[al holt]

our water heater is 6 years old, but in the last six months the t & p valve started leaking, and all the valves i've Changed want to leak. the temp has been the same for years. (I also cut back on the temp, no change) This is nutty . any ideas ... thanx al.

[AmpDraw]

If you've changed the T&P valve and its still leaking then obviously your tank temperature or pressure is going above the rating on the valve. I doubt its just your water line pressure, but the pressure in the tank does increase with over temperature. Either the Tstat is bad and causing it to over heat or you have a element thats shorted out and causing the element to heat even after the tstat has stopped calling for more heat. Guessing this is an electric water heater that is. If its gas then again the tstat could be the problem or the gas valve isn't always closing once the tstat is satisfied.

Sometimes, particularly if you've lifted the lever on the T&P valve to test it, they can stick slightly open. I usualy tap on the top of the lever with a paier of pliers or something to make sure it seats properly after testing them.