RentWise Team: A rent increase must generally be notified in writing, using the required rent review notice, and the landlord must send the notice to the tenant and the RTB on the same day. It should state the new rent, the date it starts, the required calculation or supporting market-rent information, and the tenant’s right to refer a dispute to the RTB. The notice must normally be served at least 90 days before the increase takes effect, although the applicable rules can depend on the tenancy and date. Check the latest RTB template and guidance, or ask a solicitor if the notice or calculation is unclear.