Duty of care for subcontractors in Flanders: what applies from 16 October 2026

The duty of care (zorgvuldigheidsplicht) means that a business working in Flanders with a direct subcontractor from a risk sector, such as construction, collects certain residence and work documents before work starts, checks them, keeps them for five years and reports gaps. Since 16 October 2026, no passport is needed and works below the Declaration of Works thresholds are excluded.

What changed on 16 October 2026?

A Flemish Government decree of 4 September 2026, published in the Belgian Official Gazette on 6 October 2026, has applied since 16 October 2026. It makes three changes:

What to do now: take the passport off your own checklist and subcontract templates, and check for each site whether the Declaration of Works applies.

At a glance

• Does it apply to your site? Only for works in Flanders, with a direct subcontractor from a risk sector, and in construction only when the works fall under the Declaration of Works.
• Which documents? Proof of residence, proof of a work permit or professional card, and Limosa, A1 or Dimona depending on the situation. No passport.
• Something missing? Ask your subcontractor. If they don't respond, report it through the Flemish Social Inspectorate's online reporting office.

This article is for information only and is not legal advice.

Who this applies to

These rules come from the Flemish Region, but they are not only for Flemish companies. They apply to any Belgian or foreign business directly or indirectly involved in activities carried out in Flanders. What matters is where the work happens, not where you are registered. A contractor from the Netherlands, Poland, Wallonia or Brussels working on a site in Antwerp or Ghent is covered, and so is the Flemish main contractor who brings them in.

If you have come across "chain liability" in a Dutch tax context (the Netherlands' Belastingdienst), note that this is a different scheme. This article covers the Belgian, Flemish rules on illegal employment.

What is chain liability for illegal employment?

Chain liability means every link in the contracting chain can be held liable when third-country nationals who are staying illegally are put to work as employees or self-employed persons. That covers the principal (the client), the main contractor and any intermediate contractor. Third-country nationals are people who are not nationals of an EEA country or Switzerland.

Direct and indirect subcontractors

• Direct relationship: you appointed the (sub)contractor yourself. If they employ third-country nationals staying illegally, you can be held liable unless you meet the conditions below.
• Indirect relationship: this is your subcontractor's subcontractor. You are only liable if the inspection services show you knew in advance.

Anyone who knew in advance is liable regardless of their place in the chain.

Private clients

A private individual who commissions work is only liable if the inspection services show they knew in advance. The written declaration and the duty of care do not apply to them, which is useful to know when a homeowner asks you about it.

Not the same as the withholding obligation

The duty of care is about the residence and work status of the people your subcontractor deploys. The federal withholding obligation (30bis) is about your subcontractor's social security and tax debts and what you withhold from your payments. They are separate obligations; see our article on withholding checks when paying subcontractors.

Written declaration and duty of care: what you need to do

What you need to rule out liability depends on the sector of your direct subcontractor:

• Not a risk sector: you need a written declaration in which the subcontractor confirms they do not and will not employ third-country nationals staying illegally, either as employees or as self-employed persons. The duty of care does not apply.
• Risk sector: you need that written declaration and you comply with the duty of care: have the documents provided, check them, keep them and report what is missing.

Is the duty of care mandatory?

According to the Flemish authorities, complying with the duty of care is not mandatory, but strongly recommended. You may choose not to ask for anything. But if your direct subcontractor is then caught employing third-country nationals staying illegally, you are liable and risk criminal prosecution or an administrative fine.

Since when?

The duty of care has applied since 1 January 2026. A six-month grace period ended on 1 July 2026, and sanctions have been possible since then. The three relaxations apply from 16 October 2026.

Does the duty of care apply to my site?

Work through these four questions for each site and each direct subcontractor.

1. Is the work carried out in the Flemish Region?

If not, these Flemish rules do not apply. They cover work carried out in Flanders.

2. Is your direct subcontractor active in a risk sector?

The risk sectors are:

• construction: works on immovable property and supply of ready-mixed concrete;
• cleaning;
• meat: slaughtering, cutting and meat preparation;
• parcel delivery on behalf of postal services, except deliveries made with a vehicle subject to tachograph rules.

3. Do the works fall under the Declaration of Works?

This is the new question from 16 October 2026. Works on immovable property, including cleaning, are only a risk activity if they are subject to the Declaration of Works under Article 30bis §7 of the RSZ/ONSS Act of 27 June 1969. The Flemish Government did this to align the scope with the existing Declaration of Works, at the request of the social partners.

When is a Declaration of Works required? The NSSO (RSZ/ONSS) frames the rule as an exception: the duty to declare does not apply to

• a contractor without a subcontractor, for works totalling less than €30,000 excluding VAT;
• a contractor with one, and only one, subcontractor, for works under €5,000 excluding VAT.

In every other case, a declaration is required. With two or more subcontractors, the €5,000 limit therefore does not apply: in the NSSO's example, a €3,000 contract with two subcontractors must be declared. The €3,000 is an example, not a separate threshold; the NSSO gives no minimum amount once there are two or more subcontractors.

(Amounts and "declare yes/no" taken from the NSSO example. "Yes" in the last column means the works are a risk activity; whether you need documents still depends on question 4.)

Flanders.be words the exception to the duty of care the same way: it does not apply to construction or cleaning works under €30,000 excluding VAT without a subcontractor, or under €5,000 excluding VAT with only one subcontractor. Below those limits, you still need the written declaration.

Asbestos: according to the NSSO, works that are hazardous because of asbestos must also be indicated in the declaration, and asbestos removal works must be declared at least 15 calendar days in advance. The NSSO does not say that asbestos works below the amounts above become declarable for that reason. If in doubt on a small job involving asbestos, check with the NSSO or the Flemish Social Inspectorate.

Check again if the contract value or the subcontracting chain changes during the job. If you are a foreign contractor, read what you need before filing a Declaration of Works as a foreign contractor.

4. Does your direct subcontractor deploy third-country nationals?

The document list below is about third-country nationals: employees or self-employed persons who are not nationals of an EEA country or Switzerland. For them, it has to be checked that they are staying and working legally. You need the written declaration in every case.

Which documents to request

Your direct subcontractor provides the documents. Which ones depends on the employment situation. The list below follows the Belgian Dutch and French texts: the decree as published in the Belgian Official Gazette and the official Flanders.be guidance.

Posting from an EEA country or Switzerland

• proof of the right of residence or a residence permit for more than three months in the EEA Member State or Switzerland where the foreign worker or self-employed person lives;
• proof of registration in the Limosa database, unless an exemption from the Limosa reporting duty applies;
• the A1 certificate confirming that the person is covered by the social security system of the Member State they are posted from. The acknowledgement of receipt of the application is also accepted.

Posting from outside the EEA or Switzerland, where a Belgian work permit or professional card is required

• proof of valid residence in Belgium or a single permit;
• proof of a valid Belgian work permit or single permit (employees), or of a valid professional card (self-employed);
• proof of registration in the Limosa database, unless an exemption applies.

Employment in Belgium

• proof of valid residence in Belgium or a single permit;
• proof of a valid Belgian work permit or single permit (employees), or of a valid professional card (self-employed);
• proof of registration in the Dimona database (employees only).

Not sure which posting document covers what? See A1 certificate or Limosa and, for self-employed workers, professional card or Limosa.

What is no longer on the list

The passport or travel document has been removed. The Flemish Government explains that not everyone who may legally work can show a passport, asylum seekers whose application is still pending being one example. Requiring it led to confusion and unnecessary reports.

When?

The documents must be in place before the work begins.

Check, keep and report

Check

You do not have to judge whether documents are authentic. You do check that they are not obvious forgeries, and you check the expiry date. A blatant forgery or an invalid document counts as a missing document.

Keep, and handle personal data carefully

Keep the documents for five years after the collaboration ends, available to the inspection services. Because these are personal data, Flanders.be asks you to:

• request or share only the listed documents;
• store them securely, accessible only to authorised people;
• use them only for chain liability purposes.

Your direct subcontractor may pass copies to the principal, or to the contractor one level up in the chain; the rules provide a legal basis for this. The Flemish authorities also recommend agreeing in the contract who informs the workers concerned about the processing of their data (Articles 13 and 14 GDPR).

Report through the reporting office

A document missing, clearly forged or invalid? First ask your subcontractor for the correct documents. If they do not respond, report it to the Flemish Social Inspectorate (Vlaamse Sociale Inspectie) through the online reporting office. Only then have you met the duty of care.

Sort out access in advance:

• you log in with itsme or eID on behalf of your company, not as a private individual;
• you need the right user permissions, granted by your company's access manager;
• your company must be registered with the NSSO (RSZ/ONSS);
• a social secretariat or other social service provider cannot currently file a report on your behalf;
• a foreign company without a Belgian enterprise number (KBO/BCE) requests a PDF form from [email protected] and returns it by email.

Site checklist for the main contractor

• Is the work in the Flemish Region?
• Did you appoint the subcontractor directly?
• Do you have your direct subcontractor's written declaration?
• Are they in a risk sector (construction, cleaning, meat, parcel delivery)?
• Do the works fall under the Declaration of Works? Note: with two or more subcontractors there is no minimum amount. Recheck if the value or chain changes.
• Does the subcontractor deploy third-country nationals, and in which situation: posting from the EEA, posting from outside the EEA, or employment in Belgium?
• Do you have the right documents before the start, without a passport?
• No obvious forgery, expiry dates checked?
• Anything missing: subcontractor asked and, without a response, reported through the reporting office?
• Is your access to the reporting office set up?
• Are documents stored securely, for authorised people only, until five years after the collaboration?
• Has the passport been removed from your own checklist and contract template?

Keeping track without extra folders

The duty of care adds to what you already track per subcontractor: the Declaration of Works, Limosa, insurance and contracts. It helps to keep those documents with the site they belong to rather than in separate inboxes and folders. Our article on a pre-start check on subcontractor evidence shows the same principle for insurance.

With Enfin construction software, you plan work and keep documents and registrations with the right project. Alfie, the AI colleague in Enfin, monitors projects with you and tells you when something needs attention; you decide what happens next. For the bigger picture, read our guide to managing subcontractors on Belgian sites.

Frequently asked questions

Do I still need to ask my subcontractor for a passport?

No. Since 16 October 2026, the passport or travel document is no longer one of the documents your direct subcontractor has to provide. The other documents are still needed, depending on the situation: proof of residence, a work permit or professional card, and Limosa, A1 or Dimona.

Does the duty of care apply to small jobs?

Not if the works do not fall under the Declaration of Works. According to Flanders.be, it does not apply to construction or cleaning works under €30,000 excluding VAT without a subcontractor, or under €5,000 excluding VAT with only one subcontractor. With two or more subcontractors there is no minimum amount: a Declaration of Works is always required. You still need the written declaration to rule out liability.

Which documents should I request from a subcontractor?

It depends on the third-country national's situation. Posting from the EEA: proof of residence of more than three months, Limosa and A1. Posting from outside the EEA: Belgian residence or single permit, work permit or professional card, and Limosa. Employment in Belgium: residence or single permit, work permit or professional card, and Dimona for employees.

What if my subcontractor does not provide the documents?

Ask them for the correct documents first. If they do not respond, report it through the Flemish Social Inspectorate's online reporting office. That report is what completes your duty of care. You log in with itsme or eID on behalf of your company, with the right permissions.

How long do I need to keep the documents?

For five years after the collaboration ends, so the inspection services can consult them. Request only the listed documents, store them securely and limit access to authorised people in your company.

Am I liable for my subcontractor's subcontractor?

Only if the inspection services show that you knew in advance that third-country nationals staying illegally were being employed. The written declaration and the duty of care concern your direct subcontractors, the ones you appoint yourself.

Is the duty of care mandatory?

According to the Flemish authorities, it is not mandatory but strongly recommended. If you request nothing and your direct subcontractor is caught employing third-country nationals staying illegally, you are liable and risk criminal prosecution or an administrative fine.

Does it also apply in Brussels and Wallonia?

These Flemish rules cover activities in the Flemish Region, even if your company is based in Brussels, Wallonia or abroad. They do not cover sites in Brussels or Wallonia; check the rules that apply there separately.

Sources and verification

Checked on 21 October 2026.

• Flemish Government Decree of 4 September 2026, Belgian Official Gazette of 6 October 2026 (numac 2026007053): copy on etaamb (Dutch)
• Flemish Government, decision of 4 September 2026 (Dutch)
• Flanders.be, Chain liability for illegal employment
• NSSO, Bericht aan de aannemers en opdrachtgevers (Dutch, PDF) / Avis aux entrepreneurs et commettants (French, PDF)
• NSSO, Déclaration de travaux (French) / Aangifte van werken (Dutch)
• KMO.partners, Vlaamse ketenaansprakelijkheid versoepeld (Dutch) (19 October 2026)

This article is for information only and is not legal advice. The official rules are published on Flanders.be. Questions can go to the Flemish Social Inspectorate at [email protected].