Reservoir · Washington · United States · BOR RISE
Rimrock Lake
Rimrock Lake and Tieton Dam
42.5% full
Capacity
244.23 hm³
Volume stored
104 hm³
Coordinates
46.657°N, 121.129°W
Last updated
2026-09-30
Current fill
42.5%vs 7 days ago
-8.1%losing
vs 1 year ago
+28.5%year-over-year
7-day trend
↓falling
Data source: BOR RISE — US Bureau of Reclamation — 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: 2026-09-30.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 46.657, -121.129 · Open in Google Maps
About Rimrock Lake
As of September 30, 2026, Rimrock Lake is filled to 42.5% of its total capacity, holding roughly 104 hm³ of water out of a maximum 244 hm³. At this level the reservoir is within its normal operating range.
Over the most recent week on record the fill level has fallen by 8.1 percentage points, and it is 28.5 points above its level on the same date a year earlier.
Across the readings we hold for Rimrock Lake — 2181 data points between October 2, 2021 and September 30, 2026 — the level has ranged from a low of 5.8% (October 13, 2024) to a high of 100.0% (June 30, 2022). On average the reservoir is fullest around June and at its lowest around October.
It is operated by BOR primarily for multiple purposes. It lies within the Washington basin at 46.657°N, 121.129°W.
Key facts
- Current fill level
- 42.5%
- Water stored
- 104 hm³
- Total capacity
- 244 hm³
- 7-day change
- ▼ 8.1 pts
- Year-on-year
- ▲ 28.5 pts
- Primary use
- Multipurpose
- River basin
- Washington
- Operator
- BOR
- Coordinates
- 46.657°N, 121.129°W
- Last updated
- September 30, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 30 Sep 2026 | 42.5% | 104 |
| 29 Sep 2026 | 43.5% | 106 |
| 27 Sep 2026 | 45.8% | 112 |
| 26 Sep 2026 | 47.1% | 115 |
| 25 Sep 2026 | 48.2% | 118 |
| 24 Sep 2026 | 49.5% | 121 |
| 23 Sep 2026 | 50.6% | 124 |
| 22 Sep 2026 | 51.8% | 126 |
| 21 Sep 2026 | 52.9% | 129 |
| 20 Sep 2026 | 53.8% | 132 |
| 19 Sep 2026 | 54.9% | 134 |
| 18 Sep 2026 | 55.8% | 136 |