Rent indexation calculator for Wallonia
Calculation compliant with article 26 of the Walloon decree of 15 March 2018 on residential leases. The EPC limitation period ended on 31 October 2023, but a special calculation method remains for the leases concerned, rated EPC D to G or without a certificate (decree of 19/10/2022).
A few details.
The calculation from your data.
Property region, lease dates, initial rent, EPC class. The calculation runs instantly.
The Walloon legal context in 2026
Wallonia has gone through two successive phases regarding rent indexation:
- 1 November 2022 — 31 October 2023: limitation of indexation for energy-inefficient properties (decree of 19 October 2022) — EPC A to C: 100%; D: 75% of the increase; E: 50%; F, G and no certificate: no indexation.
- Since 1 November 2023: end of that period — special calculation method for leases rated EPC D to G or without a certificate that had an anniversary in it (same decree, still in force), ordinary formula at 100% for the others.
Concretely, in 2026, the indexation calculation for a Walloon rent follows the ordinary formula for most leases. Those limited in 2022-2023 start from the adapted rent of that period, with the index of the month preceding the anniversary that fell within the period as starting index — until the end of the tenancy, unless a favourable label is obtained after renovation (Constitutional Court, ruling no. 64/2024 of 20 June 2024). The calculator identifies the right regime from three inputs: signature date, effective start date and EPC.
Historical EPC coefficients (reference)
D-G or no-certificate leases with an anniversary in the 11/2022-10/2023 window: indexation computed from the window's adapted rent (decree of 19/10/2022). Other leases: 100%.
The table summarises the current regime. The percentages of the period that ended on 31 October 2023 (D: 75%, E: 50%, F-G and no certificate: 0%) no longer apply as such: for the leases concerned, they set the adapted rent that serves as the basis for the special calculation method.
Conditions to be met
- Written, registered lease
- Written request to the tenant (simple letter or registered mail)
- One indexation per year, at the earliest on the anniversary of the effective start date
- Starting index: month preceding the signature; new index: month preceding the anniversary
- Retroactivity limit: 3 months (art. 57)
- The EPC certificate is not a general condition for indexing in Wallonia
Frequently asked questions — Wallonia
Does the EPC still apply in Wallonia in 2026? + −
Yes, for certain leases. The limitation period ended on 31 October 2023, but the decree of 19 October 2022 (still in force) provides a special calculation method for leases that took effect before 1 November 2022, rated EPC D to G or without a certificate, and that had an anniversary between 1 November 2022 and 31 October 2023: indexation starts from the adapted rent of that period, until the end of the tenancy. Other leases follow the ordinary formula, at 100%.
Which legislation governs indexation in Wallonia? + −
Article 26 of the Walloon decree of 15 March 2018 on residential leases, as amended by the decree of 19 October 2022 (Belgian Official Gazette of 3 November 2022), which has not been repealed. Article 57 of the same decree limits retroactivity to three months. The Walloon Public Service (SPW) publishes the procedure on wallonie.be.
My Walloon lease was signed in 2022 with EPC F: what happens? + −
It all depends on the effective start date. If the lease took effect before 1 November 2022, its first anniversary fell within the limitation period (1 November 2022 → 31 October 2023), when an EPC F property could not be indexed: it has since fallen under the special calculation method. Example: €700, signed on 10 February 2022, effective 1 March 2022 — adapted rent on 1 March 2023: €700.00 (instead of €751.22); on 1 March 2026: 700 × 138.06 ÷ 126.86 = €761.80 (instead of €817.55 with the ordinary formula). If the lease took effect on or after 1 November 2022, the ordinary formula applies at 100%. The calculator chooses automatically.
On what date does indexation take effect? + −
At the earliest on the anniversary of the lease's effective start date. The signature date is used to determine the starting index (month preceding the conclusion of the lease). You must request the indexation from the tenant in writing — a simple letter is sufficient, but we recommend registered mail to keep proof.
How many months of arrears can I recover? + −
Three months maximum: those preceding the month of your written request (art. 57 of the decree of 15 March 2018). For earlier months, the unclaimed indexation is lost, even if the lease is valid and the calculation correct.