If the cistern is leaking from the toilet


Almost everyone has seen a leaky toilet before. The water runs in a more or less large trickle continuously from the cistern through the toilet in the drain pipe. That's not just a big environmental damage. Also, the costs are not insignificant in the high water and sewage prices. If the toilet is leaking from the toilet, you should do something about it as soon as possible. Below we have compiled for you not only different procedures, but also causes of leaking toilet cisterns.

Leaks outside, but caulk around the cistern

A cistern, which is leaking at the connecting lines (from the cistern to the toilet), is unlikely. That's why we do not want to go into that. Either the seal must be exchanged or the outer thread for sealing newly wrapped with hemp. The situation is similar between the following components:

  • from the water connection to the angle valve
  • from angle valve to flexible hose
  • from the flexible hose to the inlet valve

If only the respective connections are leaking, you can proceed as already mentioned. Otherwise it could also be that one of the respective parts (angle valve or inlet valve) has a defect. However, you can carry out the check during the entire procedure for damage determination.

Systems available from us

Basically, there are no differences in the operation of a toilet cistern. But you have to differentiate according to the structural engineering systems, so that you get differently to the mechanics inside the cistern. The following toilet systems are common with us:

  • Standing toilet with cistern on top
  • Stand-up toilet with high cistern (old building, just below the ceiling)
  • Wall or hanging toilet with cistern on top
  • Wall or hanging toilet with invisible cistern behind the stem wall

Attached cisterns

Freely accessible cisterns placed on the toilet are either made of plastic or ceramic (porcelain). The ceramic covers are usually only hung up because they have enough weight. Plastic lids, however, are usually plugged. With a quick jerk you can be removed.

Cistern in the stem wall

The high-hanging toilet cistern in the old building, which is operated by a pull chain, usually has no cover at all. For this you need a good ladder here. Remain the pre-wall element toilet, in which the cistern is integrated inside the stem wall. Access is via the flushing button, which is usually plugged and can be removed with a screwdriver.

The mechanics in the cistern

All further work steps are not very different from each other. The operation may still differ. The plastic stopper, which is opened for rinsing, can also serve as an overflow. It can also be combined with the float or completely independently connected only with the flush button. The systems are always very similar. However, the leakage of the toilet cistern may have various causes:

  • calcium deposits
  • other deposits (mud, sand, algae) on seals or the moving mechanics of the inlet valve
  • porous or hardened sealing rings (under the float and at the inlet valve)
  • rarely a broken swimmer

Perform all work (descaling and mechanical inspection)

You should not think twice about what to check first. All work is done quickly, as long as you do not need any spare parts, using the traditional means found in any well-managed household. If, later on, a mechanical defect should turn out instead of leaks due to deposits, you have cleaned at least the complete cistern mechanism including cistern and again for many years rest.

Step by step instructions for repairing a leaking cistern

  • possibly new seals (under the float and at the inlet valve)
  • Cleaners and limescale solvents (commercial lime cleaner, acetic or citric acid etc.)
  • hemp
  • fine soft wire brush (toothbrush size or smaller, made of copper or similar soft)
  • Wasserpumpenzange
  • Fork / wrench
  • flashlight
  • screwdriver
  • depending on the cistern system a ladder
  • big water tank like bucket

1. Prepare the cistern

First you need to remove the lid, as we have already described. Then turn off the water. Preferably at the angle valve near the cistern. If there is no such valve, you must turn off the main tap.

2. Disassemble the inlet mechanics

Suspend the lever arm from the float to the inlet valve. This inlet valve is countered at the cistern with a nut. Loosen the nut on one side and pull out the valve in the other direction. There are also cisterns in which the inlet valve is in the cistern and from the bottom (outside) is screwed. The purge port can either be pulled up or screwed.

3. Allow to act with limesolvents

Now put all the items in the bucket with your limescale remover. Depending on what you use, you must take note of the respective mixing ratio. Also insert the seals and the float. In the meantime, spray the cistern with a lime remover one. If everything could work for a few hours (can also be used overnight), cleaning will begin

First remove limescale from the seal that comes under the float. Also clean the float with the wire brush. If the gaskets are hard or porous, renew them - which we would recommend for older toilets anyway. Then you also brush the lime residues from the cistern. Finally, clean the inlet valve, the mechanically moving parts, the connecting holes and pins as well as the movable arm.

Always operate the valve by hand. You may also be able to spray it vigorously with Rust Remover and move it again and again. Once everything has been cleaned, the assembly begins.

4. Check that the cistern is now tight

Once everything is assembled, let the water run in. If the seal on the float was leaking, which you renewed (and cleaned the cistern of the lime), now runs no more water. However, if it still runs, the problem is probably the mechanics of the inlet valve. It has to close in the exact right position. You may need to reset the float. Does not help, the inlet valve must be renewed.

Tips & Tricks

In addition to leaking cisterns clogged toilets are a problem. What to do when the toilet is clogged, learn here.


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