Two things can cause the valve to drip or leak. First you need to put a "AIR POCKET" back in the hot water tank.
#1 Turn off the water supply at the pump or faucet that your hose is
hooked to. Turn off the gas/ electricity to hot water tank.
Open the hot water faucet in the kitchen and bathroom, leave open!
Open the pressure relief valve by hand (wear gloves if water is hot).
Let drain until the water stops running or dripping.
At this time when water stops, "SNAP" close the relief valve several
times, 3-4 times, leave valve closed.
Close the hot water faucets in the kitchen and bath.
Turn water supply back on, let tank pressurise. Turn gas or electric
back on. Let water get hot ( I would use the gas to heat water for a
After gas heat shuts off, check for any dripping, If none, you have
just saved yourself the price of a new pressure relief valve and time to install it.
#2 BUT IF IT STILL LEAKS AFTER PUTTING THE "AIR POCKET" BACK INTO
THE TANK, Procure a new relief valve, install. Follow instructions
for putting air pocket into tank.
A word of CAUTION, never open the pressure relief valve when water is
hot and UNDER PRESSURE.
If you snap open the pressure relief valve while under pressure, you will
always lose the air pocket.