Two distinct mechanisms for rent evolution
Indexation compensates inflation annually via the legal formula (health index). Revision adapts the rent to the real market value every 3 years. Both are distinct and cumulative.
Indexation and revision serve different purposes:
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Indexation maintains the landlord’s purchasing power by adjusting the rent to health index evolution. It is a quasi-automatic mechanism (upon written request) requiring no special justification.
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Revision allows adjusting the rent to the real rental market value. It is justified when new circumstances (works, neighbourhood evolution, property deterioration) have significantly changed the rental value.
Detailed comparison
| Criterion | Indexation | Revision |
|---|---|---|
| Legal basis | Art. 1728bis Civil Code | Art. 7 and 7bis Law on leases |
| Frequency | Annual | Triennial |
| Mechanism | Fixed mathematical formula | Rental value assessment |
| Condition | Written request | 20% minimum value variation |
| Initiative | Landlord (tenant if decrease) | Landlord or tenant |
| Procedure | Simple written request | Agreement or Justice of the Peace |
| EPC impact | Yes (regional restrictions) | No |
| Request deadline | On the anniversary date | 6 to 9 months before end of triennial period |
Indexation is a mechanical adjustment based on inflation. Revision is an economic adjustment based on market reality. Both can apply at the same time.
Can you combine indexation and revision
Yes, both mechanisms are perfectly cumulative. The landlord can:
- Index every year on the anniversary date
- Request a revision at the triennial deadline if the rental value has changed
After a revision, the revised rent becomes the new base for future indexations. The reference indices are also updated.
Example: a 9-year lease with a base rent of 800 EUR. The landlord indexes in years 1 and 2, then requests a revision at year 3 because neighbourhood works increased the rental value. If the court sets the new rent at 850 EUR, indexations from years 4, 5 and 6 start from this new base of 850 EUR.
Revision is not automatic. It requires either an amicable agreement or a procedure before the Justice of the Peace. The landlord cannot unilaterally set a new rent.
Regional specifics
Brussels-Capital Region
The Ordinance of 27 July 2017 maintains both mechanisms. EPC restrictions apply to indexation but not to revision.
Wallonia
The Walloon Decree of 15 March 2018 provides the same dual mechanism with identical conditions for revision.
Flanders
The Flemish Housing Rental Decree of 9 November 2018 governs revision with conditions specific to Flemish law, including the threshold for value variation.
Article 1728bis of the Belgian Civil Code and articles 7-7bis of the Law on leases — Coordinated text on Justel