Indexation can be waived contractually
Yes, the parties can waive rent indexation in the lease. The right to indexation is not a matter of public order for residential leases — it can be contractually excluded. The waiver must be clear and explicit. It can be total (entire lease duration) or partial (limited period). The waiver cannot be imposed retroactively without mutual agreement.
While rent indexation is a legal right for primary residence leases, it is not an imperative (mandatory) provision. This means the parties can agree to exclude it. The landlord may offer to waive indexation as a negotiation tool — for example, to attract a good tenant or in exchange for a slightly higher base rent.
The key requirement is clarity: the waiver must leave no room for doubt. Ambiguous clauses will be interpreted in favour of the landlord retaining the right to indexation.
How to draft an indexation waiver
| Type of waiver | Clause example | Effect |
|---|---|---|
| Total waiver | ”The landlord waives the right to annual indexation for the entire lease duration” | No indexation possible |
| Temporary waiver | ”No indexation during the first 3 years” | Indexation resumes after 3 years |
| Conditional waiver | ”No indexation if inflation stays below 2%“ | Indexation triggers above threshold |
| Reciprocal waiver | ”Neither party may claim indexation” | Fixed rent throughout |
The waiver clause should:
- Explicitly mention indexation — do not use vague language
- Specify the scope — total, temporal, or conditional
- State the base rent clearly — the fixed amount that will not change
- Be included in the lease — not in a separate informal document
As a landlord, carefully consider the long-term impact of waiving indexation. Over a 9-year lease with average inflation of 2%, you would lose approximately 16% of the rent’s purchasing power. As a tenant, an indexation waiver provides valuable budget certainty.
Long-term consequences of waiving indexation
Waiving indexation has significant financial implications:
- For the landlord — the real value of the rent decreases with inflation. Over 9 years at 2% average inflation, the rent loses about 16% of its purchasing power
- For the tenant — budget stability and protection against sudden increases
- At lease renewal — the landlord can set a new rent at the end of the 9-year period, potentially catching up with market rates
- During the lease — the landlord cannot use the rent revision mechanism (justice of the peace) solely to compensate for the waived indexation
If the waiver is temporary, the indexation that resumes uses the original base rent and base index, not an updated one. This means the “missed” years of indexation are not recovered.
A waiver included in the original lease is binding for the entire duration. It can only be reversed by a written addendum signed by both parties.
Regional specifics
Brussels-Capital Region
The ordinance of 27 July 2017 does not prohibit indexation waivers. Brussels courts recognise them as valid contractual provisions. The waiver must be clearly drafted to be enforceable.
Walloon Region
The decree of 15 March 2018 similarly allows indexation waivers. Walloon courts interpret ambiguous clauses in favour of the landlord’s right to indexation.
Flemish Region
The Vlaams Woninghuurdecreet of 9 November 2018 permits indexation waivers. Flanders requires that the waiver be explicit and unambiguous. Note that energy-related indexation restrictions are separate from contractual waivers and apply regardless.
Regional housing legislation on rent indexation. The right to indexation is not a public order provision and can be contractually waived. Civil Code, art. 1134 (contractual freedom).