Historically, an area could be designated as an RPZ where its standardised average rent was above the national average and annual rent inflation was 7% or more in at least four of the previous six quarters. Designations were based on Residential Tenancies Board data and made under the relevant tenancy legislation. Since 1 March 2026, national rent-control rules have replaced the RPZ system for most new and existing tenancies, so the current rent-increase rules should be checked on the official government or RTB website. Individual cases may depend on the tenancy’s dates and circumstances.