Nitrate Contamination

Nitrate in Illinois Drinking Water

Ranked by nitrate violation count · Data from EPA SDWIS & UCMR

255

Cities Tested

255

Has Violations

100%

% Has Violations

3.4 violations

State Avg

▼ 0% vs national

vs National

695

Health Violations

Analysis

Nitrate in Illinois: what the data shows

Illinois has 255 cities with nitrate-related violations. The EPA MCL for nitrate is 10 mg/L (measured as nitrogen). The state has 255 cities with at least one nitrate violation. Nitrate is the most common groundwater contaminant in the United States. It enters water supplies primarily through agricultural fertilizer runoff, septic system leaching, and animal feedlot operations. Rural and agricultural communities face the highest risk. The primary acute health concern is methemoglobinemia ("blue baby syndrome") in infants under six months. Emerging research also links chronic nitrate exposure to thyroid disease, certain cancers, and adverse birth outcomes. Reverse osmosis, ion exchange, and distillation can remove nitrate from drinking water — standard carbon filters do not.

Comparison

Cities exceeding 10 mg/L EPA MCL

Illinois

100%

255 of 255 cities

← = Exactly at national rate

National avg

100%

8001 of 8001 cities

City Map

Nitrate data across Illinois

Each dot is a city with nitrate violation data. Cities with at least one nitrate-related violation are highlighted. Size reflects population served.

Worst Offenders

Top 10 cities by nitrate level in Illinois

Highest Nitrate levels (violations)

All Cities

All Illinois cities ranked by nitrate level

#	City	Level	Violations?	Violations	Grade
1	Georgetown	50 violations	Yes	50	B
2	Blue Mound	25 violations	Yes	26	C
3	Joliet	24 violations	Yes	131	F
4	Decatur	22 violations	Yes	28	B
5	Steeleville	20 violations	Yes	24	D+
6	Momence	18 violations	Yes	11	D+
7	Mount Zion	17 violations	Yes	29	B-
8	Danville	16 violations	Yes	24	B
9	Arenzville	16 violations	Yes	15	A-
10	Chrisman	15 violations	Yes	36	F
11	Kankakee	14 violations	Yes	40	F
12	Bloomington	13 violations	Yes	21	F
13	Rockford	12 violations	Yes	43	F
14	Streator	11 violations	Yes	14	A-
15	Pontiac	11 violations	Yes	10	C
16	Westville	11 violations	Yes	13	B+
17	Catlin	11 violations	Yes	11	A-
18	Wheaton	10 violations	Yes	2	B-
19	Mundelein	10 violations	Yes	22	F
20	Macomb	10 violations	Yes	39	D
21	Sandwich	10 violations	Yes	10	B
22	Sherrard	10 violations	Yes	14	B
23	Northbrook	9 violations	Yes	55	D
24	Marion	9 violations	Yes	29	D
25	Bridgeport	9 violations	Yes	12	B-
26	St Rose	8 violations	Yes	8	D
27	Valrico	8 violations	Yes	4	C+
28	Peru	7 violations	Yes	92	F
29	Paris	7 violations	Yes	12	A
30	Galena	7 violations	Yes	17	D+
31	Tampa	7 violations	Yes	8	B+
32	Malta	7 violations	Yes	18	D
33	New Boston	7 violations	Yes	6	A
34	Waynesville	7 violations	Yes	25	C+
35	Skokie	6 violations	Yes	9	C-
36	Mchenry	6 violations	Yes	57	F
37	Morris	6 violations	Yes	74	F
38	Chandlerville	6 violations	Yes	6	B+
39	Pembroke	6 violations	Yes	0	B-
40	Chicago	5 violations	Yes	68	F
41	Darien	5 violations	Yes	6	C+
42	Lindenhurst	5 violations	Yes	0	B+
43	Eureka	5 violations	Yes	20	B
44	Silvis	5 violations	Yes	14	F
45	Coal Valley	5 violations	Yes	12	F
46	Hudson	5 violations	Yes	5	B+
47	Capron	5 violations	Yes	1	A-
48	Roseville	5 violations	Yes	11	A-
49	Shannon	5 violations	Yes	34	C
50	Godfrey	4 violations	Yes	22	C+
51	Machesney Park	4 violations	Yes	4	B
52	East Peoria	4 violations	Yes	133	F
53	Dixon	4 violations	Yes	57	C
54	Lincoln	4 violations	Yes	8	F
55	Rock Falls	4 violations	Yes	8	B
56	Geneseo	4 violations	Yes	124	F
57	Marseilles	4 violations	Yes	116	D
58	Lawrenceville	4 violations	Yes	6	C+
59	White Hall	4 violations	Yes	12	C+
60	Sumner	4 violations	Yes	6	B+
61	Assumption	4 violations	Yes	4	C+
62	Towanda	4 violations	Yes	4	B-
63	Hutsonville	4 violations	Yes	5	A-
64	Saint Francisville	4 violations	Yes	0	C+
65	Secor	4 violations	Yes	12	D
66	Lyndon	4 violations	Yes	2	A-
67	Dieterich	3 violations	Yes	7	F
68	Loves Park	3 violations	Yes	35	B
69	Freeport	3 violations	Yes	19	B-
70	Richton Park	3 violations	Yes	5	F
71	Fox Lake	3 violations	Yes	5	C+
72	St. Charles	3 violations	Yes	17	F
73	Hillsboro	3 violations	Yes	20	B-
74	Hardin	3 violations	Yes	4	A-
75	Byron	3 violations	Yes	1	C+
76	Metamora	3 violations	Yes	10	C
77	East Dubuque	3 violations	Yes	1	A-
78	Apopka	3 violations	Yes	0	B+
79	Barry	3 violations	Yes	3	B+
80	Johnsburg	3 violations	Yes	5	B-
81	Percy	3 violations	Yes	16	B+
82	Mendon	3 violations	Yes	2	A+
83	Shipman	3 violations	Yes	15	A-
84	Congerville	3 violations	Yes	21	B
85	Aurora	2 violations	Yes	20	D
86	Elk Grove	2 violations	Yes	2	A-
87	Lake In The Hills	2 violations	Yes	4	A-
88	Batavia	2 violations	Yes	33	B+
89	Blue Island	2 violations	Yes	19	C
90	Oak Brook	2 violations	Yes	8	D
91	Morton	2 violations	Yes	13	B-
92	Rantoul	2 violations	Yes	54	D
93	Antioch	2 violations	Yes	6	C-
94	Minooka	2 violations	Yes	6	A-
95	Sugar Grove	2 violations	Yes	7	A-
96	Salem	2 violations	Yes	7	C
97	Waterloo	2 violations	Yes	1	C
98	Steger	2 violations	Yes	8	B+
99	Lake Bluff	2 violations	Yes	18	C+
100	Wilmington	2 violations	Yes	10	C+
101	Monee	2 violations	Yes	2	B
102	Virden	2 violations	Yes	15	A-
103	Athens	2 violations	Yes	0	B+
104	Red Bud	2 violations	Yes	3	B-
105	South Jacksonville	2 violations	Yes	3	C-
106	Casey	2 violations	Yes	16	B
107	Oakwood	2 violations	Yes	18	A-
108	Diamond	2 violations	Yes	20	A-
109	Henry	2 violations	Yes	3	A-
110	Long Grove	2 violations	Yes	51	C-
111	Cordova	2 violations	Yes	2	B-
112	Erie	2 violations	Yes	4	C+
113	Milford	2 violations	Yes	5	C+
114	Waterman	2 violations	Yes	17	A-
115	North Utica	2 violations	Yes	25	B
116	Griggsville	2 violations	Yes	0	A-
117	South Pekin	2 violations	Yes	0	B+
118	Pearl City	2 violations	Yes	0	D
119	Tonica	2 violations	Yes	16	A
120	Creston	2 violations	Yes	0	A-
121	Williamsfield	2 violations	Yes	5	A-
122	Godley	2 violations	Yes	0	A-
123	Andover	2 violations	Yes	0	A-
124	West Union	2 violations	Yes	0	A-
125	London Mills	2 violations	Yes	1	A
126	Schaumburg	1 violations	Yes	17	B+
127	Des Plaines	1 violations	Yes	0	B+
128	Quincy	1 violations	Yes	3	B-
129	Rock Island	1 violations	Yes	5	B-
130	Moline	1 violations	Yes	7	C
131	Lombard	1 violations	Yes	1	A-
132	Crystal Lake	1 violations	Yes	4	A-
133	Saint Charles	1 violations	Yes	3	B+
134	Mattoon	1 violations	Yes	14	B-
135	Wilmette	1 violations	Yes	0	A
136	Lockport	1 violations	Yes	20	F
137	Belvidere	1 violations	Yes	8	A-
138	Zion	1 violations	Yes	1	B
139	South Elgin	1 violations	Yes	28	C
140	Jacksonville	1 violations	Yes	28	B-
141	Yorkville	1 violations	Yes	83	C+
142	Weston	1 violations	Yes	6	A
143	Canton	1 violations	Yes	7	B+
144	Urbana	1 violations	Yes	0	C+
145	Highland	1 violations	Yes	16	B
146	Glen Carbon	1 violations	Yes	0	B
147	Kewanee	1 violations	Yes	34	B
148	Plano	1 violations	Yes	0	B+
149	Winnetka	1 violations	Yes	0	A
150	Warrenville	1 violations	Yes	0	B+
151	Carlinville	1 violations	Yes	74	D
152	La Salle	1 violations	Yes	6	B-
153	Crete	1 violations	Yes	4	B
154	Harvard	1 violations	Yes	3	A
155	Gilberts	1 violations	Yes	0	A-
156	West Dundee	1 violations	Yes	7	A
157	Rockton	1 violations	Yes	31	C
158	Clinton	1 violations	Yes	18	B+
159	Dallas City	1 violations	Yes	1	B+
160	Mount Carmel	1 violations	Yes	11	B
161	Elburn	1 violations	Yes	63	D
162	Milan	1 violations	Yes	28	D
163	Joppa	1 violations	Yes	3	B+
164	Litchfield	1 violations	Yes	5	D+
165	Dekalb	1 violations	Yes	2	A-
166	Metropolis	1 violations	Yes	0	A-
167	Chillicothe	1 violations	Yes	11	D+
168	Winchester	1 violations	Yes	8	B-
169	Beardstown	1 violations	Yes	1	A
170	Coal City	1 violations	Yes	40	D
171	Wonder Lake	1 violations	Yes	6	C+
172	Staunton	1 violations	Yes	21	C+
173	Watseka	1 violations	Yes	9	A-
174	Genoa	1 violations	Yes	4	A
175	Fox River Grove	1 violations	Yes	10	B
176	Breese	1 violations	Yes	0	C+
177	Beecher	1 violations	Yes	0	A-
178	Smithton	1 violations	Yes	7	B
179	Morrison	1 violations	Yes	3	B+
180	Rochester	1 violations	Yes	0	A-
181	Gillespie	1 violations	Yes	14	C+
182	Vienna	1 violations	Yes	17	B
183	Le Roy	1 violations	Yes	12	D
184	Fulton	1 violations	Yes	6	B
185	Lakemoor	1 violations	Yes	0	B+
186	Marquette Heights	1 violations	Yes	0	A
187	Menard	1 violations	Yes	1	F
188	Oak Brook Terr	1 violations	Yes	7	B+
189	Tamms	1 violations	Yes	0	B+
190	Grayslake	1 violations	Yes	7	B+
191	Farmington	1 violations	Yes	24	A-
192	New Berlin	1 violations	Yes	28	D
193	Prospect Heights	1 violations	Yes	9	B+
194	Nokomis	1 violations	Yes	7	A
195	Elwood	1 violations	Yes	2	A-
196	Groveland	1 violations	Yes	0	A+
197	Prophetstown	1 violations	Yes	2	B
198	Carrier Mills	1 violations	Yes	3	A-
199	Elmwood	1 violations	Yes	9	A
200	Port Byron	1 violations	Yes	4	B-
201	Windsor	1 violations	Yes	11	C-
202	Lexington	1 violations	Yes	2	B+
203	Chenoa	1 violations	Yes	19	F
204	East Chicago Heights	1 violations	Yes	19	B-
205	Gilman	1 violations	Yes	1	B+
206	Atlanta	1 violations	Yes	8	B+
207	Neoga	1 violations	Yes	32	B+
208	Earlville	1 violations	Yes	0	A
209	Grayville	1 violations	Yes	0	A-
210	Warsaw	1 violations	Yes	12	A-
211	Kincaid	1 violations	Yes	4	B+
212	Loda	1 violations	Yes	1	B
213	North Pekin	1 violations	Yes	1	A-
214	Murrayville	1 violations	Yes	0	B+
215	Payson	1 violations	Yes	3	A-
216	Danvers	1 violations	Yes	48	B-
217	Tower Lakes	1 violations	Yes	1	B-
218	Ashland	1 violations	Yes	10	A-
219	Wyoming	1 violations	Yes	8	B+
220	Hanna City	1 violations	Yes	6	A
221	Downs	1 violations	Yes	8	B
222	Hillcrest	1 violations	Yes	4	B+
223	Martinsville	1 violations	Yes	3	B+
224	Nauvoo	1 violations	Yes	20	B+
225	Waverly	1 violations	Yes	22	A
226	Toulon	1 violations	Yes	13	B
227	Oquawka	1 violations	Yes	0	A+
228	Royalton	1 violations	Yes	0	B
229	Tower Hill	1 violations	Yes	1	B+
230	Chebanse	1 violations	Yes	6	B+
231	Meredosia	1 violations	Yes	0	A-
232	Valrico	1 violations	Yes	0	A-
233	Washburn	1 violations	Yes	0	B+
234	Lovington	1 violations	Yes	1	B-
235	Hennepin	1 violations	Yes	7	A-
236	Raymond	1 violations	Yes	0	A+
237	Wataga	1 violations	Yes	3	B
238	Argenta	1 violations	Yes	0	B
239	Franklin Grove	1 violations	Yes	0	A-
240	Tallula	1 violations	Yes	0	A-
241	Alexis	1 violations	Yes	3	B+
242	Oakland	1 violations	Yes	0	B+
243	Vermont	1 violations	Yes	24	D
244	Ashkum	1 violations	Yes	11	C+
245	Taylor Ridge	1 violations	Yes	6	B+
246	Kirkwood	1 violations	Yes	27	B+
247	Mathersville	1 violations	Yes	0	A
248	Coffeen	1 violations	Yes	7	B
249	Deer Creek	1 violations	Yes	1	A-
250	Ashmore	1 violations	Yes	0	C
251	Ursa	1 violations	Yes	1	A
252	Keyesport	1 violations	Yes	9	A-
253	Nebo	1 violations	Yes	1	D
254	Blandinsville	1 violations	Yes	6	A
255	Grand Ridge	1 violations	Yes	26	B+

FAQ

Frequently asked questions about nitrate in Illinois

Is nitrate in Illinois tap water dangerous?

Yes — 255 cities in Illinois have nitrate-related violations. The EPA MCL is 10 mg/L. Nitrate is especially dangerous for infants under six months, where it can cause methemoglobinemia ("blue baby syndrome"). Adults face lower acute risk, but chronic exposure is linked to thyroid disease and certain cancers.

How can I remove nitrate from my drinking water?

Reverse osmosis, ion exchange, and distillation are effective at removing nitrate. Standard carbon filters (including most pitcher and faucet-mount filters) do NOT remove nitrate. If you rely on a private well in an agricultural area, have your water tested annually for nitrate.

What causes high nitrate levels in Illinois water?

Nitrate contamination comes primarily from agricultural fertilizer runoff, septic system leaching, and animal feedlot operations. Rural communities near intensive farming are most at risk. Shallow wells are particularly vulnerable. Heavy rainfall can spike nitrate levels as it washes fertilizer into groundwater and surface water supplies.

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