My rent increased: is this legal?
Sofie, a tenant in Ghent, receives a 90 EUR rent increase outside of legal indexation. How she challenged it and obtained reimbursement of the overpayment.
- 01 The increase
- 02 The doubt
- 03 The verification
- 04 The challenge
- 05 The result
- 06 What I learned
January 2025 — the increase
My name is Sofie, I am 35 and I work as a nurse at UZ Gent. I have been renting a 2-bedroom flat in the Ledeberg neighbourhood of Ghent since September 2021. Initial rent: 740 EUR. After indexation in 2022, 2023 and 2024, my rent had reached 760 EUR. A standard 3-6-9 primary residence lease.
On 5 January 2025, I received a letter from my landlord, Mr Van Hoeck: “Following the facade renovation work carried out in 2024, the rent is raised to 850 EUR from 1 February 2025.” An increase of 90 EUR per month, +11.8%.
The letter mentioned neither legal indexation, nor a triennial revision, nor any legal basis. Just “facade work” as justification.
February-March — the doubt
I do not know much about tenancy law. The letter seemed official, Mr Van Hoeck has always been correct. I assumed the facade work probably justified an increase. I paid 850 EUR in February, March, April and May.
It was a colleague, also a tenant, who alerted me in April: “90 EUR increase in one go? That doesn’t seem right. Go check.” She was right.
In Belgium, a landlord cannot freely increase the rent during a lease. Only annual indexation (linked to the health index) and triennial revision (under strict conditions) are permitted. Any other increase is illegal.
April 2025 — the verification
I contacted the Huurdersbond (tenants’ union) in Ghent. Free consultation. The adviser examined my lease and Mr Van Hoeck’s letter. Diagnosis in 10 minutes:
1. Legal indexation authorised an increase of 18 EUR, not 90.
The calculation: base rent (740 EUR) x current health index / health index of the month preceding the signing = 778 EUR. That is +18 EUR, not +90.
2. Triennial revision was not applicable.
My lease started in September 2021. The first triennial period ends in September 2024. The revision can only be requested in the last 3 months of the triennial period (June to August 2024). Mr Van Hoeck’s letter dates from January 2025 — too late.
3. Facade work does not justify a free increase.
Even within a revision, the work must increase the rental value by at least 10%. A facade facelift is normal maintenance at the landlord’s expense, not an improvement to the property.
The legal formula: base rent x new health index / starting health index. You can verify the calculation on the FPS Economy website. If the amount requested by the landlord exceeds this result, the increase is contestable.
In short: Mr Van Hoeck was entitled to a rent of 778 EUR (legal indexation). He was claiming 850 EUR. The 72 EUR per month difference had no legal basis.
May 2025 — the challenge
On 8 May, I sent a registered letter to Mr Van Hoeck. The letter, drafted with the help of the Huurdersbond, contained:
- The detailed calculation of the legal indexation (740 EUR to 778 EUR)
- A reminder of the triennial revision conditions (deadline passed)
- A request to return to the legal rent of 778 EUR from June
- A request for reimbursement of the overpayment: 4 months x 72 EUR = 288 EUR
- A 15-day deadline to respond, failing which I would refer the matter to the justice of the peace
Mr Van Hoeck called 3 days later. He genuinely believed he had the right to increase the rent after renovation work. “My accountant told me the facade work entitled me to a revision.” The Huurdersbond adviser had warned me: many landlords confuse renovation and revision, in good faith.
Stay factual and courteous. The goal is not to punish the landlord but to restore the legal rent. Most abusive increases come from a lack of knowledge of the law, not bad faith. An aggressive tone blocks the negotiation.
June 2025 — the result
After an exchange of letters, Mr Van Hoeck accepted:
- Rent brought back to 778 EUR (legal indexation) from June 2025
- Reimbursement of 288 EUR (overpayment from February to May) in the form of a rent reduction: 3 months at 682 EUR, then return to 778 EUR
- Commitment to only request the next indexation on the lease anniversary date
The agreement was formalised through an exchange of registered letters. No need to go before the justice of the peace.
For landlords who wish to index correctly, our rental management page explains the procedure and calculations. Using a rental management software automates indexation and avoids this type of error.
What I learned
I overpaid 288 EUR over 4 months because I did not dare to check. Here are the lessons:
-
Never pay an increase without verifying it. The reflex: before paying the new amount, calculate the legal indexation on the FPS Economy website. If the requested amount exceeds the result, challenge it in writing before paying. Once you pay, the landlord can invoke tacit agreement.
-
Indexation is the only annual mechanism. During a lease, the landlord can only increase the rent through annual indexation (health index). Any other increase falls under triennial revision, which is subject to strict conditions of timing and justification.
-
Maintenance work is not value-adding work. A facade facelift, a like-for-like boiler replacement, a roof repair are maintenance work at the landlord’s expense. They do not justify a rent increase. Only work that significantly increases the rental value (insulation, extension, improved EPC) can support a revision.
-
Tenants’ unions are there for this. In Ghent, the Huurdersbond. In Brussels, the Syndicat des Locataires. In Wallonia, tenant advocacy associations. Free or low-cost consultations. They know the law and can help you draft the appropriate letter.
To understand your rent rights, see our comprehensive guide on rent in Belgium. If you are affected by an increase, also check the rules specific to your region on our lease page. More real-life situations in our tenant testimonies.
- “**Calculate your legal indexation yourself before paying.** The FPS Economy provides an official online calculator. Compare the amount requested by the landlord with the calculation result. A discrepancy = a potentially illegal increase.
- “**Never pay an increase without checking its legal basis.** Once you pay the new amount, the landlord can invoke tacit agreement. If in doubt, pay the old rent and send a letter challenging the increase.
- “**Rent revision mid-lease is strictly regulated.** Apart from annual indexation, the landlord can only request a revision in the last 3 months of each triennial period (3rd, 6th, 9th year), and only if circumstances have changed. Facade work does not automatically justify a rent increase.
Week-by-week timeline
Frequently asked questions
-
Indexation is the automatic annual adjustment based on the health index. It is calculated using a legal formula and cannot exceed the evolution of this index. Revision is a modification of the base rent, possible only in the last 3 months of each triennial period, if circumstances have changed (renovation, neighbourhood developments). These are two distinct mechanisms.
-
Yes, but only within the framework of a triennial revision and if the work significantly increases the rental value of the property (minimum 10% according to case law). The work must be substantial (energy renovation, extension) -- a simple facade facelift is generally not sufficient.
-
You can claim reimbursement of the overpayment by formal notice. Under Belgian law, paying an amount not owed does not constitute definitive acceptance. The limitation period is 5 years for rental claims. Send a registered letter with a detailed calculation.
-
The landlord must request it in writing. Indexation is not automatic. If the landlord forgets to claim it, they can do so retroactively but only for the last 3 months. They cannot claim indexation for the entire past period.
Manage all your leases in one tool
Lease generation, MyRent registration, payment tracking, digital inventory. 14-day free trial, no card required.