Construction work and similar services: check for withholding requirements before paying your invoices

When a company or self-employed individual hires a contractor for certain work or services, a specific requirement may apply: the withholding requirement. This rule aims to combat tax and social security debts in certain sensitive sectors and requires the client to verify the contractor’s status before making any payment.

If the client fails to verify or withhold payment when required, they may be held jointly liable for their contractor’s tax or social security debts. The financial risk is therefore far from negligible.

General Principle

Before paying an invoice related to certain activities, the company or self-employed individual commissioning the work must verify whether the contractor has any tax or social security debts.

If debts exist:

• the client may not pay the full amount of the invoice;
• the client must withhold a portion of the amount excluding VAT;
• this sum must then be paid directly to the relevant tax authority.

If this obligation is not met, the client may be required to pay all or part of the invoice a second time, in addition to any potential surcharges.

Covered Activities

The withholding obligation applies primarily to four sectors:

1. Construction

This includes, in particular:

• construction
• renovation
• remodeling
• demolition
• maintenance and cleaning

Common examples:

painting, electrical work, plumbing, heating, air conditioning, fire protection, carpentry, flooring installation, technical maintenance, or landscaping.

• Security and surveillance

Certain activities falling under Joint Commission 317, such as building security or access control at events.

• Meat sector
• Delivery of ready-mix concrete

Who is affected?

The requirement applies to:

• self-employed individuals
• companies
• contractors
• clients

Whenever the work involves a property used for business purposes.

It applies in particular when:

• work is performed in a store or office;
• work involves the business portion of a residence;
• work is performed in a mixed-use building;
• a contractor subcontracts all or part of their work.

Each contractor is then liable to their subcontractor.

Amount of the withholding

The withholding is calculated on the pre-tax amount of the invoice.

In the event of tax debts:

→ 15% pre-tax withholding to be paid to the FPS Finance.

In the event of social security (ONSS) debts:

→ a 35% withholding (excluding VAT) to be paid to the ONSS.

Since 2026, a 15% withholding (excluding VAT) may also apply for social security debts of self-employed individuals, to be paid to the INASTI.

In the event of both tax and social security debts, the withholding may reach 50% of the amount excluding VAT.

Mandatory verification before each payment

Verification must be performed before each payment, including for down payments.

This is done through the official app:

Simply enter the contractor’s business number. The system will then indicate:

• green: no withholding required;
• red: withholding required.

If no withholding is due, it is recommended to generate and retain the verification certificate along with the invoice.