2023 REGIONAL URBAN DEVELOPMENT REGULATION ON RAINWATER

webmaster59208
Dec 14, 2023
2 min read

Have you heard of the 'GSVH 2023'? This is the regional urban development regulation on rainwater [1], a Flemish regulation on rainwater reuse that has come into force on 2nd October of 2023. This short info sheet gives a clear overview of exactly what has changed, so read on!

Why a new GSVH?

The previous ordinance on stormwater dates to 2013 [2]. Over the last 10 years, the climate in Flanders has changed considerably [3]: periods of long droughts, more extreme precipitation events and an even higher degree of built-on space. This necessitates new initiatives to protect our precious ecosystem. The goal of the Flemish government is to have the reuse and infiltration of rainwater adopted by everyone: private individuals, companies, and public authorities.

Who is covered by this GSVH? Which projects?

The regulation applies to both private and public land. In their technical document [4], Vlario (knowledge center for rainwater and wastewater in Flanders) summarizes which actions exactly fall within the scope:

The building or rebuilding or extension of covered structures along with projects where drainage works on existing covered structures are deemed necessary
Construction, reconstruction, or extension of pavements
Construction of a drainage system for the above structures/paving where rainwater was previously infiltrated naturally into the soil

There are, of course, a few exceptions and exemptions to the above provisions. All permit applications submitted, and all approved projects started before the GSVH came into force are already exempted. For more details, please refer to the above-mentioned technical document.

What (new) commitments should I add to my project?

With the new GSVH, the Flemish government obliges everyone to intervene in the above projects in 3 key topics:

Rainwater cisterns: larger cisterns, and obligation of at least one cistern starting from certain roof areas. This for buildings with 1, several or no residential units.
Infiltration facilities: Required minimum infiltration area is increased and preferably placed above ground
Buffer facilities: If infiltration cannot be provided, buffer facilities should be constructed if the drainage area is > 1000m2

Below are some numerical examples in line with the new obligations. If you have specific questions about your project, feel free to contact us!

Figure tables GSVH 2023