How do I determine whether there is a change to a more restrictive use?

This article explains when the Soil Decree requires a soil study as part of a permit application, and how to tell whether there is a change “to a more restrictive use”.

1. When does Article 23 of the Soil Decree apply?

Two conditions must both be met:

1. the land is recorded in the Banque de données de l’état des sols (BDES, soil status database) as polluted or potentially polluted;
2. the project includes one of the specified triggers: certain works affecting soil management (for example a change to the building footprint), or a change to a more restrictive use.

In that case, an orientation study (or a combined study) must be carried out, subject to the exemptions, derogations and waivers provided for in the decree. See the UVCW article on Article 23.

2. The soil form, attached to the application

The permit application is accompanied by the form on soil management and remediation (“Annexe BDES” (BDES annex) in Airplan). This form is what allows you to check whether one of the triggers applies.

3. Legal use, actual use, use adopted

The Soil Decree defines five types of use, from the most restrictive to the least restrictive: I natural, II agricultural, III residential, IV recreational or commercial, V industrial.

• The legal use derives from the planning designation of the property (sector plan, local orientation scheme, etc.), converted into a type of use by Annex 2 of the Soil Decree.
• The actual use corresponds to what really happens on the land, converted by Annex 3.
• The use adopted: for both the current and the planned situation, the form adopts the more restrictive use of the two.

There is a change to a more restrictive use when the planned use adopted is more restrictive than the current use adopted. Comparing actual uses alone can lead to the wrong conclusion.

4. Two examples

A shop converted into dwellings, in a residential zone:

The use adopted remains III: this project does not involve a change to a more restrictive use. Another trigger, such as works affecting soil management, may however apply.

An industrial site converted to housing after a change of designation:

The use adopted goes from V to III: this is a change to a more restrictive use. If the land is recorded in the BDES as polluted or potentially polluted, Article 23 applies.

5. In Airplan

Airplan picks up the sector plan designation and the BDES zone detected on the plot, which helps you fill in the soil form. You still need to enter the actual uses, current and planned: the conclusion depends on these answers.