Reservoir · Oklahoma · United States · USGS NWIS
Lake Hefner
83.7% full
Capacity
91.77 hm³
Volume stored
77 hm³
Coordinates
35.583°N, 97.596°W
Last updated
2026-08-13
Current fill
83.7%vs 7 days ago
-2.2%losing
vs 1 year ago
-15.8%year-over-year
7-day trend
↓falling
Data source: USGS National Water Information System (NWIS) — daily reservoir storage volume. Capacity is the design (normal full-pool) capacity from the US National Inventory of Dams (NID); fill % = current volume ÷ design capacity. Last reading: 2026-08-13.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 35.583, -97.596 · Open in Google Maps
About Lake Hefner
As of August 13, 2026, Lake Hefner is filled to 83.7% of its total capacity, holding roughly 77 hm³ of water out of a maximum 92 hm³. At this level the reservoir is high.
Over the most recent week on record the fill level has fallen by 2.2 percentage points, and it is 15.8 points below its level on the same date a year earlier.
Across the readings we hold for Lake Hefner — 1461 data points between August 14, 2022 and August 13, 2026 — the level has ranged from a low of 77.2% (October 22, 2022) to a high of 105.0% (July 12, 2023). On average the reservoir is fullest around February and at its lowest around October.
It is operated by USGS primarily for multiple purposes. It lies within the Oklahoma basin at 35.583°N, 97.596°W.
Key facts
- Current fill level
- 83.7%
- Water stored
- 77 hm³
- Total capacity
- 92 hm³
- 7-day change
- ▼ 2.2 pts
- Year-on-year
- ▼ 15.8 pts
- Primary use
- Multipurpose
- River basin
- Oklahoma
- Operator
- USGS
- Coordinates
- 35.583°N, 97.596°W
- Last updated
- August 13, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 13 Aug 2026 | 83.7% | 77 |
| 12 Aug 2026 | 84.1% | 77 |
| 11 Aug 2026 | 84.4% | 77 |
| 10 Aug 2026 | 84.7% | 78 |
| 9 Aug 2026 | 85.0% | 78 |
| 8 Aug 2026 | 85.3% | 78 |
| 7 Aug 2026 | 85.6% | 79 |
| 6 Aug 2026 | 85.9% | 79 |
| 5 Aug 2026 | 86.3% | 79 |
| 4 Aug 2026 | 86.6% | 79 |
| 3 Aug 2026 | 86.9% | 80 |
| 2 Aug 2026 | 87.2% | 80 |
Frequently asked questions
What is the current water level of Lake Hefner?
As of August 13, 2026, Lake Hefner is at 83.7% of its capacity, holding approximately 77 hm³ of water, according to USGS NWIS data.
Is Lake Hefner reservoir full?
No. As of August 13, 2026, Lake Hefner is high at 83.7% of its capacity, so it is not full.
Is the water level at Lake Hefner rising or falling?
The level at Lake Hefner is falling — it dropped 2.2 percentage points over the latest week on record.
How much water can Lake Hefner hold?
Lake Hefner has a total capacity of 92 hm³.
Where is Lake Hefner reservoir located?
Lake Hefner is located in Oklahoma, United States, within the Oklahoma basin (coordinates 35.583°N, 97.596°W).
What is Lake Hefner used for?
Lake Hefner is used primarily for multiple purposes, and is managed by USGS.