United States39 states · USBR official data

Reservoir Watch

Official storage levels across 551 reservoirs in 39 states. Data from the US Bureau of Reclamation.

Average fill

56.7%

Total volume

203.6 km³

Reservoirs

551

Critical

Low level

Fill by state

Hover for details · USBR coverage

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Status:Critical (<20%)Low (20–40%)Normal / High (>40%)States without color = no USBR reservoirs

US at a glance

National average fill

56.7%

203,616 of 358,868 hm³ stored

Reservoirs

551

States

Total capacity

358.9 km³

Volume stored

203.6 km³

Critical

Low level

Coverage: USBR (Bureau of Reclamation) reservoirs — primarily 17 western states. Eastern US reservoirs managed by USACE are not yet included. Last reading: 2026-09-17.

National fill — multi-year

By state

Sorted by capacity

Utah

27 reservoirs

Low

Average fill

28.9%

11,228 hm³ storedView →

Nevada

7 reservoirs

Low

Average fill

27.2%

10,089 hm³ storedView →

Montana

24 reservoirs

Average fill

80.6%

27,841 hm³ storedView →

California

33 reservoirs

Average fill

61.5%

20,821 hm³ storedView →

South Dakota

14 reservoirs

Average fill

77.7%

25,098 hm³ storedView →

North Dakota

11 reservoirs

Average fill

75.4%

18,109 hm³ storedView →

Oklahoma

47 reservoirs

Average fill

70.8%

12,899 hm³ storedView →

Texas

28 reservoirs

Average fill

64.7%

11,283 hm³ storedView →

Kentucky

17 reservoirs

Average fill

58.3%

9,259 hm³ storedView →

Missouri

10 reservoirs

Low

Average fill

31.4%

3,539 hm³ storedView →

Wyoming

25 reservoirs

Low

Average fill

37.0%

3,686 hm³ storedView →

Kansas

34 reservoirs

Average fill

58.2%

4,997 hm³ storedView →

Louisiana

3 reservoirs

Average fill

68.3%

4,952 hm³ storedView →

Idaho

20 reservoirs

Low

Average fill

24.4%

1,742 hm³ storedView →

Arizona

10 reservoirs

Average fill

60.3%

4,017 hm³ storedView →

New Mexico

16 reservoirs

Low

Average fill

21.4%

1,344 hm³ storedView →

Minnesota

9 reservoirs

Average fill

62.4%

3,349 hm³ storedView →

Tennessee

6 reservoirs

Average fill

87.0%

4,147 hm³ storedView →

Colorado

34 reservoirs

Average fill

45.5%

2,092 hm³ storedView →

Georgia

6 reservoirs

Average fill

78.7%

3,225 hm³ storedView →

Arkansas

2 reservoirs

Average fill

88.2%

3,053 hm³ storedView →

Mississippi

12 reservoirs

Average fill

58.1%

1,885 hm³ storedView →

Oregon

24 reservoirs

Critical

Average fill

15.4%

465 hm³ storedView →

Washington

16 reservoirs

Low

Average fill

32.3%

929 hm³ storedView →

Virginia

5 reservoirs

Average fill

73.1%

1,666 hm³ storedView →

New York

8 reservoirs

Average fill

83.9%

1,835 hm³ storedView →

Alabama

7 reservoirs

Average fill

95.4%

1,866 hm³ storedView →

Ohio

27 reservoirs

Average fill

53.8%

989 hm³ storedView →

Massachusetts

2 reservoirs

Average fill

80.9%

1,461 hm³ storedView →

Nebraska

27 reservoirs

Average fill

46.7%

739 hm³ storedView →

Pennsylvania

13 reservoirs

Average fill

79.0%

1,215 hm³ storedView →

Indiana

5 reservoirs

Average fill

72.4%

823 hm³ storedView →

Illinois

5 reservoirs

Average fill

81.7%

783 hm³ storedView →

Iowa

4 reservoirs

Average fill

84.0%

731 hm³ storedView →

West Virginia

9 reservoirs

Average fill

78.1%

610 hm³ storedView →

North Carolina

3 reservoirs

Average fill

68.5%

393 hm³ storedView →

Florida

1 reservoir

Average fill

90.4%

453 hm³ storedView →

South Carolina

0 reservoirs

Critical

Average fill

0.0%

0 hm³ storedView →

Wisconsin

0 reservoirs

Critical

Average fill

0.0%

0 hm³ storedView →

All reservoirs

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US territory · tracked separately

Puerto Rico — 19 reservoirs

Puerto Rico publishes reservoir elevation, not storage, so its reservoirs cannot be given a fill % or ranked on the map above. They have their own page, in metres above sea level, with records back to 1990.

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States shown as N/A

Alaska, Connecticut, Delaware, District of Columbia, Hawaii, Maine, Maryland, Michigan, New Hampshire, New Jersey, Rhode Island and Vermont have no reservoirs in the federal datasets we use — USGS NWIS, the Bureau of Reclamation (RISE) and USACE — which cover primarily the 17 western Reclamation states. Eastern, coastal and non-contiguous states are mostly managed by state agencies or USACE districts without a public storage API, so they appear as N/A on the map. We're adding sources as they become available.

Dataset coverage

58%of national storage capacity has public data

Tracked

572

reservoirs

With data

572

reservoirs

Tracked capacity

371,177

hm³

Source: USGS NWIS · USACE CWMS · Bureau of Reclamation RISE · CDEC (California) · SRP (Arizona)

Federal systems track a subset of US reservoirs. Many state-managed and smaller reservoirs have no public machine-readable storage data. The US has thousands of reservoirs beyond those covered here.

About reservoirs in United States

As of September 17, 2026, the reservoirs we track across United States that report live levels hold roughly 203,616 hm³ of water — about 56.7% of their combined capacity. Taken together, United States's reservoirs are within their normal operating range.

Across the region, 95 reservoirs are at critically low levels and 90 are low. Bankhead Lock and Dam is the fullest at 105.0%, while Mud Mountain Lake is the lowest at 0.0%.

Over the most recent week on record, 54 reservoirs rose and 89 reservoirs fell across United States.

Storage figures for United States come from USGS · USACE · BOR · CDEC · SRP; the most recent reading is from September 17, 2026. Each reservoir below links to its own page with full history and seasonal context.

United States at a glance

Reservoirs tracked: 572
Average fill: 56.7%
Water stored: 203,616 hm³
Combined capacity: 371,177 hm³
At critically low levels: 95
Fullest: Bankhead Lock and Dam (105.0%)
Lowest: Mud Mountain Lake (0.0%)
Last updated: September 17, 2026