If you believe a rent increase breaches the Rent Pressure Zone (RPZ) rules, you can refer the dispute to the Residential Tenancies Board (RTB). Check whether the property was in an RPZ when the notice was served, whether the rent review timing and increase limit were followed, and whether the notice included the required information. Keep the notice, tenancy agreement, payment records and relevant correspondence, and check the RTB’s current time limits before applying for mediation or adjudication. The RTB will assess the individual facts, so consider getting advice from a solicitor or Threshold if the issue is complex.