In Belgium

A joint surety is a legal mechanism where a third party (parent, friend, employer) commits to paying the tenant’s debts upon default. It differs from the rental guarantee (blocked account): it is a personal commitment, not a deposited sum.

The “joint” aspect means the landlord can pursue the guarantor directly for payment, without first having to pursue the tenant.

The surety is not governed by regional rental legislation — it falls under general obligations law. The landlord can request it as a supplement to the rental guarantee but cannot require it as a replacement.

The guarantor can limit their commitment in time (e.g. the first 3 years) or amount (e.g. maximum 6 months’ rent).

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Warning
Without written limitation, the joint surety covers all the tenant’s debts for the entire lease duration, including renewals. An uninformed guarantor could find themselves committed for 9 years.

Practical example

Thibault, a student with no income, rents a room in Leuven. The landlord requests a joint surety from a parent in addition to the 2-month guarantee. Thibault’s father signs a surety deed for a maximum of 3,000 EUR. If Thibault accumulates 2 months’ rent arrears, the landlord can claim payment directly from the father.