The answer depends on how charges are structured

Quick answer

Flat-rate charges cannot be increased unilaterally during the lease. Actual charges (provisions with annual settlement) can be adjusted to reflect real costs, provided the landlord supplies supporting documents. The lease must clearly state which system applies. All three Belgian regions protect tenants against unjustified charge increases.

Belgian rental law distinguishes between two charge systems. Flat-rate charges are a fixed monthly amount that covers all ancillary costs — the landlord bears the risk of under- or overestimation. Actual charges are monthly provisions adjusted annually based on real expenditure, with a formal settlement statement.

The choice between flat-rate and actual charges must be clearly stated in the lease. If the lease is silent, courts generally interpret charges as flat-rate, which prevents the landlord from requesting additional payments.

Types of charges and their treatment

Charge typeCan be increased?Conditions
Flat-rate (forfait)No (without agreement)Requires written addendum signed by both parties
Provisions (actual)YesMust be justified by supporting documents
Indexation of chargesOnly if provided in leaseFollows the health index, like rent
Common area costsYes (if actual)Based on co-ownership settlement statements

Common charges covered include water, heating of common areas, lift maintenance, building insurance, cleaning of common areas, and rubbish collection. The landlord’s own expenses (mortgage, structural repairs, property tax) may never be passed on as tenant charges.

Practical tip

Always request the annual charge settlement statement. The landlord must provide it with supporting documents. You have the right to verify the underlying invoices. If the settlement shows an overpayment, the landlord must reimburse the difference.

Challenging an unjustified charge increase

If you believe the landlord has unjustly increased charges, several remedies exist:

  • Formal request — send a registered letter asking for a detailed breakdown with supporting documents
  • Mediation — contact the local mediation service for rental disputes
  • Justice of the peace — file a claim before the justice of the peace of the district where the property is located
  • Request reimbursement — if you have overpaid, you can claim reimbursement for up to 5 years of overpayments

The burden of proof lies with the landlord. They must demonstrate that the charges are justified and correspond to actual expenses incurred for the rented property.

Regional specifics

Brussels-Capital Region

The ordinance of 27 July 2017 requires the lease to specify whether charges are flat-rate or actual. The landlord must provide an annual settlement with supporting documents for actual charges. A list of chargeable and non-chargeable expenses is annexed to the ordinance.

Walloon Region

The decree of 15 March 2018 contains similar provisions. The Walloon government has published a detailed list specifying which charges may be passed on to the tenant and which remain the landlord’s responsibility.

Flemish Region

The Vlaams Woninghuurdecreet of 9 November 2018 requires precise specification of charges in the lease. Flanders also publishes a list of tenant-chargeable costs. The landlord must provide the settlement statement within a reasonable period after the end of the charge year.