The “compliance letters” sent by the Revenue Agency have raised considerable concern: when is it truly mandatory to submit a new Docfa after carrying out building works?
With the recent Resolution No. 21/E of June 5, 2026, the Revenue Agency — prompted by our National Council of Surveyors — has provided decisive clarifications that change the operational approach for us professionals.
Here are the key points that every property owner and every professional should know:
✅ Not Only Superbonus The guidelines apply to all building interventions, not only those with tax benefits. The cadastral update obligation applies whenever variations affect category, class, consistency or, more generally, the ordinary income potential of the property.
⚡ The “Systems Case”: The 15% Rule This is the most anticipated update. If the intervention concerns only the expansion of system installations (e.g., installation of photovoltaic systems, storage systems, heat pumps), the cadastral update is necessary only if it results in an increase in the cadastral income value exceeding 15%.
📊 How Is This Increase Assessed? The Agency proposes a simplified calculation criterion:
- Calculate the “pre-intervention” cadastral value (Income x Multiplier D.M. 5646/1991).
- Add the value of the systems calculated using the costs from the 1988-1989 biennium.
- If the difference between “before” and “after” exceeds 15%, the variation must be declared.
🔍 The Central Role of the Surveyor Determining cadastral relevance is not automatic, but requires a precise technical assessment. The professional must verify whether the current classification still corresponds to the actual state and prepare a comprehensive technical report in the Docfa, specifying the characteristics of the new systems (e.g., nominal power of the photovoltaic system).
🏗️ Missing Categories? No Obstacle If the works result in the property falling into a category or class not present in the tariff framework of the census area, we professionals may propose categories present in neighboring areas or nearby municipalities, ensuring continuity of the update.
In summary: not all works require an increase in taxes (income), but all require a preliminary technical analysis to avoid penalties or future assessments.
Do you have questions about the cadastral compliance of your property after a renovation or the installation of a system? Let us discuss it in the comments or contact us for a professional assessment.
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