Guide to the Declaration of Conformity (DiCo) for plumbing and HVAC installers

What the Declaration of Conformity (DiCo) is

The Declaration of Conformity (DiCo) is the document, introduced by Italian Ministerial Decree 37/2008, with which the installation company certifies that a system was built to industry standards, in compliance with current technical safety norms (UNI, CEI standards) and any filed design projects.

For a plumbing or HVAC company it's the single most important compliance document: without a DiCo the system cannot be put into service, and the client can't obtain occupancy permits, tax incentives (Ecobonus, Conto Termico, Superbonus) or utility contracts.

When the DiCo is mandatory

DM 37/2008 requires a DiCo for systems installed in buildings (residential, commercial, production facilities). The categories relevant to plumbing and HVAC businesses are:

• Heating, air conditioning and refrigeration systems
• Water and sanitary systems
• Combustible gas distribution and utilization systems
• Fire protection systems (extinguishers, detection, smoke evacuation)
• Electrical systems serving heating systems

The DiCo is mandatory for new installations, modifications, extensions and extraordinary maintenance. It isn't required for routine maintenance alone, but the system's service log must still be updated.

The DiCo template: what it must contain

The DiCo template attached to DM 37/2008 (Annex I) is structured into mandatory sections. An incomplete or carelessly filled-out DiCo is the leading cause of disputes during inspections and building permit filings.

Mandatory attachments to the DiCo

The attachments are an integral part of the DiCo. A declaration without the correct attachments is considered incomplete and can be rejected by the municipality, local health authority or issuing body.

• Materials specification report for the components used
• As-built system diagram (floor plan, functional schematic)
• Design project references and the qualified designer's details, if applicable
• Copy of the recognition certificate of technical-professional requirements
• Up-to-date chamber of commerce registration for the company
• Component certifications (boiler, valves, pumps, safety systems)

DiCo and digital traceability: the current framework

Recent regulation hasn't replaced DM 37/2008, but it has strengthened its link with the digital traceability of jobs:

• F-Gas database: for air conditioning systems, the DiCo is tied to the data reported within 30 days of the job.
• EU F-Gas Regulation 2024/573: introduces new certification and refrigerant management requirements that the DiCo must reflect.
• Electronic submission: more and more municipalities and building offices require the digital submission of the DiCo (signed PDF, virtual stamp duty) linked to the building permit file.
• System service log: the DiCo is the reference used for the first entry in the system service log required by DPR 74/2013.

Penalties under DM 37/2008

Article 15 of DM 37/2008 sets out the administrative penalties for the installation company and technical manager in case of violations:

• From €100 to €1,000 for formal or documentary violations (e.g. incomplete DiCo, missing attachments, delayed delivery to the client).
• From €1,000 to €10,000 for more serious violations, such as a missing DiCo on systems subject to a design project or work not built to industry standards with an impact on safety.
• Temporary suspension from the artisan business register or company register in cases of repeated violations.

Regulatory reference: Ministerial Decree of 22 January 2008, no. 37, Art. 15 (Penalties).

How much it costs to prepare a DiCo

The DiCo has no ministerial issuance cost. The real cost for a company is the back-office time needed to gather attachments, transcribe component data-plate details, verify the applicable technical norms and prepare the document ready for signature. On average that's 30-60 minutes per system, plus the time for any follow-up requests from the building office or the client.

On top of that come indirect costs: stamp duty (where required by the receiving body), compliant digital archiving for at least 10 years, and updating templates whenever regulatory references change (e.g. the entry into force of EU Regulation 2024/573). As a market reference, having a DiCo/DiRi drafted by a qualified professional is typically quoted between €200 and €400for a standard residential system (source: indicative Cronoshare 2025 pricing), depending on complexity and the attachments required.

Most common mistakes when filling it out

• Incomplete component data-plate details, or transcribed by hand on site
• Missing technical attachments (materials report, system diagram)
• Technical norms cited generically, without reference to the version in force
• Mismatch between the DiCo and the system service log / F-Gas database
• Technical manager's signature without the qualification matching the DM 37/2008 categories
• Delayed delivery to the client (the DiCo must be issued at the end of the job)

How to automate the DiCo with Clemp

The real cost of the DiCo isn't the signature: it's re-typing data from the job site to the office. Brands and models read off data plates, norms applied, attachments gathered one by one. That's 30-60 minutes of back-office work per system.

Clemp starts from a voice note and photos the technician sends over WhatsApp, and automatically produces:

• A draft DiCo filled out on the DM 37/2008 template
• Automatic extraction of brand, model and serial number from photographed data plates
• A link to the system's record and maintenance service log
• A checklist of missing mandatory attachments before signing

Technical responsibility remains with the qualified professional: Clemp speeds up the preparation, it doesn't replace the signature.

Frequently asked questions about the DiCo