Two distinct and cumulative mechanisms
Yes, indexation and revision are distinct and cumulative. The landlord can index every year (health index formula) and request a revision every 3 years (if the rental market value has changed by 20%+). After a revision, the revised rent becomes the new base for future indexations.
The two mechanisms serve different purposes:
| Aspect | Indexation | Revision |
|---|---|---|
| Purpose | Compensate inflation | Adjust to market reality |
| Frequency | Annual | Every 3 years |
| Formula | Automatic (health index) | Market value assessment |
| Initiative | Landlord (written request) | Landlord or tenant |
| Court involvement | No | If no agreement reached |
How indexation and revision interact
When a revision occurs, the relationship between the two mechanisms changes:
- Before revision: the base rent from the original lease is used for indexation
- After revision: the revised rent becomes the new base for future indexations
- Index reset: the starting index is updated to reflect the revision date
This means a revision effectively “resets” the indexation calculation with a new base rent and new starting index.
If you believe your property’s market value has significantly changed (neighbourhood improvements, renovations, new transport links), consider requesting a revision at the triennial deadline. This can be more impactful than indexation alone.
Practical example
A 9-year lease with a base rent of 800 EUR:
- Years 1-2: indexation applied annually (e.g., rent reaches 832 EUR by year 2)
- Year 3 (triennial): revision requested because neighbourhood renovation increased the rental value. Court or agreement sets new rent at 880 EUR
- Years 4-6: indexation applied on the new base of 880 EUR
- Year 6 (second triennial): another revision opportunity
- Years 7-9: indexation continues on the last base
The combined effect of indexation and revision ensures the rent tracks both inflation and market reality.
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 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 Civil Code (indexation) and articles 7-7bis of the Law on leases (revision). Both mechanisms are legally independent and cumulative.