Yes, the surface area must be mentioned in the lease
The lease must mention the habitable surface area of the rented property. This is a mandatory requirement under regional housing legislation in all three Belgian regions. The surface area helps define the property, set appropriate rent levels, and prevent disputes. If the stated area differs significantly from reality, the tenant may claim a rent reduction.
The obligation to mention the surface area is part of the broader requirement for a complete property description in the lease. Along with the address, property type, number of rooms, and EPC rating, the surface area gives tenants essential information about what they are renting.
The surface area mentioned should be the habitable surface area (superficie habitable / bewoonbare oppervlakte), which typically includes all rooms with a ceiling height of at least 2 metres (or 1.80 m in some regional definitions). Cellars, garages, and terraces are generally excluded from the habitable surface area but may be mentioned separately.
How to measure and state the surface area
Measurement rules:
- Use the interior floor area (measured from the inside of the walls)
- Include rooms with a minimum ceiling height of 2 m (varies by region)
- Include: bedrooms, living room, kitchen, bathroom, hallways
- Exclude: cellars, garages, attics below minimum height, terraces
- Measure in square metres (m2)
How to state it in the lease:
- “The habitable surface area of the property is approximately [X] m2”
- Use “approximately” (environ / ongeveer) to account for measurement variations
- List additional spaces separately if relevant (e.g., “garden: 50 m2, cellar: 15 m2”)
BailBelgique includes a dedicated surface area field in the lease creation form. The platform reminds you to measure correctly and uses the appropriate legal terminology for your region.
Consequences of surface area errors
If the actual surface area is significantly different from what is stated in the lease:
| Situation | Tenant’s rights |
|---|---|
| Area is 10%+ smaller than stated | Rent reduction proportional to the shortfall |
| Area is 20%+ smaller than stated | Possible lease cancellation |
| Area is larger than stated | No additional rent owed |
| No area mentioned | Lease may be considered incomplete |
The tenant’s claim for rent reduction is based on the principle that they pay rent for a specific property as described. If the property is substantially smaller than described, the value received is lower than the value paid for.
As a landlord, always measure the property accurately and honestly. Overstating the surface area to justify a higher rent can lead to disputes, rent reductions, and even lease cancellation. When in doubt, have the property measured by a professional and use the word “approximately” in the lease.
Regional specifics
Brussels-Capital Region
The Brussels Housing Code requires the habitable surface area in the lease. Brussels also has minimum surface area requirements for rental properties: at least 18 m2 for a studio and additional requirements per bedroom.
Wallonia
The Walloon Residential Lease Decree mandates the surface area mention. Wallonia applies the General Regional Housing Code (CWATUPE) quality standards, which include minimum surface area requirements.
Flanders
The Flemish Housing Rental Decree requires the surface area and links it to the Flemish Housing Quality standards. Properties must meet minimum surface area requirements to be legally rentable.
Regional housing legislation requires surface area mention in all residential leases. Brussels: Ordinance of 27 July 2017. Wallonia: Decree of 15 March 2018. Flanders: Decree of 9 November 2018.