Rent and ISTAT Adjustments for Tenants in Italy

Rent updates (ISTAT) and local agreements (with attestation) 2 min read · published September 11, 2025

If you are a tenant in Italy and you received a notice of rent adjustment, this article clearly explains when and how an ISTAT adjustment or an increase tied to territorial agreements can be applied. You will find practical guidance to read the contract clause, calculate the adjustment amount, request the required certification and defend your rights in case of dispute. The article includes steps on registration, calculation methods, notice periods and useful documentation, with official references to verify the rules. The language is aimed at non-expert tenants, with concrete examples and practical tips to avoid common mistakes. Read the recommended steps to know how to proceed.

When and how to update the rent

The rent adjustment can only start if provided for in the lease contract or in territorial agreements; the matter is also regulated by housing lease rules and by agreed contracts[1]. ISTAT adjustments normally follow index variations and the percentage indicated in the contract: it is important to check the clause and the indicated deadlines.

Respond promptly to any disputes to avoid losing rights.
  • Check the adjustment clause in the contract and verify the indicated percentage.
  • Calculate the increase using the formula indicated (ISTAT or agreed percentage) before paying.
  • Ask the landlord for the certification of territorial agreements or the documentation justifying the increase.
Keep all rent receipts organized and stored safely.

Territorial agreements and certifications

Territorial agreements can set different criteria for adjustment compared to a simple ISTAT variation; if an agreement exists the landlord must provide the required certification. If you need to register or modify the contract registration use the RLI Form provided by the Italian Revenue Agency[2] and keep a copy of the registration.

In many cities, territorial agreements limit or set criteria for increases.

Key takeaways

  • Always check the deadlines indicated in the adjustment clause.
  • Calculate the increase before paying and compare it with the provided documentation.
  • Request the territorial agreement certification in writing if required.

FAQ

When can the landlord increase the rent?
The rent can be increased only if the adjustment clause is provided in the contract or if territorial agreements allow it.
How is the ISTAT adjustment calculated?
The contractual percentage is applied to the agreed base; often the percentage change of the ISTAT indices indicated in the contract is used.
What should I do if I don't receive the certification?
Request the certification in writing and keep all communications; if you do not receive a response you may contact the court or a tenants' protection association.

How to

  1. Read the contract clause and note the percentage and effective date.
  2. Calculate the increase: apply the indicated percentage to the base rent and compare the result with the landlord's request.
  3. Request the territorial agreement certification or documentation that justifies the increase in writing.
  4. If you receive no reply, contact a tenants' advocacy service or a lawyer to evaluate next steps.
  5. If necessary, prepare the documentation (contract, receipts, calculations) for any legal or administrative dispute.

Help and Support


  1. [1] Legge 431/1998 su Normattiva
  2. [2] Modello RLI e istruzioni su Agenzia delle Entrate
Bob Jones
Bob Jones

Editor & Researcher, Tenant Rights Italy

Bob writes and reviews tenant law content for various regions. They’re passionate about housing justice and simplifying legal protections for tenants everywhere.