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

202

Cities Tested

202

Detected

100%

% Detected

0.51 µg/L

State Avg

▼ 0% vs national

vs National

687

Health Violations

Analysis

Chromium-6 in Illinois: what the data shows

Illinois has 202 cities with chromium-6 data from the EPA's UCMR 3 program (2013–2015). Hexavalent chromium (Cr VI) was detected in 202 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 0.51 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%

202 of 202 cities

← = Exactly at national rate

National avg

100%

3934 of 3934 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	Wood River	1.31 µg/L	Detected	0	B+
25	Edwardsville	1.23 µg/L	Detected	18	D+
26	Benton	1.20 µg/L	Detected	5	D
27	Marion	1.18 µg/L	Detected	29	D
28	Carterville	1.11 µg/L	Detected	3	C+
29	North Pekin	1.11 µg/L	Detected	1	A-
30	Rockford	1.10 µg/L	Detected	43	F
31	Tamaroa	1.10 µg/L	Detected	0	A-
32	Herrin	1.07 µg/L	Detected	0	C+
33	Mount Vernon	1.05 µg/L	Detected	2	B+
34	Park Forest	1.00 µg/L	Detected	2	A
35	Troy	0.91 µg/L	Detected	3	A-
36	Montgomery	0.66 µg/L	Detected	4	A-
37	Machesney Park	0.65 µg/L	Detected	4	B
38	Peoria	0.60 µg/L	Detected	5	C-
39	Wauconda	0.58 µg/L	Detected	3	A
40	Bartlett	0.56 µg/L	Detected	49	B-
41	Elgin	0.53 µg/L	Detected	9	C-
42	Sleepy Hollow	0.51 µg/L	Detected	4	A-
43	Nashville	0.39 µg/L	Detected	27	C-
44	Villa Park	0.35 µg/L	Detected	2	A
45	Hazel Crest	0.32 µg/L	Detected	2	B
46	Chatham	0.30 µg/L	Detected	2	A
47	Libertyville	0.30 µg/L	Detected	14	C
48	Westmont	0.29 µg/L	Detected	6	B-
49	Huntley	0.28 µg/L	Detected	15	A
50	Highland Park	0.28 µg/L	Detected	2	B+
51	Deerfield	0.28 µg/L	Detected	4	B
52	Mundelein	0.28 µg/L	Detected	22	F
53	Rantoul	0.28 µg/L	Detected	54	D
54	Darien	0.27 µg/L	Detected	6	C+
55	Freeburg	0.27 µg/L	Detected	7	A-
56	East Peoria	0.27 µg/L	Detected	133	F
57	Bridgeview	0.27 µg/L	Detected	0	A-
58	Galesburg	0.26 µg/L	Detected	1	B
59	Cicero	0.26 µg/L	Detected	3	B
60	Glen Ellyn	0.26 µg/L	Detected	0	A-
61	Franklin Park	0.26 µg/L	Detected	5	B
62	Bensenville	0.26 µg/L	Detected	4	A
63	Palatine	0.25 µg/L	Detected	2	B
64	Schaumburg	0.25 µg/L	Detected	17	B+
65	Park Ridge	0.25 µg/L	Detected	1	B
66	Markham	0.25 µg/L	Detected	7	B
67	Rock Island	0.24 µg/L	Detected	5	B-
68	Evanston	0.24 µg/L	Detected	1	A+
69	Des Plaines	0.24 µg/L	Detected	0	B+
70	Glenview	0.24 µg/L	Detected	3	B+
71	Addison	0.24 µg/L	Detected	0	A
72	Calumet City	0.24 µg/L	Detected	3	C-
73	New Lenox	0.24 µg/L	Detected	7	D+
74	Lisle	0.24 µg/L	Detected	2	A-
75	Blue Island	0.24 µg/L	Detected	19	C
76	Dolton	0.24 µg/L	Detected	2	C
77	Palos Hills	0.24 µg/L	Detected	3	A
78	Riverdale	0.24 µg/L	Detected	6	B+
79	North Chicago	0.24 µg/L	Detected	5	B+
80	Naperville	0.23 µg/L	Detected	0	B+
81	Wheaton	0.23 µg/L	Detected	2	B-
82	Northbrook	0.23 µg/L	Detected	55	D
83	Lombard	0.23 µg/L	Detected	1	A-
84	Hanover Park	0.23 µg/L	Detected	3	A
85	Elmwood Park	0.23 µg/L	Detected	3	B+
86	Maywood	0.23 µg/L	Detected	3	C+
87	Rolling Meadows	0.23 µg/L	Detected	3	A
88	Weston	0.23 µg/L	Detected	6	A
89	Homewood	0.23 µg/L	Detected	2	C
90	Bellwood	0.23 µg/L	Detected	7	B+
91	Alsip	0.23 µg/L	Detected	2	A-
92	Brookfield	0.23 µg/L	Detected	0	A-
93	Forest Park	0.23 µg/L	Detected	2	A-
94	Wood Dale	0.23 µg/L	Detected	0	A-
95	River Forest	0.23 µg/L	Detected	1	B+
96	Glenwood	0.23 µg/L	Detected	0	B+
97	Lake Forest	0.23 µg/L	Detected	58	B-
98	Burr Ridge	0.23 µg/L	Detected	0	A
99	Chicago	0.22 µg/L	Detected	68	F
100	Bolingbrook	0.22 µg/L	Detected	2	A
101	Godfrey	0.22 µg/L	Detected	22	C+
102	Orland Park	0.22 µg/L	Detected	0	A-
103	Berwyn	0.22 µg/L	Detected	3	A-
104	Tinley Park	0.22 µg/L	Detected	0	B+
105	Hoffman Estates	0.22 µg/L	Detected	7	A+
106	Downers Grove	0.22 µg/L	Detected	2	A
107	Elmhurst	0.22 µg/L	Detected	2	A-
108	Mount Prospect	0.22 µg/L	Detected	1	B+
109	Carol Stream	0.22 µg/L	Detected	1	A-
110	Streamwood	0.22 µg/L	Detected	2	A-
111	Woodridge	0.22 µg/L	Detected	2	A-
112	Burbank (South Stickney)	0.22 µg/L	Detected	7	B+
113	Chicago Heights	0.22 µg/L	Detected	0	B+
114	Roselle	0.22 µg/L	Detected	2	A-
115	Round Lake	0.22 µg/L	Detected	3	A-
116	Matteson	0.22 µg/L	Detected	1	B
117	Hinsdale	0.22 µg/L	Detected	0	A
118	Westchester	0.22 µg/L	Detected	2	B
119	Oak Brook	0.22 µg/L	Detected	8	D
120	North Lake	0.22 µg/L	Detected	1	B+
121	Summit	0.22 µg/L	Detected	1	B+
122	River Grove	0.22 µg/L	Detected	3	A-
123	Waukegan	0.21 µg/L	Detected	5	B+
124	Justice	0.21 µg/L	Detected	0	A-
125	Skokie	0.21 µg/L	Detected	9	C-
126	Oak Lawn	0.21 µg/L	Detected	2	B
127	Oak Park	0.21 µg/L	Detected	2	A
128	Glendale Heights	0.21 µg/L	Detected	1	A
129	Gurnee	0.21 µg/L	Detected	4	A
130	Niles	0.21 µg/L	Detected	3	B
131	Wilmette	0.21 µg/L	Detected	0	A
132	South Holland	0.21 µg/L	Detected	5	B-
133	Evergreen Park	0.21 µg/L	Detected	0	B+
134	La Grange	0.21 µg/L	Detected	1	B
135	Palos Heights	0.21 µg/L	Detected	1	A-
136	Norridge	0.21 µg/L	Detected	0	A-
137	Midlothian	0.21 µg/L	Detected	5	A-
138	Minooka	0.21 µg/L	Detected	6	A-
139	Schiller Park	0.21 µg/L	Detected	7	A-
140	Worth	0.21 µg/L	Detected	3	A
141	Lyons	0.21 µg/L	Detected	7	A-
142	Elk Grove	0.21 µg/L	Detected	2	A-
143	La Grange Park	0.21 µg/L	Detected	2	A
144	Zion	0.20 µg/L	Detected	1	B
145	Arlington Heights	0.20 µg/L	Detected	1	B-
146	Romeoville	0.20 µg/L	Detected	17	A-
147	Wheeling	0.20 µg/L	Detected	5	A+
148	Harvey	0.20 µg/L	Detected	1	B
149	Melrose Park	0.20 µg/L	Detected	6	C
150	Freeport	0.20 µg/L	Detected	19	B-
151	Mokena	0.20 µg/L	Detected	2	A
152	Hickory Hills	0.20 µg/L	Detected	1	A
153	Chicago Ridge	0.20 µg/L	Detected	1	A-
154	Lincolnwood	0.20 µg/L	Detected	1	B+
155	Westhaven	0.20 µg/L	Detected	3	A+
156	Buffalo Grove	0.20 µg/L	Detected	1	A
157	Country Club Hills	0.20 µg/L	Detected	0	A-
158	Crestwood	0.19 µg/L	Detected	0	B
159	Round Lake Beach	0.19 µg/L	Detected	3	B+
160	Plainfield	0.19 µg/L	Detected	23	B-
161	Morton Grove	0.19 µg/L	Detected	2	B-
162	Oak Forest	0.19 µg/L	Detected	0	B+
163	Winnetka	0.18 µg/L	Detected	0	A
164	Lansing	0.18 µg/L	Detected	2	B
165	Grays Lake	0.17 µg/L	Detected	6	A
166	O Fallon	0.17 µg/L	Detected	17	A-
167	Belvidere	0.13 µg/L	Detected	8	A-
168	Bethalto	0.11 µg/L	Detected	0	A-
169	Murphysboro	0.10 µg/L	Detected	8	B
170	Granite City	0.10 µg/L	Detected	0	B+
171	Kewanee	0.10 µg/L	Detected	34	B
172	East St Louis	0.09 µg/L	Detected	1	B+
173	Morton	0.09 µg/L	Detected	13	B-
174	East Moline	0.09 µg/L	Detected	18	D+
175	Lake In The Hills	0.09 µg/L	Detected	4	A-
176	Ottawa	0.08 µg/L	Detected	62	F
177	Plano	0.08 µg/L	Detected	0	B+
178	Alton	0.08 µg/L	Detected	1	B
179	South Elgin	0.07 µg/L	Detected	28	C
180	Saint Charles	0.07 µg/L	Detected	3	B+
181	Caseyville	0.07 µg/L	Detected	3	B+
182	Lake Zurich	0.06 µg/L	Detected	35	B+
183	Salem	0.05 µg/L	Detected	7	C
184	Robinson	0.05 µg/L	Detected	0	A-
185	Centralia	0.04 µg/L	Detected	2	B
186	Lockport	0.04 µg/L	Detected	20	F
187	Yorkville	0.04 µg/L	Detected	83	C+
188	Dixon	0.04 µg/L	Detected	57	C
189	Canton	0.04 µg/L	Detected	7	B+
190	Coleta	0.04 µg/L	Detected	1	A-
191	Lindenhurst	0.04 µg/L	Detected	0	B+
192	Western Springs	0.04 µg/L	Detected	2	B
193	St. Charles	0.04 µg/L	Detected	17	F
194	Rochelle	0.04 µg/L	Detected	11	A
195	Mascoutah	0.04 µg/L	Detected	6	A-
196	Algonquin	0.04 µg/L	Detected	6	A-
197	Glen Carbon	0.03 µg/L	Detected	0	B
198	Carbondale	0.03 µg/L	Detected	26	D
199	Streator	0.03 µg/L	Detected	14	A-
200	Shorewood	0.03 µg/L	Detected	4	A-
201	North Aurora	0.03 µg/L	Detected	27	A-
202	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. 202 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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