Chromium-6 Contamination

Chromium-6 in Ohio Drinking Water

Ranked by max chromium-6 detected (µg/L) · UCMR 3 data (2013–2015) · Data from EPA SDWIS & UCMR

132

Cities Tested

132

Detected

100%

% Detected

0.33 µg/L

State Avg

▼ 0% vs national

vs National

398

Health Violations

Analysis

Chromium-6 in Ohio: what the data shows

Ohio has 132 cities with chromium-6 data from the EPA's UCMR 3 program (2013–2015). Hexavalent chromium (Cr VI) was detected in 132 of those cities. There is currently no federal MCL for chromium-6 — California's 10 µg/L limit is used as a reference. The state average max detected level is 0.33 µg/L. Chromium-6 occurs naturally in some groundwater aquifers but also from industrial discharge, particularly from steel processing, chrome plating, and leather tanning. It is distinct from trivalent chromium (Cr III), which is an essential nutrient at low doses. The National Toxicology Program and IARC classify chromium-6 as a carcinogen via inhalation; the evidence for drinking water carcinogenicity is strong but regulatory action at the federal level remains pending as of 2026. Reverse osmosis systems effectively remove chromium-6 to near-undetectable levels.

Comparison

Cities exceeding No federal MCL (CA: 10 µg/L)

Ohio

100%

132 of 132 cities

← = Exactly at national rate

National avg

100%

4005 of 4005 cities

City Map

Chromium-6 data across Ohio

Each dot is a city with UCMR 3 chromium-6 data. Detected cities are shown; there is no federal MCL — California's 10 µg/L limit is used as a reference. Size reflects population served.

Worst Offenders

Top 10 cities by chromium-6 level in Ohio

Highest Chromium-6 levels (µg/L)

All Cities

All Ohio cities ranked by chromium-6 level

#	City	Level	Detected?	Violations	Grade
1	Galion	3.20 µg/L	Detected	18	B-
2	Clyde	2.44 µg/L	Detected	0	B+
3	Fremont	1.80 µg/L	Detected	44	B-
4	Norwalk	1.60 µg/L	Detected	12	B+
5	Bowling Green	1.50 µg/L	Detected	85	F
6	Niles	1.50 µg/L	Detected	1	B
7	Attica	1.45 µg/L	Detected	32	C-
8	Cuyahoga Falls	1.37 µg/L	Detected	3	B-
9	Youngstown	1.30 µg/L	Detected	3	C
10	Ravenna	1.13 µg/L	Detected	3	C
11	Barnesville	1.11 µg/L	Detected	14	C
12	Salem	1.00 µg/L	Detected	11	C+
13	Celina	0.88 µg/L	Detected	45	B-
14	Delaware	0.75 µg/L	Detected	5	B
15	Defiance	0.65 µg/L	Detected	171	F
16	Findlay	0.59 µg/L	Detected	6	A-
17	Jamestown	0.58 µg/L	Detected	4	B
18	Dayton	0.50 µg/L	Detected	43	F
19	Aurora	0.49 µg/L	Detected	0	A-
20	Bexley	0.46 µg/L	Detected	16	C
21	Monroe	0.45 µg/L	Detected	2	B
22	Hamilton	0.41 µg/L	Detected	5	B-
23	Fairfield	0.40 µg/L	Detected	9	B
24	Lakewood	0.39 µg/L	Detected	0	B+
25	Williamsport	0.39 µg/L	Detected	31	C-
26	Greenville	0.39 µg/L	Detected	4	A-
27	Fostoria	0.36 µg/L	Detected	32	F
28	Archbold	0.36 µg/L	Detected	16	B
29	Columbus	0.35 µg/L	Detected	56	F
30	Medina	0.35 µg/L	Detected	15	C+
31	Sidney	0.33 µg/L	Detected	5	B+
32	Sylvania	0.32 µg/L	Detected	0	A-
33	Ashland	0.32 µg/L	Detected	2	B+
34	Lucasville	0.32 µg/L	Detected	3	A-
35	Conneaut	0.31 µg/L	Detected	6	B+
36	Marysville	0.30 µg/L	Detected	16	B+
37	Springfield	0.30 µg/L	Detected	42	F
38	Trenton	0.30 µg/L	Detected	10	B-
39	Mcdermott	0.29 µg/L	Detected	2	A
40	Marion	0.28 µg/L	Detected	9	B-
41	Lima	0.28 µg/L	Detected	16	F
42	Van Wert	0.28 µg/L	Detected	47	C
43	Pataskala	0.28 µg/L	Detected	4	B+
44	Toledo	0.26 µg/L	Detected	13	B
45	Kettering	0.26 µg/L	Detected	14	C
46	Massillon	0.25 µg/L	Detected	13	D+
47	Glenford	0.25 µg/L	Detected	3	B+
48	Piqua	0.24 µg/L	Detected	12	B
49	Wilmington	0.24 µg/L	Detected	26	B
50	Painesville	0.24 µg/L	Detected	0	B+
51	Newark	0.24 µg/L	Detected	6	B-
52	Maumee	0.24 µg/L	Detected	6	B-
53	Ripley	0.23 µg/L	Detected	1	A-
54	Berea	0.23 µg/L	Detected	1	B+
55	Chagrin Falls	0.23 µg/L	Detected	1	C
56	Whitehouse	0.23 µg/L	Detected	8	B
57	Cincinnati	0.22 µg/L	Detected	10	F
58	Napoleon	0.22 µg/L	Detected	20	A-
59	Coshocton	0.21 µg/L	Detected	13	B+
60	Bucyrus	0.21 µg/L	Detected	3	B
61	Mount Orab	0.21 µg/L	Detected	2	A-
62	Cleveland	0.20 µg/L	Detected	2	A-
63	Avon	0.20 µg/L	Detected	1	A-
64	Bedford	0.20 µg/L	Detected	0	A
65	Kent	0.20 µg/L	Detected	36	F
66	Struthers	0.18 µg/L	Detected	1	B+
67	Reynoldsburg	0.18 µg/L	Detected	0	B+
68	Ashtabula	0.18 µg/L	Detected	3	B+
69	Marietta	0.18 µg/L	Detected	11	F
70	Oregon	0.18 µg/L	Detected	1	B+
71	Heath	0.17 µg/L	Detected	2	A-
72	Mentor	0.16 µg/L	Detected	6	B-
73	Lagrange	0.16 µg/L	Detected	10	C
74	Tallmadge	0.16 µg/L	Detected	1	B
75	New Philadelphia	0.16 µg/L	Detected	4	B
76	Wellsville	0.16 µg/L	Detected	3	C+
77	Vandalia	0.15 µg/L	Detected	10	B+
78	Port Clinton	0.15 µg/L	Detected	46	D+
79	Girard	0.15 µg/L	Detected	0	B+
80	Lebanon	0.14 µg/L	Detected	28	D
81	Wadsworth	0.13 µg/L	Detected	0	B+
82	Cedarville	0.13 µg/L	Detected	1	B+
83	Steubenville	0.13 µg/L	Detected	30	F
84	Jefferson	0.12 µg/L	Detected	1	B
85	Amherst	0.12 µg/L	Detected	0	B+
86	Lorain	0.11 µg/L	Detected	15	B+
87	Stow	0.11 µg/L	Detected	4	C+
88	Sandusky	0.11 µg/L	Detected	6	A-
89	Avon Lake	0.11 µg/L	Detected	2	A-
90	Ironton	0.10 µg/L	Detected	12	C-
91	Huron	0.10 µg/L	Detected	13	C+
92	North Ridgeville	0.10 µg/L	Detected	1	B
93	N Canton	0.09 µg/L	Detected	0	A-
94	East Liverpool	0.09 µg/L	Detected	14	B
95	Franklin	0.08 µg/L	Detected	2	B+
96	Oak Hill	0.08 µg/L	Detected	9	B-
97	Portsmouth	0.08 µg/L	Detected	1	B
98	Vermilion	0.07 µg/L	Detected	7	B+
99	Alliance	0.07 µg/L	Detected	17	B+
100	Tipp City	0.07 µg/L	Detected	0	C+
101	Camden	0.07 µg/L	Detected	1	B+
102	Cleves	0.07 µg/L	Detected	1	A-
103	Mount Vernon	0.07 µg/L	Detected	3	B+
104	Norwood	0.07 µg/L	Detected	3	B+
105	Loveland	0.06 µg/L	Detected	0	B+
106	St Marys	0.06 µg/L	Detected	1	B
107	Urbana	0.06 µg/L	Detected	24	C+
108	Reading	0.06 µg/L	Detected	3	B
109	West Union	0.06 µg/L	Detected	3	B
110	Morrow	0.06 µg/L	Detected	7	B-
111	Englewood	0.06 µg/L	Detected	1	A-
112	Rossburg	0.05 µg/L	Detected	0	B+
113	Batavia	0.05 µg/L	Detected	2	B+
114	Franklin Furnace	0.05 µg/L	Detected	8	D
115	Cambridge	0.05 µg/L	Detected	86	C-
116	Gallipolis	0.05 µg/L	Detected	3	B
117	Waterford	0.05 µg/L	Detected	5	C+
118	Springboro	0.04 µg/L	Detected	4	B+
119	Greenfield	0.04 µg/L	Detected	3	A-
120	Huber Heights	0.04 µg/L	Detected	4	A-
121	Circleville	0.04 µg/L	Detected	5	B
122	Little Hocking	0.04 µg/L	Detected	0	B+
123	Warren	0.04 µg/L	Detected	62	F
124	New Richmond	0.04 µg/L	Detected	0	B-
125	Canton	0.04 µg/L	Detected	2	B-
126	Mansfield	0.04 µg/L	Detected	37	F
127	Norton	0.04 µg/L	Detected	17	A-
128	Wooster	0.04 µg/L	Detected	14	F
129	Long Bottom	0.03 µg/L	Detected	1	A
130	Xenia	0.03 µg/L	Detected	1	A-
131	Zanesville	0.03 µg/L	Detected	7	D+
132	Vienna	0.03 µg/L	Detected	9	B

FAQ

Frequently asked questions about chromium-6 in Ohio

Is chromium-6 in Ohio tap water dangerous?

Chromium-6 (hexavalent chromium) is a potential human carcinogen. There is currently no federal MCL — California's 10 µg/L limit is the most protective US standard. 132 cities in Ohio had detectable chromium-6 in UCMR 3 testing (2013–2015). Reverse osmosis is the most effective removal method.

Where does chromium-6 come from in Ohio water?

Chromium-6 enters water supplies from two main sources: natural weathering of chromium-containing rock formations (especially in the Southwest and parts of the Midwest) and industrial discharge from steel mills, chrome plating, and coal ash sites. Groundwater systems are more commonly affected by natural sources, while surface water systems near industrial areas face pollution-related risks.

How can I filter chromium-6 from my water in Ohio?

Reverse osmosis (RO) systems are the most effective, removing over 95% of chromium-6. Some high-quality activated alumina or anion exchange filters also provide significant reduction. Standard carbon filters and pitcher filters are generally NOT effective against chromium-6. Look for filters certified by NSF International against NSF/ANSI 58 (for RO systems).

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