Cistern leaking - this may be the reason

If the toilet flush starts to run after, then this can be very quickly become really expensive. Depending on which defect is exactly present, then run every day loose 100 liters of water or even more unused down the drain. Therefore, if you do not want to risk getting a sinfully high water bill in the long term, you should definitely redress as soon as possible and repair the cistern. While it is certainly much easier to hire an installer to take care of the cistern's repair. However, this is not only an expensive affair, but also not always necessary. Not infrequently, these are only minor problems that cause the cistern to leak. Many problems can be solved in a few simple steps.

The most common reasons for a leaky cistern

The three most common reasons for leaking cisterns are:

  1. Defective seal
  2. Defective Inlet valve
  3. Defective float

Defective seal

Close the water inlet on the angle valve and actuate the flushing of the toilet to empty the cistern. Dismount the rinsing cylinder and remove it from the cistern. Now you can either descale or clean the seal of the flushing cylinder or replace it with a new one.

Defective Fill Valve

If the seal is in order, then sometimes the fill valve itself may be broken, causing it to stop closing properly and to continuously flush water into the cistern running. Not infrequently it is only about limescale deposits on the valve. However, you can easily remove the lime with, for example,

  • descaler
  • vinegar
  • vinegar essence

. However, if the valve shows material damage, it can easily be replaced with a new valve, for example, one from Geberit.

Defective float

By adjusting the float, you have the option of changing the amount of water in the cistern is running, regulate. Especially in older cisterns a float made of hard foam or polystyrene is usually installed, which can be soaked with water under certain circumstances with the years and thus lose its buoyancy. If this is the case, then he can not rise far enough through the incoming water and thus close the filling valve. You should then immediately remove the float and replace it with a new one. But it can also just be a technical defect, such as a jammed linkage. However, in most cases this can be quickly resolved by carefully adjusting it.

Countless liters of water can be wasted unused by a cistern that runs or drips continuously, depending on the extent of the damage. Such damage unnecessarily drives up the cost of the water bill. Therefore, a leaking cistern should be repaired as soon as possible.

Immediate steps for a leaking cistern

As soon as you discover that the toilet cistern is leaking, be sure to turn off the water supply immediately by turning the angle valve to the cistern. If you are in a tenancy, you should immediately inform your landlord so that he can take care of the immediate repair of the damage and can repair it. After all, contracting a craftsman to repair a flushing cistern is usually the responsibility of the homeowner.

Not every landlord or landlord is willing to pay the cost of repairing a toilet cistern. Take a look at the lease. If a clause is concealed here, that so-called minor repairs or repair work up to a certain sum are to be borne by the tenant, then you must pay the repair of the cistern itself.

Flush-mounted or surface-mounted

In the case of a flushing cistern, it generally does not matter at first whether this surface-mounted or flush-mounted surface is lying. Even if they seem to be completely different at first glance, they actually differ only by their appearance, but not in their function. In a concealed cistern, this is behind a trim panel, where he may have been either directly embedded in the wall, or it was a pretext built around the cistern. In both cases, you will need to remove the bezel to access the cistern. However, if the cistern is located directly above the toilet, it is even easier to open, as in this case only the lid must be pulled upwards.

Repair the toilet flush seals yourself and save money

Um To repair the cistern of the toilet, first close the angle valve. Then remove the lid of the cistern and remove the handle set. This can vary depending on the manufacturer. Make sure that nothing breaks. Now you loosen the crimp on the side of the cistern, with which the water supply was connected to the cistern. Remove any fittings that hold the fill valve in the cistern and remove the faucet from the cistern. Then you can also disassemble and remove the standpipe with the bell jaw and the bell seal by releasing it from the catch.

Now you have the opportunity to remove and clean both the seal from the bell jar and the seals of the filling valve and to descale or, if necessary, to replace it completely. Then you just have to reassemble everything, the cistern should be tight again.


When the cistern of a toilet gets old, it can leak. The reasons for this can vary greatly, but there are three major causes that are particularly common and easy to resolve.

Artikelbild: © Yastremska /