Which seismic zone is the house in, and what changes?
Each municipality is classified by its region in one of four seismic zones, from 1 (the most hazardous) to 4 (the least hazardous). The zone does not stop you buying or renovating, but it decides how structural works are designed.
The four zones
| Zone | Civil Protection description | Reference acceleration |
|---|---|---|
| 1 | the most hazardous: the probability of a strong earthquake is high | 0,35 g |
| 2 | strong earthquakes are possible | 0,25 g |
| 3 | strong earthquakes less likely than in zones 1 and 2 | 0,15 g |
| 4 | the least hazardous: the probability of an earthquake is very low | 0,05 g |
In the Civil Protection list updated in May 2025, 796 municipalities are in zone 1, sub-zones included (processing: SRI Group BV (VAT BE1037052239)).
Other data often matter for the same property too, such as the location data and landslide and flood risk. You can see how a dossier brings them together in the sample dossier.
Sub-zones
Some regions used only three zones or introduced sub-zones (such as 2A, 2B or 3S): the region’s rule defines their meaning. A large municipality can have several sub-zones, like Rome.
What changes for a buyer
- Structural works follow the technical building standards and, where the region requires it, a seismic authorisation or filing.
- The zone alone does not determine the procedure: for structurally relevant works the type of works, the site’s reference acceleration and the regional rules also count (arts. 93 and 94-bis D.P.R. 380/2001). No zone brings a general exemption.
- It is worth asking when and how the building was built and whether there were seismic improvement works.
What Dossier Immobile does
It shows the municipality’s zone with the region’s sub-zones and the date of the list; the municipality pages show it for each municipality.
Does the seismic zone forbid building?
No: it decides how you design, not whether you can build.
Sources
Dossier Immobile is a private service by SRI Group BV (VAT BE1037052239), not connected to any public authority: it brings together public data, with the source and date of every item.
Updated on