A flatmate leaving does not justify a rent increase
No, the departure of a flatmate does not give the landlord any right to increase the rent. The rent is fixed in the lease and can only evolve through annual indexation or triennial revision. The number of occupants has no impact on the rent amount.
Belgian rental law is clear: the rent is determined by the lease agreement. Only two legal mechanisms allow rent changes:
- Annual indexation: following the legal formula based on the health index
- Triennial revision: adapting the rent to the real rental value every 3 years, if it has changed by at least 20%
The number of tenants or occupants is irrelevant to the rent calculation.
Legal mechanisms for changing rent
| Mechanism | Frequency | Basis | Requires |
|---|---|---|---|
| Indexation | Annual | Health index | Written request |
| Revision | Every 3 years | Market value change (20%+) | Agreement or court |
| New lease | At lease end | Free market | New contract |
A landlord who wants to charge more rent has no legal basis to do so merely because a flatmate leaves. The remaining tenant(s) are bound by the existing lease terms.
If you are a remaining tenant after a flatmate’s departure, you are responsible for the full rent unless the lease specifies otherwise. Consider finding a replacement flatmate to share the burden, with the landlord’s agreement if required by the lease.
What changes are possible when a flatmate leaves
While the rent cannot increase, other changes may occur:
- Lease addendum: a new co-tenant can be added with all parties’ agreement
- Charge redistribution: utility charges may need recalculation among remaining tenants
- Deposit adjustment: if the departing flatmate’s share of the deposit needs to be settled
- New co-tenancy agreement: the internal arrangement between flatmates may need updating
The landlord can require the remaining tenants to find a replacement to ensure all lease obligations are met, but cannot impose a rent increase.
Regional specifics
Brussels-Capital Region
The Ordinance of 27 July 2017 includes specific provisions for shared housing (colocation). The departure of one co-tenant does not affect the total rent amount.
Wallonia
The Decree of 15 March 2018 governs co-tenancy arrangements. The rent remains fixed regardless of tenant composition changes.
Flanders
The Flemish Housing Rental Decree of 9 November 2018 provides specific rules for co-tenancy (medehuur). The rent cannot be increased due to a co-tenant’s departure.
Article 1728bis of the Belgian Civil Code and regional rental legislation. The rent is a contractual element that can only be modified through legally prescribed mechanisms.