Reservoir · New South Wales · Australia · BOM Water Data Online
Nepean
77.5% full
Capacity
68.1 hm³
Volume stored
53 hm³
River
Nepean River
Year completed
1935
Coordinates
34.369°S, 150.582°E
Last updated
2026-09-09
Current fill
77.5%vs 7 days ago
-1.5%losing
vs 1 year ago
-20.3%year-over-year
7-day trend
→stable
Data source: Bureau of Meteorology — Water Data Online (KiWIS) — daily mean storage volume, quality-controlled. Capacity from the BOM Water Storages ArcGIS layer (total design capacity in ML). Last reading: 2026-09-09.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. -34.369, 150.582 · Open in Google Maps
About Nepean
As of September 9, 2026, Nepean is filled to 77.5% of its total capacity, holding roughly 53 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 (-1.5 pts), and it is 20.3 points below its level on the same date a year earlier.
Across the readings we hold for Nepean — 1093 data points between September 11, 2023 and September 9, 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.
Key facts
- Current fill level
- 77.5%
- Water stored
- 53 hm³
- Total capacity
- 68 hm³
- 7-day change
- ▼ 1.5 pts
- Year-on-year
- ▼ 20.3 pts
- Primary use
- Water supply
- River
- Nepean River
- River basin
- Nepean River Basin
- Year completed
- 1935
- Operator
- BOM
- Coordinates
- 34.369°S, 150.582°E
- Last updated
- September 9, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 9 Sep 2026 | 77.5% | 53 |
| 8 Sep 2026 | 77.7% | 53 |
| 7 Sep 2026 | 77.8% | 53 |
| 6 Sep 2026 | 78.0% | 53 |
| 5 Sep 2026 | 78.2% | 53 |
| 4 Sep 2026 | 78.4% | 53 |
| 3 Sep 2026 | 78.7% | 54 |
| 2 Sep 2026 | 79.0% | 54 |
| 1 Sep 2026 | 79.1% | 54 |
| 31 Aug 2026 | 79.2% | 54 |
| 30 Aug 2026 | 79.4% | 54 |
| 29 Aug 2026 | 79.5% | 54 |