Help the development of the site, sharing the article with friends!

An irrigation system brings comfort, but also dangers. To avoid frost damage, Gardena garden irrigation systems have a drainage valve. But what to do if this is leaking?

In a nutshell

  • Even the best Gardena drainage valve wears out at some point
  • Foreign objects between the seals often prevent them from closing completely
  • If the water pressure is too low, the device will not trigger

How does a Gardena drainage valve work?

In order to be able to understand a possible source of error for a leaking drainage valve, basic knowledge of how it works helps: When not in use, i.e. without water-filled lines, the fitting is open. Even small amounts of water can drain away unhindered. The slider only closes via a spring mechanism when a specified pressure is reached. With Gardena valves, this point is usually reached at around 0.2 bar. Now the irrigation system can do its job. If the water supply is stopped again, the pressure drops. When the threshold is reached, the device opens and carries out the residual emptying.

problems and their elimination

There are various problems that can cause the drain valve to leak. Depending on the cause, the help required differs:

The wrong installation

Usually the drain valve is built into a gravel pack. In this way, escaping water can be absorbed and drained away. If the gravel is missing or too coarse, soil will eventually get into the drainage and can block the mechanism


  • expose the valve
  • Remove soil about 20 centimeters on all sides
  • Line the group with filter fleece
  • Bring in half of the washed gravel as a soakaway
  • Insert drainage device
  • Cover the top of the device with gravel
  • Fold the top side of the fleece over the gravel packing
  • apply soil

dirt in the water

If the irrigation water transports foreign matter such as dirt, sand or other particles in the irrigation system, these can also get into the drainage device. Then it can happen that although the drainage valve closes, the seals do not achieve a real seal. The water keeps running.


  • Remove drainage device
  • Rinse lines thoroughly with fresh water
  • Clean the device and check for damage to the seal
  • If necessary, replace the seal
  • Reinstall the drain valve professionally
  • Filter the irrigation lines at the inlet

Notice: The danger of dirt in the pipe is of course particularly high with rainwater. However, switching to drinking water runs counter to ecological considerations, so installing a filter in the irrigation system is clearly preferable.

roots in the valve

The drainage device will be buried in the ground together with the pipes for the entire system. It is therefore obvious that sometimes roots grow through the seepage packing to the seal. On the other hand, if they continue to grow between the individual sealing rings, the valve can no longer close completely and will leak.


  • expose drainage
  • Remove roots from fitting
  • Check seals for damage and replace if necessary
  • Lay drainage properly in gravel packing and cover

Tip: If the subsoil is heavily rooted, you can also keep roots away with a root fleece. Before installing the gravel pack, place it in the hollow in the ground and finally cover the top of the septic tank with it as well.

Defective seals

Even properly installed valves wear out over time due to the recurring closing and opening processes. Eventually, the seals will wear out and no longer perform satisfactorily.


  • Expose drain valve
  • Renew seals
  • Alternatively, replace the entire device
  • Reinstall with recovery of the drain packing

The wrong water pressure

In order to trigger the closing process of the valve, an overpressure is required in the water pipes. If this pressure is not reached, the water continues to flow unhindered.


  • Check lines for blockage and clean if necessary
  • increase water pressure
  • e.g. open the water tap further
  • e.g. increase pump performance

Notice: Damage can also be a cause of reduced water pressure. If the remedies mentioned do not help, you should check all the components involved one after the other and repair them if necessary.

frequently asked Questions

Can I do without the drainage device?

Of course you can do without drainage. However, you then have to empty your drainage system manually in winter. This can be done, for example, by blowing out with compressed air after you have removed an end cap.

Is it true that water is lost after each use?

It is true that every time the water pressure drops, there is a drain. This means that after each watering, a certain amount of water seeps into the ground.

Do above ground systems need a drainage device?

Above-ground irrigation systems often only remain in the flowerbed over the summer. Therefore, you can usually do without the device. If you dismantle before winter, drain the lines anyway.

Help the development of the site, sharing the article with friends!