tpr, now I have no hot water pressure.

  6. Official Comment:

    Ben Erickson Says:
    April 24th, 2010 at 08:57

    Hi Eduardo,
    Unless it’s leaking substantially, replacing your temperature pressure relief valve shouldn’t have an effect on water pressure.

  7. MichelleC Says:
    May 26th, 2010 at 02:16

    I replaced my old hot water tank about 2 years ago because no one I called could not get the overflow pipe to stop leaking, even after replacing the valve twice! Within 2 weeks of installing the new one…it started leaking too. As I forestated, that was 2 years ago…and it is still leaking. I am really frustrated about how to stop this leaking. The valve has been replaced on this once, and as of today, a plumber, who is a friend of ours lowered the pressure…?? and within an hour after he left, the leaking started again! What else can I do?? Thank you.

  8. Craig T Says:
    May 28th, 2010 at 15:12

    Michelle:
    I had the same problem. Mine was cured when I installed an expansion tank on the cold water line running into the water heater.

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