#	County	Water Quality Score	Overall Score
1	Atchison County, MO	86	58.3
2	Barton County, MO	86	44.6
3	Bollinger County, MO	86	54.3
4	Boone County, MO	86	39.5
5	Buchanan County, MO	86	31.1
6	Callaway County, MO	86	39.7
7	Carter County, MO	86	57.5
8	Christian County, MO	86	38.5
9	Clark County, MO	86	55.1
10	Clinton County, MO	86	47.7
11	Cole County, MO	86	54.9
12	Cooper County, MO	86	56.7
13	Crawford County, MO	86	40.7
14	Dallas County, MO	86	59
15	Dent County, MO	86	55.5
16	Douglas County, MO	86	60.8
17	Grundy County, MO	86	51
18	Jackson County, MO	86	35.7
19	Johnson County, MO	86	44.9
20	Knox County, MO	86	66
21	Laclede County, MO	86	43.7
22	Linn County, MO	86	61.9
23	Macon County, MO	86	52.6
24	Madison County, MO	86	46
25	Maries County, MO	86	64
26	Randolph County, MO	86	49.9
27	Schuyler County, MO	86	55.5
28	Shannon County, MO	86	61.3
29	St. Charles County, MO	86	48.2
30	St. Louis city, MO	86	26.2
31	St. Louis County, MO	86	36.6
32	Worth County, MO	86	59.2
33	Wright County, MO	86	64.2
34	Greene County, MO	69.5	54.4
35	Cape Girardeau County, MO	69	42.6
36	Jasper County, MO	65.8	32
37	Livingston County, MO	61.2	52.7
38	Ray County, MO	59.8	42.2
39	Polk County, MO	59.6	44.3
40	Marion County, MO	58.3	42.3
41	Pulaski County, MO	58.3	49.8
42	Platte County, MO	56.3	45.2
43	Barry County, MO	52.1	45.9
44	Jefferson County, MO	50.5	40.4
45	Warren County, MO	50.3	43.2
46	Camden County, MO	49.9	48.5
47	Butler County, MO	49.5	37.9
48	Phelps County, MO	49.5	43
49	Vernon County, MO	48.3	42
50	Newton County, MO	47	42.6
51	Lafayette County, MO	46.9	56.2
52	Moniteau County, MO	46.7	59.1
53	Perry County, MO	46.2	47.2
54	Taney County, MO	46.1	42.2
55	Oregon County, MO	45.8	60
56	Audrain County, MO	45.5	51.2
57	Ripley County, MO	45	49.8
58	Daviess County, MO	44.7	53.6
59	Osage County, MO	44	67.2
60	Howell County, MO	43.8	49.1
61	Adair County, MO	42.8	44.3
62	Saline County, MO	42.4	42.8
63	Montgomery County, MO	42	53.4
64	St. Clair County, MO	41	59.1
65	Dade County, MO	39.7	44.1
66	Webster County, MO	39.2	50
67	Franklin County, MO	38.6	42.5
68	Howard County, MO	38.4	52.4
69	Benton County, MO	38.2	50.4
70	Dunklin County, MO	38.1	40.9
71	Cass County, MO	37.1	33.2
72	Gasconade County, MO	36.9	59.2
73	Lewis County, MO	36.2	62.1
74	Stone County, MO	35.4	52.2
75	Carroll County, MO	34.6	58.1
76	Clay County, MO	34.5	45.5
77	McDonald County, MO	33.8	44.7
78	Washington County, MO	32.6	51.4
79	Putnam County, MO	32.2	62.9
80	Reynolds County, MO	30	66.2
81	Stoddard County, MO	29.3	47
82	Nodaway County, MO	28.4	50.3
83	Andrew County, MO	28.1	53.8
84	Miller County, MO	27.5	54.3
85	Pemiscot County, MO	25.5	34.6
86	Texas County, MO	25.4	50.3
87	Pettis County, MO	24.9	41.1
88	Henry County, MO	24.5	44.5
89	Lawrence County, MO	24.2	45.6
90	Sullivan County, MO	24.1	62.4
91	Scott County, MO	22.9	54
92	Wayne County, MO	22.7	50
93	Harrison County, MO	22.2	50.3
94	New Madrid County, MO	20.3	38.1
95	Ralls County, MO	19.9	61.9
96	Ste. Genevieve County, MO	19.9	54
97	Cedar County, MO	19.2	45.4
98	Chariton County, MO	19.1	61.3
99	Holt County, MO	18.2	57.5
100	Mississippi County, MO	18.1	35.4
101	Hickory County, MO	17.5	57.8
102	St. Francois County, MO	16.7	37.2
103	Pike County, MO	16.1	54.6
104	Shelby County, MO	14.2	60.1
105	Ozark County, MO	11.4	60.2
106	Lincoln County, MO	11.1	45
107	Caldwell County, MO	10.9	64.7
108	DeKalb County, MO	10	55.9
109	Bates County, MO	9.6	45.2
110	Morgan County, MO	9.5	53.7
111	Scotland County, MO	8.4	60.6
112	Gentry County, MO	7.1	57.1
113	Iron County, MO	5.5	59.3
114	Monroe County, MO	4.6	58.6
115	Mercer County, MO	4.3	62.8

Data Source

Water Quality data from WaterByCounty. See full details at WaterByCounty. Data updated February 2026.