Nitrate Contamination

Nitrate in Iowa Drinking Water

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

286

Cities Tested

286

Has Violations

100%

% Has Violations

5.2 violations

State Avg

▼ 0% vs national

vs National

303

Health Violations

Analysis

Nitrate in Iowa: what the data shows

Iowa has 286 cities with nitrate-related violations. The EPA MCL for nitrate is 10 mg/L (measured as nitrogen). The state has 286 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

Iowa

100%

286 of 286 cities

← = Exactly at national rate

National avg

100%

8001 of 8001 cities

City Map

Nitrate data across Iowa

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 Iowa

Highest Nitrate levels (violations)

All Cities

All Iowa cities ranked by nitrate level

#	City	Level	Violations?	Violations	Grade
1	Monticello	70 violations	Yes	22	D
2	Blue Grass	39 violations	Yes	43	C
3	Doon	35 violations	Yes	32	B+
4	Iowa City	33 violations	Yes	171	F
5	Muscatine	32 violations	Yes	46	F
6	Everly	30 violations	Yes	26	A-
7	Dubuque	28 violations	Yes	30	F
8	Moville	27 violations	Yes	11	A-
9	Early	26 violations	Yes	23	B+
10	Cedar Rapids	24 violations	Yes	31	D
11	Wellman	24 violations	Yes	24	A-
12	Essex	22 violations	Yes	15	A-
13	Fort Dodge	21 violations	Yes	19	D+
14	Schleswig	20 violations	Yes	14	A
15	Farmington	20 violations	Yes	20	A
16	Shellsburg	19 violations	Yes	12	A-
17	George	19 violations	Yes	19	A-
18	Earlville	19 violations	Yes	15	A-
19	Rock Rapids	18 violations	Yes	12	B+
20	De Witt	18 violations	Yes	26	B+
21	Keystone	17 violations	Yes	7	A-
22	Winterset	16 violations	Yes	20	A-
23	Panora	16 violations	Yes	26	A-
24	Marengo	16 violations	Yes	12	B-
25	Sioux Rapids	16 violations	Yes	13	B+
26	Battle Creek	14 violations	Yes	13	A-
27	Waverly	13 violations	Yes	2	B+
28	Rock Valley	13 violations	Yes	13	B+
29	Jesup	13 violations	Yes	0	A
30	Atkins	13 violations	Yes	6	A-
31	Mapleton	13 violations	Yes	12	A
32	Clarinda	12 violations	Yes	48	B
33	Dyersville	12 violations	Yes	23	A
34	Solon	12 violations	Yes	157	F
35	Peosta	12 violations	Yes	7	A-
36	Bettendorf	12 violations	Yes	11	C+
37	North Liberty	11 violations	Yes	29	B-
38	Holstein	11 violations	Yes	7	A-
39	Walford	11 violations	Yes	7	D
40	Marion	10 violations	Yes	6	A-
41	Algona	10 violations	Yes	14	B
42	Rockwell City	10 violations	Yes	6	B+
43	Wapello	10 violations	Yes	12	B+
44	Swisher	10 violations	Yes	37	F
45	Delhi	10 violations	Yes	0	B+
46	Davenport	9 violations	Yes	2	C-
47	Ames	9 violations	Yes	15	B+
48	Cherokee	9 violations	Yes	2	A-
49	Princeton	9 violations	Yes	18	B
50	Coralville	8 violations	Yes	15	B
51	Williamsburg	8 violations	Yes	3	A-
52	Missouri Valley	7 violations	Yes	6	C+
53	Wall Lake	7 violations	Yes	4	A-
54	Lake City	7 violations	Yes	0	A
55	Janesville	7 violations	Yes	5	A
56	Newhall	7 violations	Yes	2	A-
57	Schaller	7 violations	Yes	8	A
58	Ankeny	6 violations	Yes	15	B
59	Marshalltown	6 violations	Yes	4	A-
60	Boone	6 violations	Yes	9	B
61	Lisbon	6 violations	Yes	21	B+
62	Oxford	6 violations	Yes	24	C+
63	Griswold	6 violations	Yes	2	A-
64	Wheatland	6 violations	Yes	5	A-
65	Merrill	6 violations	Yes	4	A
66	Gilman	6 violations	Yes	7	A+
67	Eldridge	5 violations	Yes	9	B+
68	Hiawatha	5 violations	Yes	12	B-
69	Hospers	5 violations	Yes	5	B+
70	Belle Plaine	5 violations	Yes	2	B+
71	Buffalo	5 violations	Yes	12	A-
72	Kingsley	5 violations	Yes	3	A-
73	Riverside	5 violations	Yes	6	A-
74	Saint Ansgar	5 violations	Yes	2	A
75	Dunkerton	5 violations	Yes	6	A-
76	Malvern	5 violations	Yes	2	B+
77	Shelby	5 violations	Yes	3	A-
78	Alburnett	5 violations	Yes	3	A
79	Minden	5 violations	Yes	3	A-
80	Des Moines	4 violations	Yes	7	B+
81	Waterloo	4 violations	Yes	3	A-
82	Council Bluffs	4 violations	Yes	8	B+
83	Grimes	4 violations	Yes	13	A-
84	Red Oak	4 violations	Yes	9	A-
85	Maquoketa	4 violations	Yes	18	A-
86	Woodward	4 violations	Yes	17	B
87	Manning	4 violations	Yes	4	A-
88	Forest City	4 violations	Yes	8	B
89	Prairie City	4 violations	Yes	3	A
90	Slater	4 violations	Yes	2	B+
91	Akron	4 violations	Yes	4	A-
92	Van Meter	4 violations	Yes	6	A-
93	Strawberry Point	4 violations	Yes	1	A
94	Lake View	4 violations	Yes	1	A
95	Inwood	4 violations	Yes	2	A
96	Keota	4 violations	Yes	4	A
97	Elkhart	4 violations	Yes	0	A-
98	Gilbertville	4 violations	Yes	0	A-
99	Dayton	4 violations	Yes	7	A
100	Fonda	4 violations	Yes	1	B+
101	Brighton	4 violations	Yes	0	A
102	Elma	4 violations	Yes	0	A
103	Altoona	3 violations	Yes	20	B+
104	Bondurant	3 violations	Yes	1	A
105	Washington	3 violations	Yes	13	B+
106	Camanche	3 violations	Yes	0	A
107	Carlisle	3 violations	Yes	0	A-
108	Fairfax	3 violations	Yes	2	A-
109	Kalona	3 violations	Yes	3	B+
110	Sutherland	3 violations	Yes	3	A-
111	West Union	3 violations	Yes	3	A
112	Lamoni	3 violations	Yes	5	B+
113	Corning	3 violations	Yes	2	A-
114	Granger	3 violations	Yes	1	A-
115	Traer	3 violations	Yes	0	A
116	Bedford	3 violations	Yes	19	A-
117	Gilbert	3 violations	Yes	1	B+
118	Sheffield	3 violations	Yes	2	A-
119	Aplington	3 violations	Yes	1	A-
120	Conrad	3 violations	Yes	1	A
121	Dunlap	3 violations	Yes	3	A-
122	Paullina	3 violations	Yes	3	A
123	Fredericksburg	3 violations	Yes	0	A
124	Armstrong	3 violations	Yes	1	B+
125	Neola	3 violations	Yes	8	B+
126	Donnellson	3 violations	Yes	20	B+
127	Okoboji	3 violations	Yes	1	A
128	Blairstown	3 violations	Yes	3	A-
129	Montrose	3 violations	Yes	1	A
130	Coggon	3 violations	Yes	0	A-
131	Pomeroy	3 violations	Yes	1	A-
132	Olin	3 violations	Yes	2	A
133	Badger	3 violations	Yes	6	A
134	Anthon	3 violations	Yes	0	A
135	Charter Oak	3 violations	Yes	3	A
136	Ottumwa	2 violations	Yes	6	B+
137	Cedar Falls	2 violations	Yes	4	A-
138	Burlington	2 violations	Yes	7	B+
139	Creston	2 violations	Yes	9	A-
140	Mason City	2 violations	Yes	18	A-
141	Johnston	2 violations	Yes	6	B+
142	Fort Madison	2 violations	Yes	6	A-
143	Denison	2 violations	Yes	0	A
144	Storm Lake	2 violations	Yes	1	A-
145	Mount Pleasant	2 violations	Yes	2	A
146	Decorah	2 violations	Yes	11	B+
147	Sioux Center	2 violations	Yes	0	A-
148	Perry	2 violations	Yes	3	A
149	Independence	2 violations	Yes	4	A
150	Oelwein	2 violations	Yes	2	A
151	Avoca	2 violations	Yes	6	A
152	Anamosa	2 violations	Yes	5	B-
153	Manchester	2 violations	Yes	1	A
154	Shenandoah	2 violations	Yes	2	A
155	Story City	2 violations	Yes	0	A
156	South Amana	2 violations	Yes	1	A-
157	Center Point	2 violations	Yes	3	B
158	Hawarden	2 violations	Yes	4	A
159	Mitchellville	2 violations	Yes	1	A
160	Ely	2 violations	Yes	0	A
161	Colfax	2 violations	Yes	2	A-
162	Lake Mills	2 violations	Yes	3	A
163	Ida Grove	2 violations	Yes	2	A-
164	Sumner	2 violations	Yes	0	A+
165	Epworth	2 violations	Yes	0	A
166	Durant	2 violations	Yes	2	A
167	Columbus Junction	2 violations	Yes	0	A-
168	Remsen	2 violations	Yes	2	A-
169	Reinbeck	2 violations	Yes	1	B+
170	Woodbine	2 violations	Yes	3	B+
171	Ackley	2 violations	Yes	1	A-
172	Palo	2 violations	Yes	4	A
173	Dike	2 violations	Yes	2	A
174	Clarksville	2 violations	Yes	1	A
175	Middle Amana	2 violations	Yes	1	B+
176	Jewell	2 violations	Yes	0	B
177	Glidden	2 violations	Yes	0	A-
178	Fairbank	2 violations	Yes	7	A
179	Sidney	2 violations	Yes	1	B
180	North English	2 violations	Yes	0	A
181	Treynor	2 violations	Yes	0	A-
182	Mechanicsville	2 violations	Yes	0	A-
183	Tabor	2 violations	Yes	0	A-
184	Larchwood	2 violations	Yes	1	A
185	Mcgregor	2 violations	Yes	6	B+
186	Primghar	2 violations	Yes	0	A-
187	Hamburg	2 violations	Yes	0	A
188	Victor	2 violations	Yes	1	C+
189	Cambridge	2 violations	Yes	1	A-
190	Correctionville	2 violations	Yes	1	A
191	Morning Sun	2 violations	Yes	1	A
192	Elgin	2 violations	Yes	0	A-
193	Hopkinton	2 violations	Yes	0	A
194	Clermont	2 violations	Yes	4	B+
195	Richland	2 violations	Yes	5	A
196	Zearing	2 violations	Yes	2	A-
197	Whittemore	2 violations	Yes	0	A-
198	Breda	2 violations	Yes	0	A
199	Sioux City	1 violations	Yes	14	B
200	Centerville	1 violations	Yes	4	B+
201	Waukee	1 violations	Yes	13	A-
202	Oskaloosa	1 violations	Yes	11	A-
203	Knoxville	1 violations	Yes	2	B
204	Fairfield	1 violations	Yes	15	A-
205	Keokuk	1 violations	Yes	0	A-
206	Osceola	1 violations	Yes	21	B
207	Graettinger	1 violations	Yes	4	A
208	Tama	1 violations	Yes	1	A-
209	Clear Lake	1 violations	Yes	2	A-
210	May City	1 violations	Yes	0	A-
211	Stratford	1 violations	Yes	6	A-
212	Ireton	1 violations	Yes	4	A-
213	Luther	1 violations	Yes	8	A
214	Carter Lake	1 violations	Yes	6	A-
215	Evansdale	1 violations	Yes	0	A+
216	Huxley	1 violations	Yes	1	A
217	Hampton	1 violations	Yes	10	A-
218	West Burlington	1 violations	Yes	17	B+
219	Chariton	1 violations	Yes	64	B-
220	Jefferson	1 violations	Yes	2	A
221	West Liberty	1 violations	Yes	6	A
222	Osage	1 violations	Yes	9	B+
223	Milford	1 violations	Yes	0	A
224	Montezuma	1 violations	Yes	0	A-
225	Wilton	1 violations	Yes	0	A-
226	West Branch	1 violations	Yes	0	B
227	Onawa	1 violations	Yes	0	A-
228	Sibley	1 violations	Yes	0	A-
229	Bellevue	1 violations	Yes	18	A-
230	Bloomfield	1 violations	Yes	41	A-
231	Postville	1 violations	Yes	0	A-
232	Belmond	1 violations	Yes	0	A
233	Ogden	1 violations	Yes	3	A-
234	Toledo	1 violations	Yes	8	A
235	Cascade	1 violations	Yes	0	A
236	Northwood	1 violations	Yes	3	A
237	Audubon	1 violations	Yes	2	A
238	Pocahontas	1 violations	Yes	5	A
239	Leon	1 violations	Yes	20	A-
240	Stuart	1 violations	Yes	17	A
241	Mount Ayr	1 violations	Yes	10	A
242	Corydon	1 violations	Yes	0	A-
243	Guthrie Center	1 violations	Yes	1	A-
244	Nashua	1 violations	Yes	0	A-
245	Walcott	1 violations	Yes	0	A
246	Logan	1 violations	Yes	0	A
247	Roland	1 violations	Yes	4	A
248	Sanborn	1 violations	Yes	0	A
249	New Sharon	1 violations	Yes	0	A
250	Laurens	1 violations	Yes	0	A
251	Central City	1 violations	Yes	3	A
252	Springville	1 violations	Yes	0	A
253	Alton	1 violations	Yes	1	A
254	Elkader	1 violations	Yes	0	B+
255	Melcher-Dallas	1 violations	Yes	3	A
256	Marcus	1 violations	Yes	10	A
257	Rockwell	1 violations	Yes	4	A
258	Clarence	1 violations	Yes	3	A
259	Winfield	1 violations	Yes	0	A
260	Baxter	1 violations	Yes	0	A-
261	Long Grove	1 violations	Yes	6	A
262	Preston	1 violations	Yes	1	A
263	Lawton	1 violations	Yes	3	A
264	Eldon	1 violations	Yes	10	A-
265	Le Grand	1 violations	Yes	2	A
266	Newell	1 violations	Yes	0	A
267	Sully	1 violations	Yes	8	A
268	Buffalo Center	1 violations	Yes	0	A
269	Winthrop	1 violations	Yes	0	A
270	Riceville	1 violations	Yes	0	A
271	Gladbrook	1 violations	Yes	1	A
272	Milo	1 violations	Yes	4	A
273	Dakota City	1 violations	Yes	0	A
274	Garnavillo	1 violations	Yes	0	A
275	Whiting	1 violations	Yes	0	A
276	Grand Junction	1 violations	Yes	2	A
277	Wellsburg	1 violations	Yes	16	A
278	Albert City	1 violations	Yes	0	A
279	Kellogg	1 violations	Yes	1	A
280	Grand Mound	1 violations	Yes	0	A
281	Radcliffe	1 violations	Yes	3	A
282	Wyoming	1 violations	Yes	0	A
283	Ellsworth	1 violations	Yes	9	A-
284	Titonka	1 violations	Yes	0	A-
285	Rolfe	1 violations	Yes	0	A+
286	Scranton	1 violations	Yes	6	B

FAQ

Frequently asked questions about nitrate in Iowa

Is nitrate in Iowa tap water dangerous?

Yes — 286 cities in Iowa 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 Iowa 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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