Once done refill the tank with cold water.
Overflow tank in attic leaking.
Stop the water feed into either of the water tanks by turning the.
Take the lid off each tank and check how high the water level is in each one.
This is a valve located on the water pipe that.
In all cases if you do not know which is the problem cistern then a visual inspection will tell you.
Go into the loft and take the lid off each tank.
A leaking overflow on the tank is a common cause of a faulty ball cock which is also known as a float operating valve part 1 or part 2.
In every attic there should be an isolation valve to the tank so there should be no reason to turn the mains water supply of until the emergency plumber arrives to fix the plumbing.
Rainy weather causes the first type of leak to be discovered.
A cheaper way to fixing a float operating valve is by replacing the valve but in some cases as experienced the valve is then weaker and no longer under manufactures guarantee.
To turn the water feed off on a toilet cistern use the isolation valve.
Flush the toilet to drain the water.
Use a flat head screwdriver to turn the screw a quarter turn clockwise.
The water level in a tank is too high so it is running out the overflow.
When removing the sludge try not to disturb the water too much as it could end up making its way down the overflow pipe.
The most common leaks coming through the ceiling from the attic would be the float operating valve followed by a burst pipe due to the cold or a joint on the pipe work that may of been knocked at some point.
These type of water leaks are easy to find but also easy to fix if your good at a bit of diy plumbing.
Your central heating system might also benefit from a powerflush to clear out any sludge debris or rust that s blocking the water from flowing properly.
At the very least shingles.