Lake Como closes the hydrological year at 36.5 percent of capacity
The ANBI Observatory on ARPA Lombardia data: Lombardy's water reserves close the year with a deficit above 24 percent. October brings rain, but for the lake region the models offer no certainty.
Translated from the Italian original. Leggi in italiano
The 2025-2026 hydrological year closes in the red for northern Italy, and Lake Como is no exception. According to the latest ANBI Water Resources Observatory, reported at the start of October, Lombardy closes with an annual deficit above 24 percent, nearly 350 million cubic meters less in water reserves, based on ARPA Lombardia data. Among the great lakes, Lake Como stands at 36.5 percent of capacity: better than Lake Maggiore (21.3 percent), worse than Lake Garda (45 percent) and Lake Iseo (67.1 percent).
The picture did not emerge overnight. ARPA Lombardia's water reserves bulletin for the situation on July 26, 2026 (issued July 30) already recorded a weekly drop of 36 percent in Lake Como's stored volume, with the Adda-Mera-Lario artificial reservoirs down 12.5 percent. Still-high temperatures, suffering watercourses and scarce snow reserves accompanied the entire season: the deficit, in other words, built up month by month.
October, the month of rains: will it be enough?
Seasonal forecasts for October point to abundant rainfall on the Po valley, particularly in Lombardy, Veneto and Friuli Venezia Giulia. But precisely over the Lombard lake region, Lake Maggiore and Lake Como, the European mathematical model (ECMWF) predicts below-average precipitation. The same report warns the figure is entirely to be verified: those are, normally, the areas that record the heaviest rains, even when less is forecast. In short: October should bring water, but for Lake Como there is no reliable recovery forecast yet.
ANBI draws attention to a dual theme that concerns our lake too: on one side water scarcity, on the other increasingly irregular rainfall, capable of dumping large amounts of water in very short times over restricted areas. It is the combination that makes reserve management ever more delicate: reservoirs are needed to hold water when it comes, and careful management when it does not.
For Lake Como readers, the practical message is twofold. No alert at the moment: levels reflect a difficult year, not an emergency. But the hydrological year that has closed leaves a heavy legacy, and autumn will be decisive in showing whether reserves recover. We will continue following ARPA Lombardia bulletins and ANBI Observatory data in the coming weeks.
