Checkinatwork and subcontractors: who registers whom?
As a contractor you are responsible for the registration of your own people and of your subcontractors and their employees. Here you can read who has to do what, according to the NSSO (RSZ/ONSS) and the law.
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Who registers the subcontractors?
The contractor. As an employer or contractor you must make sure that your employees, your subcontractors and the employees of your subcontractors are registered (NSSO, who it is for).
You can do that in two ways:
- you register yourself
- you clearly agree that the employee or subcontractor registers themselves. In that case you have to give them a means of registration. That may also be the NSSO’s online service.
Do I have to check whether my subcontractor registers?
Yes. A contractor that engages a subcontractor must take measures so that the subcontractor actually and correctly registers and forwards all data. Whoever does not do so commits an offence themselves (NSSO, responsibilities and sanctions). Read what that can cost on our page about fines.
How do subcontractors know they have to register?
The contractor that declared the works must provide the necessary information to all parties involved. That can be done, among other ways, with a poster with a QR code on the site. The NSSO makes that poster available (NSSO, works on immovable property).
The sites where registration is mandatory must also be declared in the declaration of works (NSSO, Checkinatwork).
Does it also apply to self-employed subcontractors?
Yes. Self-employed persons who carry out works on immovable property as a subcontractor must be registered. The rules for employees apply to them as well. They agree with their principal who registers (NSSO, who it is for).
And temporary agency workers?
For the declaration of works, the temporary work agency is a subcontractor of the company that uses the agency worker. That company registers the attendance of the agency worker (NSSO, who it is for).
What changes with CIAO?
With CIAO, every contractor and every subcontractor must take the necessary measures so that everyone who enters the construction site on its behalf can register before entering or leaving the site. That is laid down in the programme law of 30 May 2026 (title 6, chapter 1, art. 124 to 131).
Frequently asked questions
As the main contractor, do I have to follow up the whole chain?
The NSSO writes that the declaring contractor remains responsible for its chain of subcontractors. That sentence appears in the rules for sites with cleaning works (NSSO, works on immovable property).
Can an app do the registration for my subcontractors?
Yes, as long as the registration reaches the NSSO. See which tools do that automatically in our comparison of Checkinatwork apps.