Nitrate Contamination

Nitrate in Illinois Drinking Water

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

250

Cities Tested

250

Has Violations

100%

% Has Violations

3.4 violations

State Avg

▼ 0% vs national

vs National

687

Health Violations

Analysis

Nitrate in Illinois: what the data shows

Illinois has 250 cities with nitrate-related violations. The EPA MCL for nitrate is 10 mg/L (measured as nitrogen). The state has 250 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%

250 of 250 cities

← = Exactly at national rate

National avg

100%

7727 of 7727 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	Westville	11 violations	Yes	13	B+
16	Catlin	11 violations	Yes	11	A-
17	Pontiac	11 violations	Yes	10	C
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	Silvis	5 violations	Yes	14	F
44	Eureka	5 violations	Yes	20	B
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	Rock Falls	4 violations	Yes	8	B
55	Geneseo	4 violations	Yes	124	F
56	Marseilles	4 violations	Yes	116	D
57	Lawrenceville	4 violations	Yes	6	C+
58	Lincoln	4 violations	Yes	8	F
59	White Hall	4 violations	Yes	12	C+
60	Assumption	4 violations	Yes	4	C+
61	Sumner	4 violations	Yes	6	B+
62	Towanda	4 violations	Yes	4	B-
63	Hutsonville	4 violations	Yes	5	A-
64	Saint Francisville	4 violations	Yes	0	C+
65	Lyndon	4 violations	Yes	2	A-
66	Dieterich	3 violations	Yes	7	F
67	Freeport	3 violations	Yes	19	B-
68	Loves Park	3 violations	Yes	35	B
69	Richton Park	3 violations	Yes	5	F
70	St. Charles	3 violations	Yes	17	F
71	Hillsboro	3 violations	Yes	20	B-
72	Byron	3 violations	Yes	1	C+
73	Hardin	3 violations	Yes	4	A-
74	Metamora	3 violations	Yes	10	C
75	East Dubuque	3 violations	Yes	1	A-
76	Apopka	3 violations	Yes	0	B+
77	Barry	3 violations	Yes	3	B+
78	Johnsburg	3 violations	Yes	5	B-
79	Percy	3 violations	Yes	16	B+
80	Mendon	3 violations	Yes	2	A+
81	Shipman	3 violations	Yes	15	A-
82	Aurora	2 violations	Yes	20	D
83	Elk Grove	2 violations	Yes	2	A-
84	Lake In The Hills	2 violations	Yes	4	A-
85	Batavia	2 violations	Yes	33	B+
86	Blue Island	2 violations	Yes	19	C
87	Morton	2 violations	Yes	13	B-
88	Antioch	2 violations	Yes	6	C-
89	Rantoul	2 violations	Yes	54	D
90	Oak Brook	2 violations	Yes	8	D
91	Minooka	2 violations	Yes	6	A-
92	Sugar Grove	2 violations	Yes	7	A-
93	Salem	2 violations	Yes	7	C
94	Waterloo	2 violations	Yes	1	C
95	Steger	2 violations	Yes	8	B+
96	Lake Bluff	2 violations	Yes	18	C+
97	Wilmington	2 violations	Yes	10	C+
98	Monee	2 violations	Yes	2	B
99	Virden	2 violations	Yes	15	A-
100	Athens	2 violations	Yes	0	B+
101	Red Bud	2 violations	Yes	3	B-
102	South Jacksonville	2 violations	Yes	3	C-
103	Casey	2 violations	Yes	16	B
104	Diamond	2 violations	Yes	20	A-
105	Henry	2 violations	Yes	3	A-
106	Erie	2 violations	Yes	4	C+
107	Milford	2 violations	Yes	5	C+
108	Waterman	2 violations	Yes	17	A-
109	Oakwood	2 violations	Yes	18	A-
110	North Utica	2 violations	Yes	25	B
111	Griggsville	2 violations	Yes	0	A-
112	South Pekin	2 violations	Yes	0	B+
113	Long Grove	2 violations	Yes	51	C-
114	Pearl City	2 violations	Yes	0	D
115	Tonica	2 violations	Yes	16	A
116	Cordova	2 violations	Yes	2	B-
117	Creston	2 violations	Yes	0	A-
118	Williamsfield	2 violations	Yes	5	A-
119	Godley	2 violations	Yes	0	A-
120	Andover	2 violations	Yes	0	A-
121	West Union	2 violations	Yes	0	A-
122	London Mills	2 violations	Yes	1	A
123	Schaumburg	1 violations	Yes	17	B+
124	Des Plaines	1 violations	Yes	0	B+
125	Quincy	1 violations	Yes	3	B-
126	Rock Island	1 violations	Yes	5	B-
127	Moline	1 violations	Yes	7	C
128	Lombard	1 violations	Yes	1	A-
129	Crystal Lake	1 violations	Yes	4	A-
130	Saint Charles	1 violations	Yes	3	B+
131	Mattoon	1 violations	Yes	14	B-
132	Wilmette	1 violations	Yes	0	A
133	Lockport	1 violations	Yes	20	F
134	Belvidere	1 violations	Yes	8	A-
135	Zion	1 violations	Yes	1	B
136	South Elgin	1 violations	Yes	28	C
137	Jacksonville	1 violations	Yes	28	B-
138	Yorkville	1 violations	Yes	83	C+
139	Weston	1 violations	Yes	6	A
140	Canton	1 violations	Yes	7	B+
141	Glen Carbon	1 violations	Yes	0	B
142	Kewanee	1 violations	Yes	34	B
143	Plano	1 violations	Yes	0	B+
144	Winnetka	1 violations	Yes	0	A
145	Warrenville	1 violations	Yes	0	B+
146	Carlinville	1 violations	Yes	74	D
147	Highland	1 violations	Yes	16	B
148	La Salle	1 violations	Yes	6	B-
149	Harvard	1 violations	Yes	3	A
150	Crete	1 violations	Yes	4	B
151	Gilberts	1 violations	Yes	0	A-
152	West Dundee	1 violations	Yes	7	A
153	Rockton	1 violations	Yes	31	C
154	Clinton	1 violations	Yes	18	B+
155	Mount Carmel	1 violations	Yes	11	B
156	Elburn	1 violations	Yes	63	D
157	Litchfield	1 violations	Yes	5	D+
158	Dekalb	1 violations	Yes	2	A-
159	Milan	1 violations	Yes	28	D
160	Metropolis	1 violations	Yes	0	A-
161	Chillicothe	1 violations	Yes	11	D+
162	Winchester	1 violations	Yes	8	B-
163	Beardstown	1 violations	Yes	1	A
164	Coal City	1 violations	Yes	40	D
165	Wonder Lake	1 violations	Yes	6	C+
166	Staunton	1 violations	Yes	21	C+
167	Watseka	1 violations	Yes	9	A-
168	Genoa	1 violations	Yes	4	A
169	Fox River Grove	1 violations	Yes	10	B
170	Breese	1 violations	Yes	0	C+
171	Beecher	1 violations	Yes	0	A-
172	Morrison	1 violations	Yes	3	B+
173	Smithton	1 violations	Yes	7	B
174	Rochester	1 violations	Yes	0	A-
175	Gillespie	1 violations	Yes	14	C+
176	Le Roy	1 violations	Yes	12	D
177	Fulton	1 violations	Yes	6	B
178	Lakemoor	1 violations	Yes	0	B+
179	Marquette Heights	1 violations	Yes	0	A
180	Menard	1 violations	Yes	1	F
181	Tamms	1 violations	Yes	0	B+
182	Grayslake	1 violations	Yes	7	B+
183	Farmington	1 violations	Yes	24	A-
184	Prospect Heights	1 violations	Yes	9	B+
185	Nokomis	1 violations	Yes	7	A
186	Elwood	1 violations	Yes	2	A-
187	Groveland	1 violations	Yes	0	A+
188	Vienna	1 violations	Yes	17	B
189	Prophetstown	1 violations	Yes	2	B
190	Carrier Mills	1 violations	Yes	3	A-
191	Elmwood	1 violations	Yes	9	A
192	Port Byron	1 violations	Yes	4	B-
193	Lexington	1 violations	Yes	2	B+
194	Chenoa	1 violations	Yes	19	F
195	East Chicago Heights	1 violations	Yes	19	B-
196	Gilman	1 violations	Yes	1	B+
197	Atlanta	1 violations	Yes	8	B+
198	Neoga	1 violations	Yes	32	B+
199	Earlville	1 violations	Yes	0	A
200	Grayville	1 violations	Yes	0	A-
201	Warsaw	1 violations	Yes	12	A-
202	Kincaid	1 violations	Yes	4	B+
203	North Pekin	1 violations	Yes	1	A-
204	Oak Brook Terr	1 violations	Yes	7	B+
205	Murrayville	1 violations	Yes	0	B+
206	Payson	1 violations	Yes	3	A-
207	Danvers	1 violations	Yes	48	B-
208	New Berlin	1 violations	Yes	28	D
209	Tower Lakes	1 violations	Yes	1	B-
210	Ashland	1 violations	Yes	10	A-
211	Wyoming	1 violations	Yes	8	B+
212	Hanna City	1 violations	Yes	6	A
213	Downs	1 violations	Yes	8	B
214	Hillcrest	1 violations	Yes	4	B+
215	Martinsville	1 violations	Yes	3	B+
216	Nauvoo	1 violations	Yes	20	B+
217	Windsor	1 violations	Yes	11	C-
218	Waverly	1 violations	Yes	22	A
219	Toulon	1 violations	Yes	13	B
220	Loda	1 violations	Yes	1	B
221	Oquawka	1 violations	Yes	0	A+
222	Royalton	1 violations	Yes	0	B
223	Chebanse	1 violations	Yes	6	B+
224	Meredosia	1 violations	Yes	0	A-
225	Valrico	1 violations	Yes	0	A-
226	Washburn	1 violations	Yes	0	B+
227	Lovington	1 violations	Yes	1	B-
228	Hennepin	1 violations	Yes	7	A-
229	Raymond	1 violations	Yes	0	A+
230	Wataga	1 violations	Yes	3	B
231	Argenta	1 violations	Yes	0	B
232	Franklin Grove	1 violations	Yes	0	A-
233	Tallula	1 violations	Yes	0	A-
234	Alexis	1 violations	Yes	3	B+
235	Dallas City	1 violations	Yes	1	B+
236	Oakland	1 violations	Yes	0	B+
237	Vermont	1 violations	Yes	24	D
238	Ashkum	1 violations	Yes	11	C+
239	Taylor Ridge	1 violations	Yes	6	B+
240	Kirkwood	1 violations	Yes	27	B+
241	Mathersville	1 violations	Yes	0	A
242	Coffeen	1 violations	Yes	7	B
243	Deer Creek	1 violations	Yes	1	A-
244	Ashmore	1 violations	Yes	0	C
245	Ursa	1 violations	Yes	1	A
246	Keyesport	1 violations	Yes	9	A-
247	Nebo	1 violations	Yes	1	D
248	Blandinsville	1 violations	Yes	6	A
249	Grand Ridge	1 violations	Yes	26	B+
250	Tower Hill	1 violations	Yes	1	B+

FAQ

Frequently asked questions about nitrate in Illinois

Is nitrate in Illinois tap water dangerous?

Yes — 250 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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