So what do I need to do?  It's not a torrent of water, but it's more than a drip.  A steady small stream, I guess I'd call it.

How old is the heater?



Yes, replace the valve first.  You also need to test the water pressure in your house as well.

What he said.

Water heater is 8 - 10 years old, I don't remember exactly.

If you still have water coming out of the to valve after the heater cools off , it's probably not the heater

99% chance it's just the tp

They should be operated every month to keep this from happening

Yeah

With the pressure and temperature valve failure, it could be 3 things. First is to understand how it works. Inside is a valve with a seal and that held in place with a spring. Overtime the spring can weaken or the valve seat or gasket can break down. If you have hard water a piece of sediment could have gotten in between the valve and seat causing a little gap.  When that happens it no longer seals and will cause a leak. Then other cause could be high city water pressure. This could be from high pressure coming from the supply line. Second could be a problem with the heating element or gas thermocouple. This could cause a dangerous over temperature or pressure situation. As you heat the water it expands. The best and really only fix is to replace the valve with an identical one. One thing to never do is plug the valve. This could cause a explosion of the water heater (not likely but it could happen).

Is there an expansion tank?  Quickly push in the schrader valve on the end of the tank for a split second, if water comes out you need a new expansion tank.

Likely just leaking due to seal breaking down as suggested above. Don't need to drain the tank, just shut off the water to the task, relieve the pressure by opening a hot water spigot, close it. Make sure all spigots are off creating a water lock, loosen but don't remove T&P, put pipe dope on new one, remove and immediately install new T&P. You'll lose maybe an ounce or two of water.

What he said. When the water is heated it expands, that expansion creates pressure in the system, because there is a one way valve (back flow preventer)  on the supply line coming into the house. That's why there's an expansion tank in the system.

The expansion tank has a rubber diaphragm in it that, over time will fail. They are cheap and easy to replace.

at that age, it is most likely the t&p

thermal expansion doesn't typically become an issue after 8-10 years

My house has a pressure blow off valve that would release the extra pressure from expansion. After a decade it got crapped up from mineral deposits and stopped working, so I had leaks caused by high pressure. I bought a new one and replaced it.

Mine had never operated to my knowledge.  One day, I decided to test it.  Of course, it started leaking and wouldn't stop dribbling hot water out the drain line.  Had to replace the valve with a new one.

open and close the valve and flush it out a bunch of times ,make sure the water is on you can leave the gas off .just needs a good flush .also turn the lever 90 degrees when open . it wont leak for years

This was a short term fix for me.  Stopped leaking for a couple of weeks, then I had to replace the valve.

Certainly worth a try.

Unless the expansion tank fails.

Worth a try, but it didn't help mine.  I tried the same thing with the same thought.  Opened and closed it probably 30-40 times.  Didn't help.



 

Wow, didn't realize this thread got so many replies.  I'll read through them all in case I need more help.



I replaced the valve and it seems to be fine now.