State · United States · USGS · BOR · USACE · CDEC
Illinois
82.5% average fill
Measured
5
Volume stored
746 hm³
Measured capacity
905 hm³
Below month average
1 of 3
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Drought Monitor · 27 October 2026
Weekly map · area in each categoryDrought status
29.3%
of the area in drought (D1 or worse)
Worst category: D2 severe drought
up 5.4 points on the week
Severe or worse (D2+)
4.0%
Extreme or worse (D3+)
0.0%
DSCI
900–500
People in drought
950,000
Reservoirs (reservoirs.earth)
82.5% full5 tracked
Reservoirs on drought ground
5 of 53 in D2 or worse
As of the 27 October 2026 U.S. Drought Monitor map, 29.3% of Illinois was in drought (D1 or worse). The 5 reservoirs we track in Illinois were 82.5% full on their latest readings. 5 of 5 tracked reservoir sites sit inside the drought area, 3 of them in severe drought (D2) or worse.
The Drought Monitor maps where conditions are dry this week — rainfall, soil moisture, streamflow — not how much water is stored. Reservoir storage lags it by months, so a region can be in drought with full reservoirs, or out of drought with empty ones. Source: droughtmonitor.unl.edu. The U.S. Drought Monitor is jointly produced by the National Drought Mitigation Center at the University of Nebraska-Lincoln, the United States Department of Agriculture, the National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration. Map courtesy of NDMC.
Reservoirs
Sorted by capacityShelbyville Pool
Updated 2026-10-30· 97% of month avg· D1
Carlyle Pool
Updated 2026-10-30· D1
Rend Pool
Updated 2026-10-30· D2
Sub
Updated 2026-10-30· 122% of month avg· D2
Sub Casey
Updated 2026-10-30· 137% of month avg· D2
Storage from official US gauges (USGS, USACE, Bureau of Reclamation, CDEC) and, in Texas, the Texas Water Development Board. Fill % uses design capacity from the National Inventory of Dams where available; Water Data for Texas lakes use that board's conservation capacity; a few sites without a match fall back to the 5-year maximum. "% of month avg" compares the current fill with the reservoir’s own average for this calendar month over its readings on record. D0–D4 is the U.S. Drought Monitor category of the ground at the reservoir’s coordinates on the latest weekly map — local conditions, not storage.
About reservoirs in Illinois
As of October 30, 2026, the reservoirs we track across Illinois that report live levels hold roughly 746 hm³ of water — about 82.5% of their combined capacity. Taken together, Illinois's reservoirs are high.
None of the tracked reservoirs are currently at critically low levels. Carlyle Pool is the fullest at 103.4%, while Sub is the lowest at 55.4%.
Over the most recent week on record, 2 reservoirs rose and 1 reservoir fell across Illinois.
Storage figures for Illinois come from USGS · USACE · BOR · CDEC; the most recent reading is from October 30, 2026. Each reservoir below links to its own page with full history and seasonal context.
Illinois at a glance
- Reservoirs tracked
- 5
- Average fill
- 82.5%
- Water stored
- 746 hm³
- Combined capacity
- 905 hm³
- Fullest
- Carlyle Pool (103.4%)
- Lowest
- Sub (55.4%)
- Last updated
- October 30, 2026