What is the purpose of the non-return valve?


The non-return valve is mandatory for every private water system in Wallonia. This device must prevent any return of water from the private system to the distribution network.  


What is its purpose?

Its function is to allow water to pass through the pipes in one direction only: from our distribution network to your private system. It must prevent any backflow of wastewater into the system, which could deteriorate the quality of the water supplied and cause inconvenience to all consumers.   

Where is the non-return valve located in your system?  

It is placed just after the bleed valve after the water meter (in the direction of water flow).

Schéma install 05.05.2024 FR



Since 1 June 2021, all new connections are fitted with a non-return valve

If your connection dates from before 1 June 2021, make sure it is fitted with this device. If this is not the case, you will have to do the installation yourself. 

You are responsible for maintaining, repairing or replacing the non-return valve.

Who is responsible for what and when?  

What is the purpose of the backflow preventer and when should it be installed?  

The installation of a backflow preventer is highly recommended for hospitals, homes, nurseries, industries, etc. 



This device is equipped with two non-return valves separated by a discharge chamber. The backflow preventer protects drinking water systems by interrupting the continuity of the supply to the private system by self-draining and draining the liquid if there is a danger of wastewater flowing back into the public supply pipe.  


Don't forget!  

All connections must be fitted with a non-return valve approved by SWDE or any other distributor. It is maintained, repaired or replaced by you at your own expense.  

The list of approved non-return valves is available in the directory of technical requirements for indoor systems on the Belgaqua website.