Italy’s water resources are on the wane. To mark World Water Day, celebrated on Sunday 22 March, ISPRA (the Italian Institute for Environmental Protection and Research) has released the findings of the BIGBANG model. This model provides estimates for the components of the national hydrological balance, a quantitative overview of water resources, and the hydrological situation – in this instance, for the year 2025 – by analysing trends and deviations from long-term average values (1951–2025) and the 1991–2020 climatological period.
In summary, the data shows that total precipitation in our country last year amounted to 963.4 mm – approximately 291 billion m³ – representing a decrease of about 9% compared to 2024, a year of abundant rainfall. On a more positive note, 2025 saw a 2% increase relative to the average annual precipitation for the 1991–2020 period, which stands at roughly 285 billion m³. However, regarding the amount of precipitation net of losses from evapotranspiration (referred to in technical terms as the "renewable water resource" and estimated at around 128 billion m³), the figure was more than 7% lower than the long-term annual average (approx. 138 billion m³), 4% lower than the average of the last thirty-year climatological period, and approximately 19% lower than in 2024. This confirms the negative trend observed from 1951 to the present day, particularly regarding the availability of renewable water resources at a national level.
"Faced with the data before us, we can neither delay nor resign ourselves. We must act in a proactive and forward-thinking manner," states ISPRA President Maria Alessandra Gallone. "The issue of water is a national priority that we will help to publicise through our scientific system, to increasingly strengthen the culture of water resource management and to stand alongside institutions and local territories. It is fundamental," Gallone continues, "to inform the public on how to reduce waste and to promote a culture of sustainable water use and the reuse of wastewater."
The monitoring has also yielded other interesting data: the wettest month of 2025 was March, with 114.3 mm. This represents a positive anomaly of +48% compared to the long-term average value for 1951–2025 (77.3 mm). This was followed by November with just over 95 mm; while usually one of the rainiest months, on this occasion it recorded a 20% decrease compared to the long-term average. As for July and August, the customary lack of rainfall was overturned by a surplus of 35% and 42% respectively compared to long-term averages.
Regarding the various areas of the peninsula, those suffering most compared to the last thirty-year climatological period were the Southern Apennines (-10% precipitation and -21% water resources) and the Central Apennines (-7% and -30% respectively). In Sardinia and Sicily, water resources decreased, recording deficits of 12% and 13%. Overall, drought conditions in the centre-south and the islands were less severe than in previous years.
