Water Supply Dams in the United States

5,161Total

2135High Hazard

848Significant

Water supply dams create reservoirs that store water for municipal, industrial, and agricultural use. Many of America's cities depend on dam-created reservoirs for their drinking water, making these some of the most critical infrastructure in the country.

Water supply dams are often owned by local governments or public utilities and tend to be well-maintained given their direct impact on public health and municipal operations.

Water Supply Dams by State

State	Count	High Hazard	Tallest (ft)
Texas	993	137	180
California	747	413	422
Colorado	263	127	310
New York	234	111	213
Massachusetts	231	116	245
Pennsylvania	209	175	151
Ohio	204	114	300
Connecticut	179	91	137
Oklahoma	174	71	112
North Carolina	127	91	182
Virginia	124	67	241
Arkansas	122	30	212
Kentucky	103	55	700
Georgia	102	41	180
Missouri	99	49	102
New Jersey	96	60	178
Louisiana	87	7	65
Illinois	80	10	175
Kansas	69	21	80
Oregon	67	29	200
Wyoming	60	16	150
Indiana	56	29	82
Iowa	49	2	79
South Dakota	49	5	55
Alaska	48	11	350
Washington	47	33	200
Maryland	42	27	175
Utah	42	24	391
Alabama	39	5	100
Montana	39	10	101
North Dakota	39	2	72
New Hampshire	38	23	95
Rhode Island	30	16	189
Maine	29	4	70
West Virginia	29	14	123
Vermont	26	7	50
South Carolina	25	12	175
New Mexico	22	18	133
Florida	19	5	90
Tennessee	19	8	95
Michigan	17	4	100
Arizona	16	12	309
Minnesota	16	1	40
Nevada	14	6	123
Mississippi	10	5	65
Hawaii	9	7	54
Delaware	6	5	127
Wisconsin	6	3	37
Puerto Rico	5	5	131
Nebraska	3	0	40
Guam	1	1	135
Idaho	1	0	77

Largest Water Supply Dams

#	Dam	State	Height (ft)	Hazard	Year
1	Abner Fork Dam	Kentucky	700	High
2	Half Mile Dam	Kentucky	545	High
3	Adams Fork Slurry Dam	Kentucky	480	High
4	Pyramid	California	422	High	1974
5	Jordanelle Dam	Utah	391	High	1993
6	Right Fork Dam	Kentucky	370	High
7	Lovely Branch Slurry Dam	Kentucky	360	High
8	Arjay Slurry Impoundment	Kentucky	355	High
9	Pardee	California	352	High	1929
10	Fort Knox Tailings Dam	Alaska	350	Significant	1996
11	Beartree Branch Slurry Impoundment	Kentucky	345	High
12	Bennetts Branch Slurry Dam	Kentucky	340	High
13	Castaic	California	340	High	1973
14	Brushy Fork Slurry Dam	Kentucky	332	High
15	Little Camp Slurry Impoundment	Kentucky	320	High
16	O`shaughnessy	California	312	High	1923
17	Dillon	Colorado	310	High	1963
18	Dillon	Colorado	310	High	1963
19	Olivenhain	California	309	High	2003
20	Bartlett Dam	Arizona	309	High	1939
21	Buckeye Creek Dam	Kentucky	300	High
22	No. 2 Slurry Pond	Ohio	300	High
23	Strontia Springs	Colorado	299	High	1982
24	Left Fork Dam	Kentucky	295	High
25	Diamond Valley Lake	California	284	High	2000
26	Slurry Impoundment 401	Kentucky	280	High
27	Ridges Basin Dam	Colorado	273	High	2008
28	Homestake Project	Colorado	265	High	1967
29	Mathews	California	264	High	1938
30	Stoney Fork Slurry Dam	Kentucky	264	High
31	Britton Branch Refuse Dam	Kentucky	250	High
32	Cedar Springs	California	249	High	1971
33	Cobble Mountain Reservoir Dam	Massachusetts	245	High	1930
34	Clifford D. Craig Memorial Dam	Virginia	241	High
35	Anderson	California	240	High	1950
36	El Capitan	California	237	High	1934
37	Los Vaqueros	California	231	High	1997
38	Peters	California	230	High	1954
39	Pacificorp - Electric Lake	Utah	229	High	1974
40	Ramona	California	228	High	1988
41	Rollins	California	228	High	1965
42	New Lake Arrowhead	California	225	High	1976
43	Little Dell	Utah	224	High	1993
44	San Joaquin Reservoir	California	224	High	1966
45	Cheesman	Colorado	221	High	1905
46	Button Rock	Colorado	214	High	1969
47	Ashokan Dam	New York	213	High	1916
48	Santa Felicia	California	213	High	1955
49	Lake Fort Smith Dam	Arkansas	212	High	1936
50	New Calaveras	California	210	High	2018