Repairing an overflowing cistern

Repairing an overflowing cistern

There are many different types of cistern and also many different types of fittings within the cistern, this info is a guide only.


1. Fisrtly, you must turn off the water supply shut-off valve, this can be located on the left or right side of the cistern as the position of the inlet pipe can vary depending on the cistern.

2. Remove the cistern cover from the top, sometimes you may firstly have to remove the flush push button if your cistern has this type of flush.

Note; Lots of cisterns have a flushing handle on the front (as shown above) or the side which makes removing the top (lid) easier.

3. Flush the toilet to empty the cistern, you can also manually empty the tank by pulling the chain that's attached to the flapper inside the cistern.

Note; The flapper is the part that releases the water in the cistern to "flush" the toilet.

4. To disconnect the water supply (pipe) line, turn the nuts clockwise with a wrench.

5. Unscrew the bolts located at the bottom of the tank and at the back of the bowl but remember that cisterns are fixed in many ways, there should be no need to use force, if you feel you have removed all necessary fixing screws or bolts and the cistern or bowl won't budge it may be there are more fixings.

6. Remove the cistern from the bowl.

I. Replacing the flapper:

Note; use your camera phone to make a record of how the old one is fitted so you replace it in a similar fashion.

a. Unscrew the nut/screw holding the flapper.
b. Lift it out and dispose of safely.
c. Install a new flapper.

II.Replacing the seal:

a. To replace the seal, unscrew the nut between the base of the cistern and the flapper.
b. Pull off the old seal and replace it with a new seal.

7. Retrace your steps in terms of how you disconnected the cistern and bowl, fit the screws or the bolts and secure the cistern back on the wall and attach it to the bowl.

8. Turn on the water shut-off valve, check for leaks and flush to see if it is working properly.

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