Casares de Arbas

As of September 7, 2026, Casares de Arbas is filled to 56.8% of its total capacity, holding roughly 21 hm³ of water out of a maximum 37 hm³. At this level the reservoir is within its normal operating range. Of that total, about 33 hm³ is usable (live) storage.

Over the most recent week on record the fill level has fallen by 2.7 percentage points, and it is 5.4 points above its level on the same date a year earlier.

Across the readings we hold for Casares de Arbas — 419 data points between September 4, 2018 and September 7, 2026 — the level has ranged from a low of 24.3% (October 18, 2022) to a high of 97.3% (March 31, 2020). On average the reservoir is fullest around May and at its lowest around November.

It is operated by CHD primarily for multiple purposes. It lies within the Duero basin at 42.928°N, 5.761°W.