Rent indexation

As a landlord, being able to index your tenants’ rent each year is highly beneficial. As a general rule, the index is always positive because it tracks the cost of living. But what conditions must be met to index the rent? What happens if your tenancy agreement is not registered or if you have never applied indexation? 

If, as a landlord, you have not registered the tenancy agreement

Wallonia is the strictest region on this issue: if the tenancy agreement is not registered, you cannot index the rent.

In practical terms, this means that if you index the rent and the tenant complains, you are in the wrong and the indexation applied is invalid.

In Flanders and Brussels, however, even if the tenancy agreement is not registered (although this is theoretically compulsory!), you cannot be faulted for having indexed the rent, and the indexation remains valid.

If, as a landlord, you have never applied indexation, can you index the rent during the term of the tenancy?

Yes, you are entitled to do so, and the tenant cannot challenge it; they must consider the years without indexation to have been granted to them. However, the difference in rent can sometimes be quite significant if no indexation has been applied for several years.

To notify the tenant of the indexation, there is no need to use registered post; a simple letter is sufficient provided that the request is made in writing (be careful with emails, whose legal validity may be disputed depending on the judge). If you know that your relationship with your tenant is not particularly good, it is preferable to send the request by registered post to ensure that you have the necessary evidence.

If, as a landlord, you have forgotten to apply indexation during the year

You are entitled to claim the difference, but only for the three months preceding the request, which must be made in writing.

Therefore, if you make the request in June, the tenant owes the indexation for March, April and May, as well as for the months following June.

How is the indexation calculated?

The request may be made no earlier than the anniversary date of the tenancy agreement. However, this does not prevent the landlord from requesting indexation after that date.

Indexed rent = (basic rent * new index) / starting index

The basic rent is the rent agreed when the tenancy agreement was signed (excluding charges)

The starting index is the index for the month preceding the signing of the tenancy agreement (it is indeed the date on which the tenancy agreement was signed and not the date on which the tenancy agreement took effect)

The new index is the health index for the month preceding the anniversary of the date on which thetenancy agreement took effect (so, in this case, not the date of signing, but the date on which the tenant actually moved into the property).

Do not worry, you will find an online calculation tool here