Reservoir · Ohio · United States · USACE CWMS
Tappan Lake
98.9% full
Capacity
43.3 hm³
Volume stored
43 hm³
Coordinates
40.356°N, 81.226°W
Last updated
2026-07-30
Current fill
98.9%vs 7 days ago
0.0%stable
vs 1 year ago
-1.8%year-over-year
7-day trend
→stable
Data source: USACE CWMS — US Army Corps of Engineers — 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: 2026-07-30.
Catchment Weather
Past 30 days + 14-day forecast · Open-Meteo
Satellite imagery: Esri, Maxar, Earthstar Geographics. Map: Esri, HERE, Garmin, © OpenStreetMap contributors. 40.356, -81.226 · Open in Google Maps
About Tappan Lake
As of July 30, 2026, Tappan Lake is filled to 98.9% of its total capacity, holding roughly 43 hm³ of water out of a maximum 43 hm³. At this level the reservoir is high.
Over the most recent week on record the fill level has held broadly steady (+0.0 pts), and it is 1.8 points below its level on the same date a year earlier.
Across the readings we hold for Tappan Lake — 100 data points between July 31, 2021 and July 30, 2026 — the level has ranged from a low of 97.3% (August 9, 2021) to a high of 105.0% (August 18, 2021).
It is operated by USACE primarily for multiple purposes. It lies within the Ohio basin at 40.356°N, 81.226°W.
Key facts
- Current fill level
- 98.9%
- Water stored
- 43 hm³
- Total capacity
- 43 hm³
- 7-day change
- No change
- Year-on-year
- ▼ 1.8 pts
- Primary use
- Multipurpose
- River basin
- Ohio
- Operator
- USACE
- Coordinates
- 40.356°N, 81.226°W
- Last updated
- July 30, 2026
Recent readings
| Date | Fill level | Volume (hm³) |
|---|---|---|
| 30 Jul 2026 | 98.9% | 43 |
| 29 Jul 2026 | 98.9% | 43 |
| 28 Jul 2026 | 99.0% | 43 |
| 27 Jul 2026 | 99.0% | 43 |
| 26 Jul 2026 | 99.0% | 43 |
| 25 Jul 2026 | 99.2% | 43 |
| 24 Jul 2026 | 99.2% | 43 |
| 23 Jul 2026 | 99.4% | 43 |
| 22 Jul 2026 | 99.6% | 43 |
| 21 Jul 2026 | 99.6% | 43 |
| 20 Jul 2026 | 99.4% | 43 |
| 19 Jul 2026 | 99.6% | 43 |
Frequently asked questions
What is the current water level of Tappan Lake?
As of July 30, 2026, Tappan Lake is at 98.9% of its capacity, holding approximately 43 hm³ of water, according to USACE CWMS (US Army Corps of Engineers) data.
Is Tappan Lake reservoir full?
Tappan Lake is essentially full, sitting at 98.9% of capacity as of July 30, 2026.
Is the water level at Tappan Lake rising or falling?
The level at Tappan Lake has been broadly stable over the latest week on record (0.0 points).
How much water can Tappan Lake hold?
Tappan Lake has a total capacity of 43 hm³.
Where is Tappan Lake reservoir located?
Tappan Lake is located in Ohio, United States, within the Ohio basin (coordinates 40.356°N, 81.226°W).
What is Tappan Lake used for?
Tappan Lake is used primarily for multiple purposes, and is managed by USACE.