Contractor with tax debts: how does the withholding obligation work and can you still pay the invoice?

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You have your office renovated, your premises cleaned, or your business secured. The invoice arrives and you simply want to pay for the services received. But with invoices from contractors in construction, cleaning, or security, you cannot just do that. You are legally required to first check whether they have debts with the tax authorities or social security.

If that is the case, you must pay a portion of the invoice directly to the government. This is called the withholding obligation (inhoudingsplicht/obligation de retenue), and in this article we explain everything you need to know so you are always compliant.

1. What is the withholding obligation and does it apply to me?

Suppose you hire a contractor to renovate your business premises. The work is done and the invoice is on the table. Normally you transfer the amount and that's that. But if that contractor has debts with the tax authorities or social security, the law obliges you to pay a portion of the invoice not to them, but directly to the government.

Sounds odd? Yet it has been the case in Belgium for years. And new since 1 May 2026: an additional category has been added — debts relating to self-employed social contributions (via the RSVZ/INASTI). So three categories in total to check.

2. Which sectors does this apply to?

You do not need to check every company you do business with for debts. The withholding obligation only applies when you have work carried out in these three sectors:

• Cleaning
• Construction & renovation
• Security and guarding
• Meat industry

In practice: a contractor renovating your shop, a cleaning company for your office, a painter finishing your site, a security firm for your event. Even if you yourself are a contractor and subcontract work to someone else, this applies to you.

The withholding obligation does not apply to private renovations. If you are a private individual having your own home renovated, you do not need to check or withhold anything.

3. I've received an invoice, now what?

Before you pay, you need to check whether the contractor in question has any debts. You do this twice:

• when signing the contract;
• and again just before paying the invoice.

Even if everything was in order at the start, debts may have arisen in the meantime.

How do you check whether a company has tax debts?

1. Go to Checkinhoudingsplicht

Visit Check inhoudingsplicht and enter the contractor's company registration number. You can find this on the quote, invoice, or in the CBE (enter the company name in Public Search).

2. Review the result

You immediately see whether there are debts and how much you need to withhold. No debts? Then simply pay the full amount. Debts? Then you can see exactly what percentage you must transfer separately.

3. Save the certificate

You can download a certificate as proof that you carried out the check. Keep this certificate together with the invoice. If an audit ever takes place, this is your protection.

4. How much do you need to withhold?

• 15% when the company or self-employed person has debts with the tax authority (FPS Finance).
• 35% when the contractor has debts with social security.
• NEW since 1 May 2026: 15% in the case of outstanding self-employed social contributions.

And a maximum of 50% when there are multiple debts.

These percentages are always calculated on the amount excluding VAT. You pay the VAT in full to your contractor as normal. That does not change.

5. How do you arrange the payment and what do you tell the contractor?

You make two payments:

1. the withheld portion goes to the government;
2. the remainder to the company or self-employed person.

Let your contractor know in advance. An unexpectedly lower amount arriving in their account without explanation only causes confusion.

A brief message might look like this:

"Hi [name], I have received your invoice and carried out the mandatory check via Checkinhoudingsplicht before paying. This shows that there are [tax / social security / RSVZ] debts. I am legally required to withhold [X]% and transfer it directly to [FPS Finance / NSSO / RSVZ]. I will transfer €[amount] to your account and €[withheld amount] to [the relevant body]. I will include the certificate as proof."

Example:

You receive an invoice for €2,000 excl. VAT (€2,420 incl. 21% VAT). The check shows your contractor has tax debts.

6. What if you forget?

As a business client, you can be held liable for the debts of your contractor or service provider. If you pay the invoice in full without checking, or fail to withhold when you should have, the government can come to you for your contractor's debts, and you may receive a fine.

That is also why the check matters before every payment, not just at the start. Everything was green when you signed the contract but you pay two months later? Check again. Debts can arise in between.

7. How do you process the withholding obligation in Accountable?

You have one invoice but two payments: one to your contractor and one to the government. In Accountable, you link both payments to the same invoice so everything balances correctly.

Don't worry, at Accountable we will help you remember: when you log an expense in a relevant category (construction, cleaning, or security), the expense form displays an info box with a link to Checkinhoudingsplicht, so you can verify whether any debts are outstanding before paying.

8. What if you yourself have tax debts?

If you work in construction, cleaning, or security and have outstanding tax or social contribution debts, your clients are obliged to withhold a portion of your invoice. You therefore receive less than invoiced, which can seriously disrupt your cash flow.

How do you know whether you have debts?

You can check your situation via the official portals:

• Tax debts: check MyMinfin. There you can see outstanding amounts and any repayment arrangements.
• Social security debts (NSSO): your social insurance fund can provide an overview, or consult the social security portal.
• Outstanding self-employed social contributions: log in to MijnRSVZ or the portal of your social insurance fund to see whether any quarters are outstanding.

Debt paid off but clients are still withholding? Contact the relevant body and request an update. Processing can sometimes take a few days. Once the system is updated, clients can pay you in full again.

Unable to pay everything at once? Both the RSVZ and FPS Finance offer repayment plans. Take the initiative and get in touch. The sooner your debts are cleared, the sooner your clients can pay you in full again.

When in doubt, always consult an accountant or tax adviser.

Author - Valesca Wilms

As content marketing lead at Accountable Belgium, Valesca writes about freelancing, self-employment, and taxes based on her own experience as a freelancer.

Who is Valesca ?