Horseshoe Reservoir

As of September 30, 2026, Horseshoe Reservoir is filled to 16.9% of its total capacity, holding roughly 27 hm³ of water out of a maximum 162 hm³. At this level the reservoir is critically low.

Over the most recent week on record the fill level has held broadly steady (-0.2 pts), and it is 30.1 points below its level on the same date a year earlier.

Across the readings we hold for Horseshoe Reservoir — 1461 data points between October 1, 2022 and September 30, 2026 — the level has ranged from a low of 5.1% (October 1, 2022) to a high of 82.8% (May 21, 2023). On average the reservoir is fullest around May and at its lowest around November.

It is operated by USGS primarily for multiple purposes. It lies within the Arizona basin at 33.985°N, 111.710°W.