The thirteen reservoirs that Canal de Isabel II uses to supply the Madrid region start the new hydrological year with 590 cubic hectometres in storage, 62.5% of their maximum capacity. That is 0.7 percentage points below the average for this time of year, and the public water company describes it as normal, with supply guaranteed for the coming months.
The 2025/2026 hydrological year, from October to September, brought 589.8 litres of rain per square metre, 4.7% below historical records. Even so, rivers delivered more water to the reservoirs than the average of the last 30 years, and a single month explains it: of the 739.4 hm³ that flowed in over the year, 369.6 hm³ arrived in February, almost half, with exceptional rainfall. In the other eleven months inflows were below the usual level for each period.
September ended dry and warm, with only 2.6 l/m² and 6.9 hm³ of inflows, below the average for the month. Canal de Isabel II also notes that over the last five hydrological years the rain gauges in the city of Madrid have recorded more rainfall than those at the dams.
On the demand side, September consumption was 12.6% higher than in September 2025. Over the whole year 529.1 hm³ was abstracted for supply: the first time since 2011/2012 that it has exceeded 500 hm³. Canal de Isabel II’s statement adds that the region has gained around half a million inhabitants since then.
The company calls for responsible water use and points out that savings do not depend on users alone. In recent years it has stepped up water reuse, pipe renewal and active leak detection, and with these measures and public awareness, per capita consumption in the Madrid region has fallen by more than 30% since the 2005 drought, according to the company.
Reservoir regulation and water supply are part of hydraulic engineering, one of North Line’s areas of work.
Sources: Canal de Isabel II, “Empieza el nuevo año hidrológico con los embalses de Canal de Isabel II al 62,5 % de su capacidad máxima” (The new hydrological year begins with Canal de Isabel II reservoirs at 62.5% of maximum capacity), 1 October 2026, and IndustriAmbiente, 2 October 2026. Image: Santillana reservoir, Manzanares el Real (Madrid). Deensel, CC BY 2.0, via Wikimedia Commons (cropped).
