How to Challenge an Illegal Rent Increase Through the RTB

24 July 2026

The RTB is your rent tribunal

The Residential Tenancies Board is the state body that adjudicates disputes between tenants and landlords. If you believe a rent increase is illegal, whether because it breaks the national rent cap (the lower of 2% or the general rate of inflation), ignores the 12 month rule, or was not properly served in writing, the RTB is where you challenge it.

The process is free, largely online, and heavily used. In 2024 the RTB received over 6,000 dispute applications, and rent-related disputes were the second largest category after deposits. This guide walks through exactly how to file one.

The 28 day deadline

You have 28 days from the date you receive the rent review notice to open a dispute. Miss this deadline and the increase is deemed accepted, even if it turns out to be unlawful. Diary the date the moment the notice arrives.

Step 1: gather your evidence

Before you file, put together:

- The rent review notice itself (photo or PDF). - Your existing lease and any previous rent review notices. - Proof of the current rent amount (bank statements showing standing orders work well). - If challenging on rent cap grounds: the date and amount of the last rent review and a calculation of the maximum lawful increase under the national cap. - If challenging on market rent grounds: three comparable current listings from Daft.ie or Property.ie, dated close to the review notice. - Any written correspondence with the landlord about the increase.

Save everything to a single folder on your phone or laptop. The RTB portal lets you upload documents; being organised now saves hours later.

Step 2: file the dispute application

Go to rtb.ie and choose Dispute Resolution. Create an account if you do not have one, then select the dispute type. For rent challenges, this is usually Validity of Notice of Rent Review or Rent More Than Market Rent.

You will be asked to:

- Enter the tenancy address and RTB registration number if you have it. - Describe the dispute in your own words. Keep it factual: dates, amounts, what rule you believe was broken. - Upload your evidence. - Choose mediation or adjudication.

Mediation is faster (typically 8 to 12 weeks) and involves an impartial mediator helping both sides reach agreement. Adjudication is more formal, evidence-based, and results in a binding determination order. For clear-cut illegal increases, adjudication tends to be more decisive.

Step 3: keep paying the current rent

While the dispute is open, keep paying your existing rent by the usual method. Do not start paying the new higher amount, and do not stop paying entirely. Both would weaken your case. Keep the standing order exactly as it was.

Step 4: the hearing

Adjudication hearings are usually held remotely by video call. You will present your case, the landlord will present theirs, and the adjudicator will ask questions. A typical hearing takes 45 to 90 minutes.

Tips for the day:

- Join from somewhere quiet with a stable connection. - Have all your evidence open in a separate window. - Speak calmly and stick to facts. Personal grievances about the landlord do not help. - If English is not your first language, you can request an interpreter in advance at no cost.

Step 5: the determination order

Within a few weeks of the hearing, the RTB will issue a written determination. If you win, the increase is invalid and the landlord cannot enforce it. If either party disagrees with the outcome, they have 21 days to appeal to the Tenancy Tribunal.

A determination order has the same legal weight as a court order. If the landlord ignores it (for example, by trying to evict you for challenging the rent), you can apply to the Circuit Court for enforcement.

What it costs

The RTB dispute process itself is free for tenants. You do not need a solicitor. The main cost is time: expect to spend perhaps 4 to 8 hours in total across preparation and the hearing.

Read next: our full guide on RPZ rules, or use the rent increase legality checker to sanity-check the numbers before you file.