Dripping overflow

[scoobydoo2]

HI have got a dripping overflow from my hot water tank I've checked the ballcock and that seems fine. Any ideas on what could be causing it as I'm wasting so much hot water draining it off to stop the drip,

[burnhal]

Its either the setting of the ballcock- ie it doesnt rise quite enough to shut off the valve before the tank overflows. See if its adjustable- most have an adjuster on the valve actuator. Other than that the valve is defective and the float arm-valve assembly needs changing. Not an expensive job and something most people can do easily.

[markja]

might even only need a new washer in the valve.
if you pull gently on the ballcock does the drip stop? new washer 50p from hardware shop. you will need to know what the old one looks like though.