US States Water Quality Rankings
Explore water quality data for all 50 US states. States are ranked by average water quality score based on EPA SDWIS data for 187 public water systems.
Trending Cities
1
Washington
WA · 480 systems · 9.1M people
95 A
2
North Dakota
ND · 92 systems · 0.7M people
93 A
3
Delaware
DE · 62 systems · 1.0M people
91 A
4
Maryland
MD · 165 systems · 5.4M people
91 A
5
Nebraska
NE · 140 systems · 1.6M people
91 A
6
South Dakota
SD · 115 systems · 0.8M people
91 A
7
California
CA · 1,081 systems · 40.8M people
90 A
8
Michigan
MI · 584 systems · 7.4M people
90 A
9
Minnesota
MN · 362 systems · 4.5M people
90 A
10
South Carolina
SC · 249 systems · 4.6M people
89 B
11
Wyoming
WY · 74 systems · 0.5M people
89 B
12
New Hampshire
NH · 99 systems · 0.8M people
88 B
13
Maine
ME · 93 systems · 0.6M people
87 B
14
Ohio
OH · 602 systems · 10.4M people
87 B
15
Oregon
OR · 233 systems · 3.7M people
87 B
16
Virginia
VA · 343 systems · 7.4M people
87 B
17
Alabama
AL · 441 systems · 6.1M people
86 B
18
Montana
MT · 124 systems · 0.8M people
86 B
19
Indiana
IN · 431 systems · 5.2M people
85 B
20
Wisconsin
WI · 403 systems · 4.1M people
85 B
21
Georgia
GA · 429 systems · 10.3M people
84 B
22
Idaho
ID · 126 systems · 1.5M people
84 B
23
New York
NY · 682 systems · 18.0M people
84 B
24
Tennessee
TN · 389 systems · 7.9M people
84 B
25
Vermont
VT · 85 systems · 0.4M people
84 B
26
Arkansas
AR · 374 systems · 2.9M people
82 B
27
Colorado
CO · 328 systems · 7.0M people
82 B
28
Connecticut
CT · 104 systems · 2.8M people
80 B
29
Kansas
KS · 284 systems · 2.7M people
80 B
30
Missouri
MO · 519 systems · 5.5M people
80 B
31
Nevada
NV · 113 systems · 3.4M people
79 B
32
Hawaii
HI · 66 systems · 1.5M people
78 B
33
Texas
TX · 2,218 systems · 31.9M people
78 B
34
North Carolina
NC · 470 systems · 9.2M people
76 B
35
Mississippi
MS · 629 systems · 3.1M people
74 C
36
Iowa
IA · 335 systems · 2.8M people
73 C
37
Massachusetts
MA · 321 systems · 10.0M people
73 C
38
Pennsylvania
PA · 748 systems · 11.5M people
73 C
39
Illinois
IL · 874 systems · 11.9M people
69 C
40
Rhode Island
RI · 41 systems · 1.1M people
69 C
41
New Jersey
NJ · 367 systems · 8.9M people
68 C
42
Kentucky
KY · 334 systems · 4.6M people
66 C
43
Louisiana
LA · 501 systems · 5.0M people
66 C
44
Florida
FL · 629 systems · 21.8M people
64 C
45
Utah
UT · 219 systems · 3.7M people
64 C
46
New Mexico
NM · 163 systems · 1.9M people
63 C
47
Arizona
AZ · 350 systems · 7.4M people
57 D
48
West Virginia
WV · 248 systems · 1.5M people
53 D
49
Oklahoma
OK · 405 systems · 3.5M people
41 F
50
Alaska
AK · 53 systems · 0.6M people
10 F
State water quality FAQs
Which US states have the best drinking water quality? +
WaterQ ranks states by average system score from EPA SDWIS data. Open a state page to review score breakdowns, violations, and top-performing systems.
How often are state water quality rankings updated? +
State rankings refresh when new EPA SDWIS data is processed. Check each page for the latest update context and compare against other states.
Can I compare cities or systems inside a state? +
Yes. From each state page you can drill into cities and public water systems, then compare quality metrics, grades, and violation histories.
Next steps: explore the national rankings, browse city-level reports, or use search to find a specific water system.