ISTAT Increase and Rent: 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 wondering who pays an ISTAT adjustment to the rent, this guide clearly explains practical principles, tenant rights and possible actions. You will find examples on how to read the adjustment clause in the lease, when an increase is automatic or requires a territorial agreement, and how to collect useful documents. The guide includes instructions on how to communicate with the landlord, notice terms, and references to laws and official forms. If you prefer to avoid disputes, you will discover alternatives like mediation and tips on how to request clarifications before paying an increase.

What does ISTAT adjustment mean?

The ISTAT adjustment links the rent to the consumer price indices indicated in the contract; the measure and frequency must be set in the adjustment clause and are governed by the tenancy laws.[1]

The ISTAT calculation follows the index agreed in the lease.

When can the landlord increase the rent?

The landlord can request an increase if the lease includes an adjustment clause or if there are territorial agreements with certification that provide for it. Increases must respect the agreed percentages and timelines; without a clause or agreement the increase can be challenged.

An increase that lacks the contractual clause or a certified territorial agreement can be challenged.

Practical steps to verify an increase

  • Check the adjustment clause in the lease and keep the signed document.
  • Calculate the expected increase and the monthly amount to pay.
  • Verify the timelines and the days for the landlord's communication.
  • Contact the landlord or mediation services for assistance.
Documenting every communication helps protect your rights.

Frequently Asked Questions

Who should pay the ISTAT adjustment?
Usually the tenant pays the adjustment if provided in the lease; check the clause and contract conditions.[1]
Can the landlord raise the rent without notice?
No, increases follow the agreed schedules or territorial agreements; you can contest illegitimate requests.
How do I register a change in the rent?
If you need to update the lease registration, use the RLI form or the Agenzia delle Entrate instructions.[2]

How-To

  1. Check the lease clause and gather the necessary documents.
  2. Calculate the increase and prepare a table of amounts to be paid.
  3. Send a written communication to the landlord requesting explanations and documentation.
  4. Seek legal assistance or mediation if you cannot reach an agreement.

Key Takeaways

  • Keep copies of documents and communications.
  • Do not pay unjustified increases before receiving written clarifications.
  • Seek support from mediation services or tenant assistance.

Help and Support / Resources


  1. [1] Law 9 December 1998, n. 431 - Normattiva
  2. [2] RLI form and instructions - 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.