How do you challenge an illegal rent increase?

In the 2026 Dutch housing market, the rules concerning rents are stricter than ever. With the full implementation of the Affordable Rent Act and the annual setting of maximum increase rates, tenants in all segments, social, middle rent and the free sector, have powerful legal means to defend themselves against excessive price increases. Nevertheless, landlords regularly try to push the boundaries, hoping that tenants are not aware of their rights.

Combating an illegal rent increase requires a structured approach. In this article, we explain how to check whether an increase is unlawful in 2026 and what steps you need to take to successfully challenge it.

Check the 2026 legal ceilings

The first step is to verify the percentage proposed by the landlord. In 2026, the permitted increases are legally linked to inflation or the collective labor agreement wage development, depending on the type of home you rent.

For the year 2026, the following maximum percentages apply:

• Free sector: Maximum 4.4% (based on inflation + 1%).
• Middle rent: Maximum 6.1% (based on wage development + 1%).
• Social rent: Maximum 4.1% from July 1, 2026 (for rentals above €350).

If the landlord's proposal exceeds these percentages, the increase is basically illegal. Note: is there a lower percentage agreed in your rental contract? Then that lower percentage is leading. Here, the law acts as a “ceiling”, not as a standard that can overrule contractual agreements.

Assess procedural requirements

A rent increase is not only illegal if the amount is too high, but also if the landlord does not comply with the formal rules. In 2026, an increase proposal must meet strict requirements to be valid.

• The announcement period: For social housing, you must make a minimum of the proposal, two months received in writing before the commencement date. Will you only receive the letter in June for an increase as of 1 July? Then you can refuse the increase or have it postponed.
• Frequency: In principle, the rent may only be increased once every twelve months. There are exceptions, such as after a major renovation of the home, but the annual indexation is strictly limited to one moment per year.
• Content of the proposal: The proposal must include the old rental price, the new rental price, the percentage of the increase and the effective date. It must also be clearly stated how you can object.

Objecting to the landlord

If you have determined that the increase is unlawful, the next step is to file a formal appeal with the landlord. Always do this before the date the increase should take effect.

In your appeal letter, you specifically state why you do not agree. This may be because the percentage is above the legal maximum, because the home has serious maintenance defects (which could be a reason for rent freezing), or because the announcement was too late. To do this, you can use model letters from the Legal Counter or the Housing Association. In 2026, it is also advisable to check whether your home falls into the right segment; if a home should actually be social rent due to the points system (WAS), but if a free sector is rented out, the increase is often immediately questionable.

Involve the rent commission

If the landlord rejects your objection or does not respond, you don't have to pay the increase just like that. The procedure will vary slightly by sector in 2026, but the essence remains that an independent party must judge.

• Social rent: If you have objected in writing, the landlord must go to the Rental Committee within six weeks of the commencement date to have the increase reviewed. Does the landlord not do this? Then the increase expires automatically.
• Free sector and middle rent: Here you often have to take action yourself. If you cannot reach an agreement with the landlord, you can ask the Rental Commission to rule on the reasonableness of the increase. You must do this within four months of the proposed start date.

The decision of the Rental Committee is binding. If the increase turns out to be illegal, the rent will be set at the legally permitted level or even frozen.

What to do in the event of a “Tacit” objection?

A risky but effective method in 2026 is not paying the increase (while continuing to pay the old rent). This is seen as a form of objection. The landlord must then send you a registered reminder letter (reminder letter) within three months of the commencement date.

If you receive this reminder, you will have one more month from that moment to still engage the Rent Commission. If the reminder is not sent or sent too late, the rent increase has not been legally concluded. Please note: this route requires nerves of steel and good administration, as in case of error, you will still have to pay the increase retroactively, including any procedural costs of €25.

Exception: Rent increase after home improvement

It is important to know that landlords may increase the rent additionally in 2026 after improvements to the home, such as insulation, a new kitchen or solar panels. This is independent of the annual rent increase.

However, this increase is only legal if the improvements lead to greater home comfort and if you, as a tenant, have agreed in writing to both the work and the associated rent increase in advance. A landlord should never use regular maintenance (such as painting windows or repairing a leak) as a reason for a rent increase. If this does happen, it is an immediate reason for a successful challenge with the Rent Committee.

By staying alert to the percentages and the procedural rules, you avoid paying too much each month. In 2026, the law will stand firmly on the side of the well-informed tenant