Cistern

[morpheus]

Despite turning the water off , my cistern is still filling itself up and overflowing

What do I need to do ?

Thanks

[Al-Glasgow]

cold water storage system do you mean ?.

I guess the ball valve is at fault, when you lift the arm the water should stop filling the tank.

Turn off the rising main, and service the ball valve.

Al

[fitz1]

probably tank fed from storage tank. look for big tank with two 22mm pipes coming off it. trace pipe to valves. if no valves , turn off the main and open all taps until water stops. fit isolation to toilet and refil. if this doesnt work, look for a second main, as some older houses used to have a main at the back of the house for the outside loo.