We have a brand new Rheem 40-gallon gas water heater that was installed last week. Here's the problem... Whenever someone takes a shower or we run the dishwasher, hot water will trickle out of the pressure relief valve. Then it stops. Does it sound like we have a faulty T & P valve? This seems kind of strange, since it's a brand new unit. This has been happening ever since the water heater was installed. We haven't had our water pressure checked, but we live in the city, and to my knowledge, none of our neighbors have complained about high PSI. Should we change the valve? Has anyone ever heard of this happening? Thanks.

Does the P&T valve leak at the SAME TIME as hot water is being used? Or does it leak AFTER the hot water has been used and the tank reheating and no water is being used?

When I turn on the hot water at the bathroom faucet and let it run, after about 3 or 4 minutes water will begin trickling out of the pressure relief valve. When I turn the faucet off in the bathroom, the water at the pressure relief valve will slow to a drip and then stop. Any ideas?

I have had cases where a brand new heater had a defective T&P and if this is the case the installer should be called back to replace the valve and take pressure readings.

If this didn't happen with the heater that was replaced then I would try the easiest approach first.

You should also get an idea of your incoming pressure as even city pressure can go over 100 PSI