Is the house I'm looking at in a flood zone? How to check in Friuli

Italian flood maps draw three scenarios, set by the EU Floods Directive as adopted in Italy through Legislative Decree 49/2010:

• P3, high hazard: frequent floods, expected on average every 20–50 years.
• P2, medium hazard: infrequent floods, 100–200 years. The IdroGEO platform of ISPRA, the national environmental research institute, uses it for its summaries of people and buildings at risk, and so does this page.
• P1, low hazard: rare or extreme events; it marks the widest area the water can reach.

The three are not added up: they are three hypotheses for the same ground, from the most likely to the widest. A return period is an average, not a timetable, and a rare flood can come back within a few years.

Landslide classes run from P4 (very high) to P1 (moderate), plus areas flagged for attention. We count P3 and P4 together.

Regional totals from ISPRA's IdroGEO platform:

• P2 flood areas: 38,395 buildings and 121,318 residents;
• P3, where floods come often: 18,860 buildings;
• landslide P3+P4: 3,276 buildings (0.6% of the total) and 3,990 residents.

The towns with the highest share of buildings in flood areas are all on the plain or the coast. Landslides are mostly a mountain matter and touch few homes: 125 towns have not a single one.

In some towns on the lower Friulian plain almost everything built is in P2: Muzzana del Turgnano 100.0%, Pocenia 99.7%, Precenicco 99.5%, Palazzolo dello Stella 98.5%. Latisana stands at 76.2%, Codroipo at 69.6%. Not all of the plain is like this: Cervignano stands at 7.1%, San Giorgio di Nogaro at 4.5%.

Cities are not exempt: the P3 areas, which flood most often, hold 1,573 buildings in Pordenone and 1,418 in Udine. On the coast Grado has 53.2% of its buildings in P2, and storm surges or acqua alta may fall outside these scenarios.

The highest shares are in Carnia, the Natisone valleys and Erto e Casso: Treppo Ligosullo 27.2%, Drenchia 21.4%, Enemonzo 19.6%. By share of land, Resiutta comes first, with 18% of its area in P3 or P4.

Water counts up here too. In Bordano 12% of the land is landslide P3+P4 but only 2.5% of the buildings, while 17.2% stand in P2 flood areas.

1. IdroGEO (ISPRA): type in the address and the map shows the flood and landslide hazard areas around the house. The quickest first look.
2. The official flood maps. Friuli lies in the Eastern Alps river basin district, where the reference for flood hazard is the basin authority's Flood Risk Management Plan, updated by the plan approved in December 2022; its maps are on the SIGMA portal. For landslides and avalanches the hydrogeological plan (PAI) still applies, basin by basin.
3. The zoning certificate (certificato di destinazione urbanistica), issued by the town hall, sets out the planning rules for the plot. It must be attached to the deed when land is sold; for a house with grounds under 5,000 m² it is not required, but the town hall issues it on request.
4. Ask the seller how high the ground floor sits above the street, whether water has ever come in, and what work has been done.

An independent surveyor reads the maps; the notary draws up the deed. Earthquakes have their own guide.

• They are shares per town, not per house: the same village can have streets in P2 and streets that stay dry. The map at the exact spot decides.
• Flood figures come from ISPRA's 2020 mosaic and the buildings of the 2011 census, so newer houses are missing, and the plan's current maps may be more recent.
• Landslide figures come from the 2024 mosaic of the hydrogeological plans, with buildings from the 2025 national topographic database: the two counts rest on different bases.