Mandatory diagnostics before letting in Belgium
Complete list of mandatory diagnostics before letting in Belgium. EPC, electricity, detectors, asbestos: obligations by Region and costs.
Complete list of diagnostics by Region
| Diagnostic | Brussels | Wallonia | Flanders | Cost |
|---|---|---|---|---|
| EPC certificate | Mandatory | Mandatory | Mandatory | EUR 150 - 400 |
| Electrical compliance | Mandatory | Mandatory | Mandatory | EUR 150 - 350 |
| Smoke detectors | Mandatory | Mandatory | Mandatory | EUR 20 - 80 |
| CO detectors | Recommended | Mandatory (if combustion) | Variable | EUR 25 - 50 |
| Rental permit | No | Certain dwellings | No | Free |
| Asbestos certificate | No | No | Mandatory | EUR 200 - 500 |
| Soil certificate (OVAM) | No | No | Certain cases | Variable |
All these diagnostics must be completed before publishing the listing. The EPC must appear in the listing and all certificates must be annexed to the lease.
EPC certificate
The EPC certificate is the most impactful diagnostic. It determines the right to let (minimum scores), the right to index the rent and the valuation of the property.
| Element | Detail |
|---|---|
| Validity | 10 years |
| Cost | EUR 150 - 400 |
| Timeline | 2 - 4 weeks |
| Display obligation | Yes (in the listing) |
Since 2025, a minimum score is required for letting in Brussels and Wallonia. In Flanders, the threshold comes into force in 2028. See our guide on minimum scores by Region.
Electrical compliance
The electrical installation inspection is mandatory in all three Regions. A positive report is required before letting.
| Element | Detail |
|---|---|
| Validity | 25 years (if compliant) |
| Cost | EUR 150 - 350 |
| Timeline | 1 - 2 weeks |
| In case of violation | Works + new inspection |
For installations prior to 1981, an inspection is mandatory at each change of tenant. More recent installations must be inspected every 25 years.
If violations are detected, the landlord must carry out compliance works before letting. See our detailed guide on the electrical compliance certificate.
Other diagnostics by Region
Smoke detectors and CO detectors
Smoke detectors are mandatory in all three Regions (minimum 1 per floor). CO detectors are mandatory in Wallonia if the dwelling contains a combustion appliance.
Asbestos certificate (Flanders)
Since 2023, any property built before 2001 in Flanders must have an asbestos certificate before letting. The inventory is carried out by an approved expert. Cost: EUR 200 - 500.
Rental permit (Wallonia)
Mandatory for dwellings under 28 sqm, collective housing and dwellings above/below a business. Valid for 5 years. The application is free.
The asbestos certificate is a relatively recent obligation (2023) often overlooked by landlords. For a Flemish property built before 2001, it is an essential diagnostic to add to your checklist.
Planning and budget for diagnostics
| Diagnostic | When to order | Budget |
|---|---|---|
| EPC | 4 weeks before the listing | EUR 150 - 400 |
| Electrical compliance | 3 weeks before | EUR 150 - 350 |
| Detectors | Self-installation | EUR 50 - 150 |
| Asbestos (Flanders) | 4 weeks before | EUR 200 - 500 |
| Rental permit (Wallonia) | 6 - 8 weeks before | Free |
Total budget: EUR 400 - 900 in Wallonia/Brussels, EUR 600 - 1,400 in Flanders (with asbestos). These costs are tax-deductible via the 40% flat-rate deduction on rental income.
Plan diagnostics in advance to avoid delays. A rental management software alerts you on deadlines and centralises all certificates.