Recently installed a new electric water heater with an expansion tank. Water coming into the house is 52 psi, the line that runs to outside faucet is the same pressure but the faucet in the sink after my water heater is at 140 psi and the pressure release valve has a small constant drain and I have am at a lost as to what is causing this.

  • How are you measuring this pressure? If you vent the pressure release valve (into a bucket) does the excess pressure at least temporarily go away? Apr 19, 2016 at 22:14

1 Answer 1


Sounds like you expansion tank is failed or not pressurized properly. I suggest draining the expansion tank and checking the pressure. If you get any water out of the air valve, your tank has failed.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.