I had a plumber replace my T & P valve on a 08' 50gal. American water heater. It kept discharging water practically every other day. He replaced the T & P valve and water started relieving again 2 hours after the plumber left. Not much, but enough to indicate a problem still exists. What other troubleshooting solution is there, short of replacing the water heater. Should I just replace my water heater?

  • Is this a gas or an electric heater? And what is its model number? Mar 1, 2015 at 4:05
  • See if this might apply to your situation, and/or describe your plumbing in more detail. If you just asked the plumber to replace the T&P valve, I suppose he gets a pass, but you could certainly call and mention that it's leaking 2-hours later. If you asked the plumber to fix the leak, he should have seen this if it applies, and deal with it in any case if it leaks right after he worked on it. diy.stackexchange.com/questions/61103/…
    – Ecnerwal
    Mar 1, 2015 at 4:06
  • Is there large use of hot water on an "every other day" basis that would track with the releases? If it's an expansion issue, I'd expect a day of heavy hot water use to be followed by water release when the large amount of cold water (that refiled the heater as hot was drawn out) was heated up, and nothing was using water in the house.
    – Ecnerwal
    Mar 1, 2015 at 4:21

1 Answer 1


There are four reasons a temperature and pressure valve will release water.

The valve was physically opened

If you; or somebody else, opens the valve, it will obviously release water.

Since you didn't mention holding the valve open, I'll assume that's not the problem.

Bad valve

If the valve is bad, or junk is stuck in it, it can cause water to be released.

Since a plumber just replaced it, I'd guess this is not the problem either.

Pressure is too high

When water is heated, it expands. This expanding water increases the pressure in the closed plumbing system. If the pressure gets to high, the valve will open to release some of the pressure.

You'll have to put a gauge on the system to determine if this is the problem.

Temperature too high

If the temperature of the water in the tank gets too hot, the valve will open to release some of the overheated water.

Again, you'll have to put a gauge on the tank to find out if this is the problem.

Since it sounds like it's only a small about of water, I'd lean towards high pressure.

To verify this, you'll want to connect a pressure gauge that can remember the maximum reading to the system. Then use the system as normal, checking the gauge from time to time.

Once you determine tha actual cause, then you can start looking for a cure.

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