Chromium-6 Contamination

Chromium-6 in Illinois Drinking Water

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

204

Cities Tested

204

Detected

100%

% Detected

0.52 µg/L

State Avg

▼ 0% vs national

vs National

695

Health Violations

Analysis

Chromium-6 in Illinois: what the data shows

Illinois has 204 cities with chromium-6 data from the EPA's UCMR 3 program (2013–2015). Hexavalent chromium (Cr VI) was detected in 204 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 0.52 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)

Illinois

100%

204 of 204 cities

← = Exactly at national rate

National avg

100%

4005 of 4005 cities

City Map

Chromium-6 data across Illinois

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 Illinois

Highest Chromium-6 levels (µg/L)

All Cities

All Illinois cities ranked by chromium-6 level

#	City	Level	Detected?	Violations	Grade
1	Eureka	4.50 µg/L	Detected	20	B
2	Collinsville	3.75 µg/L	Detected	12	C-
3	Jerseyville	3.44 µg/L	Detected	6	A-
4	Aurora	3.30 µg/L	Detected	20	D
5	Jacksonville	3.27 µg/L	Detected	28	B-
6	Normal	3.10 µg/L	Detected	3	D+
7	Taylorville	2.96 µg/L	Detected	0	A-
8	West Chicago	2.71 µg/L	Detected	22	A
9	Kankakee	2.40 µg/L	Detected	40	F
10	Bloomington	2.40 µg/L	Detected	21	F
11	Quincy	2.35 µg/L	Detected	3	B-
12	Waverly	2.17 µg/L	Detected	22	A
13	Decatur	2.05 µg/L	Detected	28	B
14	Danville	2.00 µg/L	Detected	24	B
15	Moline	1.97 µg/L	Detected	7	C
16	Charleston	1.91 µg/L	Detected	10	C+
17	Springfield	1.80 µg/L	Detected	3	D
18	Dieterich	1.78 µg/L	Detected	7	F
19	Macomb	1.70 µg/L	Detected	39	D
20	Mattoon	1.70 µg/L	Detected	14	B-
21	Pekin	1.60 µg/L	Detected	1	D+
22	Effingham	1.41 µg/L	Detected	2	A-
23	Champaign	1.40 µg/L	Detected	0	A
24	Urbana	1.33 µg/L	Detected	0	C+
25	Wood River	1.31 µg/L	Detected	0	B+
26	Edwardsville	1.23 µg/L	Detected	18	D+
27	Benton	1.20 µg/L	Detected	5	D
28	Marion	1.18 µg/L	Detected	29	D
29	Carterville	1.11 µg/L	Detected	3	C+
30	North Pekin	1.11 µg/L	Detected	1	A-
31	Rockford	1.10 µg/L	Detected	43	F
32	Tamaroa	1.10 µg/L	Detected	0	A-
33	Herrin	1.07 µg/L	Detected	0	C+
34	Mount Vernon	1.05 µg/L	Detected	2	B+
35	Park Forest	1.00 µg/L	Detected	2	A
36	Troy	0.91 µg/L	Detected	3	A-
37	Montgomery	0.66 µg/L	Detected	4	A-
38	Machesney Park	0.65 µg/L	Detected	4	B
39	Peoria	0.60 µg/L	Detected	5	D+
40	Wauconda	0.58 µg/L	Detected	3	A
41	Bartlett	0.56 µg/L	Detected	49	B-
42	Elgin	0.53 µg/L	Detected	9	C-
43	Sleepy Hollow	0.51 µg/L	Detected	4	A-
44	Nashville	0.39 µg/L	Detected	27	C-
45	Villa Park	0.35 µg/L	Detected	2	A
46	Hazel Crest	0.32 µg/L	Detected	2	B
47	Chatham	0.30 µg/L	Detected	2	A
48	Libertyville	0.30 µg/L	Detected	14	C
49	Westmont	0.29 µg/L	Detected	6	B-
50	Huntley	0.28 µg/L	Detected	15	A
51	Highland Park	0.28 µg/L	Detected	2	B+
52	Deerfield	0.28 µg/L	Detected	4	B
53	Mundelein	0.28 µg/L	Detected	22	F
54	Rantoul	0.28 µg/L	Detected	54	D
55	Darien	0.27 µg/L	Detected	6	C+
56	Freeburg	0.27 µg/L	Detected	7	A-
57	East Peoria	0.27 µg/L	Detected	133	F
58	Bridgeview	0.27 µg/L	Detected	0	A-
59	Galesburg	0.26 µg/L	Detected	1	B
60	Cicero	0.26 µg/L	Detected	3	B
61	Glen Ellyn	0.26 µg/L	Detected	0	A-
62	Franklin Park	0.26 µg/L	Detected	5	B
63	Bensenville	0.26 µg/L	Detected	4	A
64	Palatine	0.25 µg/L	Detected	2	B
65	Schaumburg	0.25 µg/L	Detected	17	B+
66	Park Ridge	0.25 µg/L	Detected	1	B
67	Vernon Hills	0.25 µg/L	Detected	4	B+
68	Markham	0.25 µg/L	Detected	7	B
69	Rock Island	0.24 µg/L	Detected	5	B-
70	Evanston	0.24 µg/L	Detected	1	A+
71	Des Plaines	0.24 µg/L	Detected	0	B+
72	Glenview	0.24 µg/L	Detected	3	B+
73	Addison	0.24 µg/L	Detected	0	A
74	Calumet City	0.24 µg/L	Detected	3	C-
75	New Lenox	0.24 µg/L	Detected	7	D+
76	Lisle	0.24 µg/L	Detected	2	A-
77	Blue Island	0.24 µg/L	Detected	19	C
78	Dolton	0.24 µg/L	Detected	2	C
79	Palos Hills	0.24 µg/L	Detected	3	A
80	Riverdale	0.24 µg/L	Detected	6	B+
81	North Chicago	0.24 µg/L	Detected	5	B+
82	Naperville	0.23 µg/L	Detected	0	B+
83	Wheaton	0.23 µg/L	Detected	2	B-
84	Lombard	0.23 µg/L	Detected	1	A-
85	Northbrook	0.23 µg/L	Detected	55	D
86	Hanover Park	0.23 µg/L	Detected	3	A
87	Elmwood Park	0.23 µg/L	Detected	3	B+
88	Maywood	0.23 µg/L	Detected	3	C+
89	Rolling Meadows	0.23 µg/L	Detected	3	A
90	Forest Park	0.23 µg/L	Detected	2	A-
91	Weston	0.23 µg/L	Detected	6	A
92	Homewood	0.23 µg/L	Detected	2	C
93	Bellwood	0.23 µg/L	Detected	7	B+
94	Alsip	0.23 µg/L	Detected	2	A-
95	Brookfield	0.23 µg/L	Detected	0	A-
96	Wood Dale	0.23 µg/L	Detected	0	A-
97	River Forest	0.23 µg/L	Detected	1	B+
98	Glenwood	0.23 µg/L	Detected	0	B+
99	Lake Forest	0.23 µg/L	Detected	58	B-
100	Burr Ridge	0.23 µg/L	Detected	0	A
101	Chicago	0.22 µg/L	Detected	68	F
102	Bolingbrook	0.22 µg/L	Detected	2	A
103	Godfrey	0.22 µg/L	Detected	22	C+
104	Orland Park	0.22 µg/L	Detected	0	A-
105	Berwyn	0.22 µg/L	Detected	3	A-
106	Tinley Park	0.22 µg/L	Detected	0	B+
107	Hoffman Estates	0.22 µg/L	Detected	7	A+
108	Downers Grove	0.22 µg/L	Detected	2	A
109	Elmhurst	0.22 µg/L	Detected	2	A-
110	Mount Prospect	0.22 µg/L	Detected	1	B+
111	Carol Stream	0.22 µg/L	Detected	1	A-
112	Streamwood	0.22 µg/L	Detected	2	A-
113	Woodridge	0.22 µg/L	Detected	2	A-
114	Burbank (South Stickney)	0.22 µg/L	Detected	7	B+
115	Chicago Heights	0.22 µg/L	Detected	0	B+
116	Roselle	0.22 µg/L	Detected	2	A-
117	Matteson	0.22 µg/L	Detected	1	B
118	Round Lake	0.22 µg/L	Detected	3	A-
119	Oak Brook	0.22 µg/L	Detected	8	D
120	Hinsdale	0.22 µg/L	Detected	0	A
121	Westchester	0.22 µg/L	Detected	2	B
122	North Lake	0.22 µg/L	Detected	1	B+
123	Summit	0.22 µg/L	Detected	1	B+
124	River Grove	0.22 µg/L	Detected	3	A-
125	Waukegan	0.21 µg/L	Detected	5	B+
126	Justice	0.21 µg/L	Detected	0	A-
127	Skokie	0.21 µg/L	Detected	9	C-
128	Oak Lawn	0.21 µg/L	Detected	2	B
129	Oak Park	0.21 µg/L	Detected	2	A
130	Glendale Heights	0.21 µg/L	Detected	1	A
131	Gurnee	0.21 µg/L	Detected	4	A
132	Niles	0.21 µg/L	Detected	3	B
133	Wilmette	0.21 µg/L	Detected	0	A
134	South Holland	0.21 µg/L	Detected	5	B-
135	Evergreen Park	0.21 µg/L	Detected	0	B+
136	La Grange	0.21 µg/L	Detected	1	B
137	Palos Heights	0.21 µg/L	Detected	1	A-
138	Norridge	0.21 µg/L	Detected	0	A-
139	Midlothian	0.21 µg/L	Detected	5	A-
140	Minooka	0.21 µg/L	Detected	6	A-
141	Schiller Park	0.21 µg/L	Detected	7	A-
142	Worth	0.21 µg/L	Detected	3	A
143	Lyons	0.21 µg/L	Detected	7	A-
144	Elk Grove	0.21 µg/L	Detected	2	A-
145	La Grange Park	0.21 µg/L	Detected	2	A
146	Zion	0.20 µg/L	Detected	1	B
147	Arlington Heights	0.20 µg/L	Detected	1	B-
148	Romeoville	0.20 µg/L	Detected	17	A-
149	Wheeling	0.20 µg/L	Detected	5	A+
150	Harvey	0.20 µg/L	Detected	1	B
151	Melrose Park	0.20 µg/L	Detected	6	C
152	Freeport	0.20 µg/L	Detected	19	B-
153	Mokena	0.20 µg/L	Detected	2	A
154	Hickory Hills	0.20 µg/L	Detected	1	A
155	Chicago Ridge	0.20 µg/L	Detected	1	A-
156	Lincolnwood	0.20 µg/L	Detected	1	B+
157	Westhaven	0.20 µg/L	Detected	3	A+
158	Buffalo Grove	0.20 µg/L	Detected	1	A
159	Country Club Hills	0.20 µg/L	Detected	0	A-
160	Crestwood	0.19 µg/L	Detected	0	B
161	Round Lake Beach	0.19 µg/L	Detected	3	B+
162	Plainfield	0.19 µg/L	Detected	23	B-
163	Morton Grove	0.19 µg/L	Detected	2	B-
164	Oak Forest	0.19 µg/L	Detected	0	B+
165	Winnetka	0.18 µg/L	Detected	0	A
166	Lansing	0.18 µg/L	Detected	2	B
167	Grays Lake	0.17 µg/L	Detected	6	A
168	O Fallon	0.17 µg/L	Detected	17	A-
169	Belvidere	0.13 µg/L	Detected	8	A-
170	Bethalto	0.11 µg/L	Detected	0	A-
171	Granite City	0.10 µg/L	Detected	0	B+
172	Murphysboro	0.10 µg/L	Detected	8	B
173	Kewanee	0.10 µg/L	Detected	34	B
174	East St Louis	0.09 µg/L	Detected	1	B+
175	Morton	0.09 µg/L	Detected	13	B-
176	East Moline	0.09 µg/L	Detected	18	D+
177	Lake In The Hills	0.09 µg/L	Detected	4	A-
178	Ottawa	0.08 µg/L	Detected	62	F
179	Plano	0.08 µg/L	Detected	0	B+
180	Alton	0.08 µg/L	Detected	1	B
181	South Elgin	0.07 µg/L	Detected	28	C
182	Saint Charles	0.07 µg/L	Detected	3	B+
183	Caseyville	0.07 µg/L	Detected	3	B+
184	Lake Zurich	0.06 µg/L	Detected	35	B+
185	Salem	0.05 µg/L	Detected	7	C
186	Robinson	0.05 µg/L	Detected	0	A-
187	Centralia	0.04 µg/L	Detected	2	B
188	Lockport	0.04 µg/L	Detected	20	F
189	Yorkville	0.04 µg/L	Detected	83	C+
190	Dixon	0.04 µg/L	Detected	57	C
191	Canton	0.04 µg/L	Detected	7	B+
192	Coleta	0.04 µg/L	Detected	1	A-
193	Lindenhurst	0.04 µg/L	Detected	0	B+
194	Western Springs	0.04 µg/L	Detected	2	B
195	St. Charles	0.04 µg/L	Detected	17	F
196	Rochelle	0.04 µg/L	Detected	11	A
197	Mascoutah	0.04 µg/L	Detected	6	A-
198	Algonquin	0.04 µg/L	Detected	6	A-
199	Glen Carbon	0.03 µg/L	Detected	0	B
200	Carbondale	0.03 µg/L	Detected	26	D
201	Streator	0.03 µg/L	Detected	14	A-
202	Shorewood	0.03 µg/L	Detected	4	A-
203	North Aurora	0.03 µg/L	Detected	27	A-
204	Pontiac	0.03 µg/L	Detected	10	C

FAQ

Frequently asked questions about chromium-6 in Illinois

Is chromium-6 in Illinois 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. 204 cities in Illinois 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 Illinois 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 Illinois?

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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