A Rent Pressure Zone (RPZ) is an area where rent increases are restricted by law, rather than being set entirely by the open market. Generally, a landlord may increase rent only at permitted intervals and within the applicable statutory limit, although exemptions and special rules can apply. Whether a property is covered depends on its location, tenancy circumstances and the rules in force when the increase is proposed. Check the latest guidance and RPZ information on the official government or RTB websites, and seek professional advice if you believe an increase may be unlawful.