Repair Cisterns - Tips for Common Problems

Toilets are used daily without paying particular attention to them. Not many people notice how high the demand is, especially in the domestic WC. Attention, the toilet usually gets attention only when it is broken: The water suddenly flows continuously from the cistern or the toilet flush can not be operated. Such a broken cistern is not only annoying, but is permanent in the money: If the cistern is leaking, it may happen that depending on the defect present hundreds of liters of water are wasted. Of course, this drives up the water bill accordingly.

In such cases, however, you do not have to replace the entire cistern immediately or even buy a completely new toilet, because repair is often possible. In the following, we will explain you the problems that most often occur with cisterns and have written you a guide to each defect. Often, you do not need a lot of technical know-how, because small damages on the surface-mounted cistern can be easily repaired: sometimes you just have to clean the float or change defective seals. We'll tell you how to do it the best.

What types of cisterns are there?

The cistern is unremarkable on most lavatories. Mostly he is therefore hardly consciously perceived. Nevertheless, this element of the WC is the first port of call when there is a defect. Various cistern systems are available:

  • Rinsed cisterns - so-called surface-mounted cisterns
  • High-mounted cisterns that are located just below the ceiling
  • Concealed cisterns - for example from Geberit

The first version is furthest common. If you have such a cistern at home, you benefit from the fact that you can do the repairs yourself. The situation is different with a concealed cistern. Although it looks visually very beautiful, it can only be repaired with great effort.

Opening the cistern - How it works

All cisterns work according to the same principle. They differ only by the operation and their position. The attached cistern is the easiest to open: If it is a ceramic version, you usually only have to remove the cistern lid. Plastic versions are often hooked, so you need to apply a bit of force to loosen the lid. Cisterns that hang tightly under the ceiling are nowadays only available in old buildings.

Most tall-hanging models do not have the lid completely, so the cistern is immediately accessible.

However, you need to climb a ladder to make repairs. For concealed cisterns access is usually via the switch for flushing. This plate is often simply plugged in and can be removed with a screwdriver.

Common Problems with Cisterns

Once you have opened the cistern, you can look at it from the inside. It consists of a few simple components. However, they can wear off over time: Deposits, dirt and wear make important components such as the angle valve or filling valve unusable so that it no longer closes properly and the flushing water runs permanently. But flexible hose, gaskets and the moving elements of the mechanics, such as the float, can also be a problem.

One of the most common cistern malfunctions is the water flowing through. You recognize it by a permanent flow of water in the toilet bowl and a cistern that does not fill up again. In addition, often hooked the flushing mechanism. Before you can start the repairs, you must remove the actuator arm. Only then can the drain plug - which is also known as a Heberglocke - pull up. After that, the water runs off, so that you can examine all the components exactly. A flashlight will help you detect any defects.

What materials and tools do you need?

Prepare the following materials and tools before starting to work.


  • Seals
  • Float
  • Actuator Arm
  • Flexible Hose

Which materials you need, of course, depends on the defect. Therefore, first find the cause of the problem and then buy the appropriate accessories in the hardware store.


  • Flashlight
  • Wire Brush
  • Screwdriver
  • Special Cleaner
  • Water Pump Pliers

As soon as you get everything work can begin.

How to change the seals on the cistern

First check the seals. Are they worn or show visible traces of lime? Then it is best to remove them and replace each with a new seal. Most cisterns have two seals: one at the top inlet and the other at the bottom of the cistern. Look carefully at both seals and check if they are dirty or porous. In the case of cracks or damaged areas, the seals must be replaced. If only a little limescale appears, it may also be sufficient to descale the cistern, so that replacement is not necessarily required. Once you are in and are actually replacing the gaskets, you should also clean the pipe openings.

Float repair and cleaning

If the drain from the cistern is leaking, the float may be too Problem has. It serves to detect the water level and to keep it at a constant level. In the first step you should check whether the swimmer has wedged in his guide or is stiff. If so, separate the wedged elements from each other. Be careful, as these components are usually made of plastic and could easily break.

Older floats are often made of foam. Therefore, they suck in the course of time with water full. These models are best replaced with more modern designs made of styrofoam or plastic.

It is often the case that the float is dirty or calcified. Then it is best to remove it and use a special cleaner to dissolve the lime. A wire brush can also be used to remove the dirt. Be careful not to break anything.

Replace broken valves

Unless you have checked both the float and the gaskets and have not been able to detect calcifications, damage or soiling, and the water still does not flow as it should to take a closer look at the valves. This applies to both the angle valve and the inlet valve. The sieve in the inlet can be dirty. Then you need to clean it or replace it. If a valve has severe signs of wear, contamination or damage, it must be completely replaced.

In any case, you should take the opportunity that the cistern is once open to inspect and clean all components, even if only an element is dirty, calcified or damaged. This will prevent any repairs from being made again in the near future.


When the cistern is broken, most of the time it is that the water is flowing permanently, the flush button will catch and catch the cistern no longer completely filled with water. Then you can open the cistern and check the valves, seals and float for damage.

Artikelbild: Yastremska /