Rent indexation in Wallonia, September 2024
Your lease has its anniversary in September 2024? Here is the health index to use, the formula, and what Wallonia adds on top.
Which index for an anniversary in September 2024
Belgian law (Civil Code art. 1728bis) reads the health index of the month BEFORE the anniversary: for September 2024, that is August 2024. The starting index is the one of the month before the lease was signed.
No intermediate rounding: the ratio is applied in full, then the result is rounded to the cent.
| Lease signed in | Starting index | Rent from September 2024 | Since signature |
|---|---|---|---|
| September 2023 | 128.82 (August 2023) | €1,031.98 | +3.20 % |
| September 2022 | 123.68 (August 2022) | €1,074.87 | +7.49 % |
| September 2021 | 112.74 (August 2021) | €1,179.17 | +17.92 % |
| September 2020 | 110.20 (August 2020) | €1,206.35 | +20.64 % |
| September 2019 | 109.07 (August 2019) | €1,218.85 | +21.89 % |
Before any regional correction. A lease indexed every year lands on the same figure whatever the path: the ratio always runs from the starting index.
What Wallonia adds
Housing is regional. Three regions, three answers to the same question: does a poor energy certificate still weigh on the indexation of an older lease?
Between 01/11/2022 and 31/10/2023 Wallonia indexed PEB D at 75 %, E at 50 % and F/G not at all; since 01/11/2023 the base rent and base index are those of that capped year, so the lost share is never recovered (decree of 19 October 2022). Expressed as a factor on a full indexation, for a lease whose anniversary falls in this month:
Indexed in full, on the formula above. The only conditions left are the national ones: a registered lease, a certificate handed to the tenant, a written request.
Indexation is never automatic: it applies from your written request, and reaches back at most three months. An anniversary in September 2024 claimed late leaves money on the table for good.
An unregistered lease cannot be indexed, and neither can one whose tenant never received the energy certificate. Both are checked before the figure in the calculator.
Same month, other regions:
Figures as published by Statbel and read on September 30, 2026.
Your rent, your dates, the exact figure
The free calculator applies the formula, the regional correction and the three-month cap to your lease, and emails you the letter to send.
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