Cistern drips: nothing drips anymore with these tips!

It's annoying, costs money and is a waste - when the cistern drips. After each rinse further water gets into the toilet. In some cases, a proper trickle comes out of the cistern. Owners should therefore not underestimate the problem, find causes quickly and remove them. Otherwise, several liters of water per day may flow unused.

Different causes for dripping cistern

For many cisterns, it is only a matter of time before they drip. Because the components are not immune to wear. Seals become hard or porous, mechanical parts break or jam. Also dirt and limescale deposits can clog the cistern and make it leaky. Common causes include:

  • Defective bell jaw
  • Defective filling valve
  • Porous gaskets
  • Wrong pressure of the cover
  • Limescale and Co deposits

Should the water not stop at all, should be considered first measure the water supply to the toilet are turned off. This is done at the angle valve in the supply line by hand or at the shut-off valve in the cistern. Tenants should contact their landlord, because he is responsible for the craftsman's appointment. Homeowners can also try to repair their cisterns themselves and save the expensive craftsman.

There are two basic types of cisterns: freestanding and those built into the wall. The steps inside the cistern are the same for everyone. With the built-in model, the cover must first be removed and the partition removed beforehand.

If the bell is leaky

The bell is an essential component in the water tank. It is connected to the water flushing button. If this is pressed, the bell is raised - water can flow out of the cistern.

If the water drips constantly, it may be because the bell is leaky. The handyman can also detect this if the water does not run into the overflow of the Heberglocke. Also the noise of the water when refilling the cistern is different: jerky instead of continuous.

If the cause is found here, only a replacement of the Heberglocke helps. However, these parts are not standardized, so the manufacturer and product number are needed to find the right replacement part. The handyman finds the number in the cistern next to the angle valve.

The replacement itself, however, is usually unspectacular: Carefully loosen the Heberg Cradle Holder from the rear wall, detach the Heberglocke and insert the new one. In some cases, the heel bell neck must be split into two parts as an intermediate step.

A broken filling valve as cause

If the toilet cistern licks, this can also be due to the filling valve. This important component is responsible for filling the water box. The so-called float on the valve detects the water level. If it is low, the box is filled. If it is high, the float valve closes again.

However, if the float valve does not close properly, the toilet may drip. Often this is also recognizable by the permanent water noise - the float usually does not recognize at the same time that the cistern is full. In some cases, only limescale is at fault here and cleaning is sufficient. However, if the float is broken, the filling valve should be replaced. Depending on the Spülkastenmodell can usually easily find a suitable spare part. Numerous suppliers also offer universal filling valves.

The replacement works simply: open the cistern, close the inlet valve and remove the filling valve from the holder. The inlet hose can be loosened with a pair of pliers or a fork wrench. The new valve is screwed back to the inlet hose and pressed into the holder.

Spare parts are available from different companies. Geberit, Wisa, Jomo and Schwab are leaders in this area.

Porous gaskets are the cause

But even gaskets that no longer function completely can be the cause of dripping toilet flushing. Over time these become automatically hard and porous - the plasticizer in the rubber seals fades. As a result, the seal ring contracts and becomes smaller - the seal becomes permeable.

In many cases this affects the seal under the float, in the bell jar or at the inlet valve. The craftsman should check all here. When buying it also requires the manufacturer and number of the cistern, because seals are also not standardized. If you do not have these at hand, you should remove the seal and measure the inner, outer diameter and thickness.

Actuator Places Wrong Pressure

In some cases, the cistern drips immediately after installation or even after maintenance. Then, if everything is ok, it does not seem to work anymore. In these cases, the flush button is usually the cause.

The handle bar was screwed out too far during cleaning or installation. As a result, the actuator plate exerts permanent pressure on the rod - and sends quasi the mechanical signal: water march. The bell is lifted slightly and water flows or drips into the toilet bowl.

This defect is easily remedied once it has been detected. Turn the lid on, push the presser bar further in and close the cistern again.

Cistern Curing

The last cause is also very frequent: calcination of the cistern. The deposits ensure that the mechanical parts no longer function properly. In this case, a cleaning is sufficient and the components do not always have to be replaced. For example, this is often the case when the floater on the filling valve is contaminated with lime.

Vinegar essence, citric acid or dilute hydrochloric acid are suitable for decalcifying the cistern. These are placed in the open cistern and the water box is best so soaked overnight. The craftsman can also remove the moving parts and additionally soak in a bowl. After the action follows the purge. Here a wire brush can be used. Once everything has been cleaned, the cistern can be rebuilt together. Multiple rinsing is then advisable. Will the cistern continue to drip? Then maybe not just lime, but one of the other causes is to blame.


When the cistern drips, many liters of water can be wasted unused through the toilet. This not only cuts the wallet, but is also not very environmentally friendly. For a dripping cistern may be different reasons. In any case, the water supply should be turned off before the cause research starts.

Artikelbild: © Yastremska /