The IMU is a municipal property tax charged to those who hold ownership or equivalent real rights over real estate. This article provides a compact, operational roadmap to recognize the obligated parties, identify common exemptions and assemble the paperwork needed for self-assessment. It integrates normative pointers
and administrative practice sourced from the national guidance such as the Vademecum IMU 2026, and from procedures that local authorities may adopt, without replacing tailored professional advice.
Read on for a stepwise explanation of liability, the most relevant exclusions including the treatment of the first home, the arithmetic that produces the tax base, and the documents and deadlines you should track to avoid penalties. Throughout the
text the most important legal and fiscal terms appear in bold, and defined concepts are emphasized with italics so you can quickly spot what matters when preparing payments or a declaration.
Who is liable and how responsibility is shared
The primary debtor is the property owner, but the obligation passes alternatively to holders of real rights like usufruct, use, right of habitation, surface and enfiteusi. In special situations the
law names other liable subjects: a parent who receives the family home by court order, a concessionaire of state land, the lessee under a finance lease from the stipulation date, the member assigned a cooperative dwelling at possession, an heir from acceptance of succession, and the condominium administrator for autonomously registered common parts. When several persons are responsible for the same asset each calculates their own portion according to their ownership share, months of possession and any individual reliefs.
Special cases and proportional calculation
For co-ownership or mixed rights you must compute the tax for each participant separately: apply the individual’s percentage of ownership, count only the months of possession during the tax year and factor in any reductions that apply to specific quotas. This means that residence status, contractual forms such as comodato (free loan), and rights recorded in the land register directly affect the assessment for each co-owner.
Exemptions, the main residence and assimilations
Some property types are excluded from IMU: agricultural land, instrumentally used rural buildings noted as D/10, public buildings used for institutional purposes, places of worship and properties destined for cultural activities. The main residence is generally exempt (with the exception of luxury categories A/1, A/8 and A/9). One pertinenza in each category C/2, C/6 and C/7 may be considered alongside the main home. Additional assimilations include undivided cooperative housing, social housing used as a primary dwelling, the family house assigned to an entrusted parent, and in specific service conditions, dwellings for permanent law enforcement or armed forces personnel.
Temporary or local reliefs
Municipalities can adopt targeted measures: for instance, ad hoc exemptions or reliefs may be specified for damaged or unsafe properties in a particular area. The 2026 national guidance and local resolutions may list exceptional cases—such as buildings destroyed or declared uninhabitable in limited zones—that temporarily modify obligations. Always check municipal acts for any local dispensations before filing.
How to calculate the tax and what documents you need
Calculation starts from the cadastral income: take the rendita catastale, increase it by 5% and multiply the result by the coefficient for the property category to obtain the base imponibile. Typical multipliers include: 160 for category A (except A/10) and for C/2, C/6, C/7; 140 for B and C/3–C/5; 80 for A/10 and D/5; 65 for D (except D/5); 55 for C/1. For buildable land use the market value in common trade at 1 January of the tax year or the date of adoption of urban instruments. For group D assets owned by businesses without a cadastral income, value is taken from accounting entries and updated per D.M. 14/03/2026.
Required data and proof
When preparing calculations, gather: cadastral identifiers (sheet, parcel, sub), the recorded rendita catastale, ownership percentage, possession months and any relevant registration such as a free loan contract. For buildable plots you should add a valuation report and the certificate of urban destination. Claims for inagibilità or historical interest reductions require technical reports or formal administrative acts; the municipality may verify facts before accepting reductions.
Payments, forms and remedies
Standard deadlines are an advance by 16 June and a balance by 16 December (or a single payment by the advance date). The IMU declaration must be filed on the ministerial form by 30 June of the year following the one in which the change occurred. Use model F24 with the codes 3912, 3913, 3916, 3918, 3925 and 3930 for payments. No payment is due if the total yearly liability does not exceed 12 euros. If you miss or underpay, the ravvedimento operoso mechanism allows voluntary correction with reduced penalties. For refunds, instalments or transfers between taxpayers consult the municipal forms and procedures.