Frequently asked questions: landslides, floods and earthquakes

Check the address on the flood hazard maps: you can use ISPRA's IdroGEO platform or the report, which tells you in plain words whether the parcel is in a P3, P2 or P1 area and shows the flood zones nearby on a map. For a legally valid check, the binding sources are the river basin authority's plan and the technical office of the Comune (the local council). Ask the seller too whether the building has ever flooded.

It is the third of four classes: strong earthquakes are possible but rare, with an expected ground acceleration between 0.05 and 0.15 g. It does not mean a building is safe or unsafe: what matters is how it was designed and built. The differences between the zones are explained in Seismic zones 1, 2, 3 and 4.

No. Landslide and flood hazard changes from one street to the next: the same municipality can have safe areas and high-hazard areas. That is why the exact position of the building needs checking. The seismic zone, on the other hand, applies to the whole municipality, but even there what matters is the shaking expected at that point and, above all, how the building was built.

Yes, for fires seen by satellite: the report says whether the plot lies inside a burnt area, in which year and, if not, how far away the nearest fire was. It matters because Law 353/2000 is strict: burnt land cannot be built on for ten years, its use cannot change for fifteen, and for fifteen years the deed of sale must mention the restriction or it is void. Satellites see fires of roughly 30 hectares and above (smaller ones only from 2018): the legally binding record is the municipal register of burnt land, and the report explains how to request it.

The seismic zone applies to the whole municipality: it says how much the area can shake, not how the ground under the house responds. Where the municipality has carried out a seismic microzonation study, the report goes down to that spot: how much the ground amplifies shaking compared with bedrock, and whether the study reports landslides, liquefaction or faults. Not every municipality has a study: where it is missing the report says so, because not knowing does not mean the ground is sound.

Yes, across Italy except Sardinia. It says how many contaminated sites there are in the municipality, what state they are in and how many have been cleaned up, and, where the position is reliable, which sites still open are within one kilometre of the address and how far away. It also says whether the home is inside or near a site of national interest (SIN), the large polluted areas such as Porto Marghera or Taranto, where even digging must follow the rules of the clean-up. The sources are the registers of Lombardy and Piedmont, which give the name and street or the cause and substances, and for the other regions MOSAICO, ISPRA's national database. In Lombardy, and in the regions where many sites are given only by municipality, the count stays at municipality level without distances: a site put in the wrong place would be worse than one counted by municipality. In Sardinia the report says we have not looked, because there is no open list there.

The report works it out in euros a year, for a 100 square metre home at the address: it is the average damage, that is the sum of every possible damage weighted by how likely it is. In Milan, away from rivers, it is about twenty euros a year; in an area that floods about every 30 years it ranges from a few hundred to over 1,500 euros. It is the figure to set beside the premium of a natural disaster insurance policy. It uses the European damage models (ESRM20 for earthquakes, JRC for water) with the official Italian hazard from INGV and ISPRA, and building costs updated by Istat. It gives a range, because open data do not say how a single home is built; landslides are not in the figure. The method is on the page What floods and earthquakes cost.