For a tenancy covered by Rent Pressure Zone rules, a landlord generally must give written rent review notice at least 90 days before the new rent takes effect and send a copy to the RTB on the same day. The notice should state the new rent, the effective date, the calculation used and other information required by the RTB. Rent can generally be reviewed no more than once every 12 months. Check the RTB’s current guidance and calculator, as the applicable rules can depend on the tenancy and date; any dispute about validity is ultimately decided through the RTB process.