Short answer: yes, once every 12 months, by a small amount, with 90 days’ written notice. The long answer is where landlords make expensive mistakes and tenants leave money on the table. Here it is, as the law stands after 1 March 2026 (Residential Tenancies Act 2004 as amended; the RTB’s own summary is at setting and reviewing private rents).
Once in 12 months
A rent review may not happen more often than once every 12 months, counted from the start of the tenancy or from the last review (section 20(1)). The one exception is a substantial change in the nature of the accommodation, which resets the clock (section 20(3)). Outside the Rent Pressure Zones the gap used to be 24 months; section 20B switched that off for tenancies created on or after 1 March 2026. It survives only for older tenancies in the 54 areas that became Rent Pressure Zones on 20 June 2025, where a rent set before that date can be reviewed for the first time 24 months after it was set.
The review date is the date the notice is served, not the date the new rent starts. So a landlord who served a notice on 1 June 2026 can serve the next on 1 June 2027, with the new rent taking effect 90 days later.
The cap: 2% a year or inflation, whichever is lower
Since 1 March 2026 the same limit applies to every private tenancy in Ireland (section 19(4)). The new rent may not exceed the old one by more than 2% per year pro rata since the rent was last set, and may not exceed it by more than the change in the CSO Consumer Price Index over the same months. The lower of the two wins. Twelve months of 1.4% inflation means a 1.4% cap. Twelve months of 3% inflation means 2%.
Two things sit above that arithmetic. The rent may never be above market rent, at the start and at every review (section 19(1) and (2)). And the review notice must prove it: three comparable tenancies from the public Rent Register with their RT numbers, similar in floor area, bedrooms, type and BER, in a comparable area (section 22(2A)). A notice without them is void.
One class of home escapes the 2%: apartments in a development whose commencement notice was lodged on or after 10 June 2025. There the cap is inflation alone (section 19(4)(aa)). Houses do not qualify, and market rent still binds.
The 90 days and the copy to the RTB
The notice must be in writing, on the RTB’s form (guide and download) or with the same contents, and give at least 90 days before the new rent takes effect (section 22(2)). Since 14 September 2026 the landlord has 7 days from serving the tenant to lodge a copy with the RTB; before that, from 28 February 2026, it had to go the same day. Without the copy the notice is not validly served, the increase does not take effect, and after two letters the RTB can issue a €200 fixed payment notice (section 22(4) to (7)). Email counts as service since 1 March 2026 if the tenant uses that address and the landlord keeps a record of sending (section 6(1)(ca)).
The tenant then has until the new rent starts, or 28 days from receiving the notice if that is later, to dispute the figure at the RTB (section 22(3)). An invalid notice can be challenged at any time.
Between tenants: the cap follows the home
The rule that surprises most landlords is that the cap does not end with the tenancy. If the last tenancy ended within two years, the new tenant’s rent is the old rent plus the cap for the months in between (section 19(4)(c)). A landlord who ends a tenancy to sell, or for a family member, and then lets again inherits the old rent. Market rent is allowed only in the cases listed in section 19(5): no tenancy for two years (one for a protected structure); the last tenant left by their own notice; the landlord ended the tenancy for breach, unpaid rent after a warning, or because the home no longer suited the tenant, with that ground stated on the notice of termination; or a substantial change to the home. Tenancies created from 1 March 2026 also get a reset to market rent after six lawful years, so the first of those falls in March 2032.
Every one of those exceptions needs a Notice of Exemption to the RTB and to the tenant within a month of setting the rent (section 19(5B)). A false exemption is a rent above the limit, which is a €200 fixed payment notice from the RTB and, for the tenant, a refund of the excess.
What a landlord should do each year
- Check the date the rent was last set. Twelve months must have passed since then, not since the last increase took effect.
- Run the calculation on the RTB calculator or ours, with the exact dates. Keep the printout: the notice has to show the CPI figures.
- Open the Rent Register for the local electoral area and pick three new lettings of homes like yours: size, bedrooms, type, BER. Their rents have to support the figure you are asking. If the register says similar homes let for less, the cap is not your ceiling, the market is.
- Serve the notice with 90 days’ notice, lodge the copy with the RTB within 7 days, and update the registration within a month of the new rent starting (section 139).
What a tenant should do
- Count the months since the rent was last set and check the arithmetic against the calculator.
- Look up the three RT numbers on the register. A notice that leans on bigger or better homes is a notice you can argue with.
- Ask the RTB whether the copy arrived. No copy, no increase.
- If the figure is wrong, apply to the RTB before the 28 days run out. Adjudication costs €30; mediation is free. How a rent dispute works.