Why is my temperature/pressure relief valve leaking?

Sounds like you over filled the tank after the flush. The hot water tank needs some air to allow for pressurization due to heating up water pressurizes the tank.

Put a bucket under the over flow/pressure valve pipe. Turn off the supply, and open it to release the pressure and some water - just about a gallon if that much comes out. Then turn the water on and check if it still leaks, if so, try that several times.

If it does still leak, then replace it, they are not too expensive, and actually easy to do, but the test above is free.

the city might have put in a examine valve on the meter to maintain water out of your equipment from backing up for some unknown reason and contaminating the municipal water furnish. while the chilly water in the heater gets heated from fifty 9 to one hundred twenty five tiers it expands slightly. perchance a cupfull. devoid of place to pass, it opens the relief valve. you could might desire to place in a ramification tank close on your water heater. that's a metallic tank a pair of gallon in length with a bladder interior packed with air. i don't have one, yet I be conscious an incredible sort of properties have them now. additionally decrease the drain so which you already realize it is not plugged or leaking.

Old age is the cause. The fix is simple, replace it. DIY stores have them. Have you got a pipe wrench and teflon tape?