How can I stop my water tank overflow running constantly? ?

check to seee if ball valve working properly, if no water coming out of the valve when the float rises then it could be water coming in from the cylinder. This has happened to me too, i replaced the ball valve but still water in the tank fills up very slowly, if thats the case you have to call in the experts. If its the ball valve you can change it yourself. You can buy a new ball valve in B&Q for around £5 including the float

stephen
August 2009

fit a new ballcock

alan
May 2009