Nepean

As of October 8, 2026, Nepean is filled to 72.8% of its total capacity, holding roughly 50 hm³ of water out of a maximum 68 hm³. At this level the reservoir is within its normal operating range.

Over the most recent week on record the fill level has held broadly steady (-1.0 pts), and it is 26.4 points below its level on the same date a year earlier.

Across the readings we hold for Nepean — 1094 data points between October 9, 2023 and October 8, 2026 — the level has ranged from a low of 68.5% (November 18, 2023) to a high of 105.4% (June 7, 2024). On average the reservoir is fullest around June and at its lowest around November.

The dam at Nepean was completed in 1935. It is operated by BOM primarily for water supply. It lies within the Nepean River Basin basin at 34.369°S, 150.582°E.