Nitrate Contamination

Nitrate in Iowa Drinking Water

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

282

Cities Tested

282

Has Violations

100%

% Has Violations

5.0 violations

State Avg

▼ 0% vs national

vs National

297

Health Violations

Analysis

Nitrate in Iowa: what the data shows

Iowa has 282 cities with nitrate-related violations. The EPA MCL for nitrate is 10 mg/L (measured as nitrogen). The state has 282 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%

282 of 282 cities

← = Exactly at national rate

National avg

100%

7727 of 7727 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	George	19 violations	Yes	19	A-
17	Shellsburg	19 violations	Yes	12	A-
18	Earlville	19 violations	Yes	15	A-
19	Rock Rapids	18 violations	Yes	12	B+
20	Keystone	17 violations	Yes	7	A-
21	Winterset	16 violations	Yes	20	A-
22	Panora	16 violations	Yes	26	A-
23	Marengo	16 violations	Yes	12	B-
24	Sioux Rapids	16 violations	Yes	13	B+
25	Battle Creek	14 violations	Yes	13	A-
26	Waverly	13 violations	Yes	2	B+
27	Rock Valley	13 violations	Yes	13	B+
28	Jesup	13 violations	Yes	0	A
29	Atkins	13 violations	Yes	6	A-
30	Mapleton	13 violations	Yes	12	A
31	Clarinda	12 violations	Yes	48	B
32	Dyersville	12 violations	Yes	23	A
33	Solon	12 violations	Yes	157	F
34	Peosta	12 violations	Yes	7	A-
35	North Liberty	11 violations	Yes	29	B-
36	Holstein	11 violations	Yes	7	A-
37	Marion	10 violations	Yes	6	A-
38	Algona	10 violations	Yes	14	B
39	Rockwell City	10 violations	Yes	6	B+
40	Wapello	10 violations	Yes	12	B+
41	Delhi	10 violations	Yes	0	B+
42	Davenport	9 violations	Yes	2	C-
43	Ames	9 violations	Yes	15	B+
44	Cherokee	9 violations	Yes	2	A-
45	Princeton	9 violations	Yes	18	B
46	Coralville	8 violations	Yes	15	B
47	Williamsburg	8 violations	Yes	3	A-
48	Missouri Valley	7 violations	Yes	6	C+
49	Lake City	7 violations	Yes	0	A
50	Janesville	7 violations	Yes	5	A
51	Newhall	7 violations	Yes	2	A-
52	Wall Lake	7 violations	Yes	4	A-
53	Schaller	7 violations	Yes	8	A
54	Ankeny	6 violations	Yes	15	B
55	Marshalltown	6 violations	Yes	4	A-
56	Boone	6 violations	Yes	9	B
57	Lisbon	6 violations	Yes	21	B+
58	Oxford	6 violations	Yes	24	C+
59	Griswold	6 violations	Yes	2	A-
60	Wheatland	6 violations	Yes	5	A-
61	Merrill	6 violations	Yes	4	A
62	Gilman	6 violations	Yes	7	A+
63	Eldridge	5 violations	Yes	9	B+
64	Hiawatha	5 violations	Yes	12	B-
65	Hospers	5 violations	Yes	5	B+
66	Belle Plaine	5 violations	Yes	2	B+
67	Kingsley	5 violations	Yes	3	A-
68	Buffalo	5 violations	Yes	12	A-
69	Saint Ansgar	5 violations	Yes	2	A
70	Riverside	5 violations	Yes	6	A-
71	Malvern	5 violations	Yes	2	B+
72	Dunkerton	5 violations	Yes	6	A-
73	Shelby	5 violations	Yes	3	A-
74	Alburnett	5 violations	Yes	3	A
75	Minden	5 violations	Yes	3	A-
76	Des Moines	4 violations	Yes	7	B+
77	Waterloo	4 violations	Yes	3	A-
78	Council Bluffs	4 violations	Yes	8	B+
79	Grimes	4 violations	Yes	13	A-
80	Maquoketa	4 violations	Yes	18	A-
81	Red Oak	4 violations	Yes	9	A-
82	Manning	4 violations	Yes	4	A-
83	Forest City	4 violations	Yes	8	B
84	Woodward	4 violations	Yes	17	B
85	Prairie City	4 violations	Yes	3	A
86	Akron	4 violations	Yes	4	A-
87	Slater	4 violations	Yes	2	B+
88	Strawberry Point	4 violations	Yes	1	A
89	Lake View	4 violations	Yes	1	A
90	Van Meter	4 violations	Yes	6	A-
91	Inwood	4 violations	Yes	2	A
92	Keota	4 violations	Yes	4	A
93	Elkhart	4 violations	Yes	0	A-
94	Gilbertville	4 violations	Yes	0	A-
95	Dayton	4 violations	Yes	7	A
96	Fonda	4 violations	Yes	1	B+
97	Brighton	4 violations	Yes	0	A
98	Elma	4 violations	Yes	0	A
99	Altoona	3 violations	Yes	20	B+
100	Bondurant	3 violations	Yes	1	A
101	Washington	3 violations	Yes	13	B+
102	Camanche	3 violations	Yes	0	A
103	Carlisle	3 violations	Yes	0	A-
104	Fairfax	3 violations	Yes	2	A-
105	Kalona	3 violations	Yes	3	B+
106	West Union	3 violations	Yes	3	A
107	Lamoni	3 violations	Yes	5	B+
108	Corning	3 violations	Yes	2	A-
109	Granger	3 violations	Yes	1	A-
110	Traer	3 violations	Yes	0	A
111	Bedford	3 violations	Yes	19	A-
112	Gilbert	3 violations	Yes	1	B+
113	Sheffield	3 violations	Yes	2	A-
114	Aplington	3 violations	Yes	1	A-
115	Conrad	3 violations	Yes	1	A
116	Dunlap	3 violations	Yes	3	A-
117	Paullina	3 violations	Yes	3	A
118	Fredericksburg	3 violations	Yes	0	A
119	Neola	3 violations	Yes	8	B+
120	Donnellson	3 violations	Yes	20	B+
121	Armstrong	3 violations	Yes	1	B+
122	Okoboji	3 violations	Yes	1	A
123	Blairstown	3 violations	Yes	3	A-
124	Montrose	3 violations	Yes	1	A
125	Coggon	3 violations	Yes	0	A-
126	Pomeroy	3 violations	Yes	1	A-
127	Olin	3 violations	Yes	2	A
128	Sutherland	3 violations	Yes	3	A-
129	Badger	3 violations	Yes	6	A
130	Anthon	3 violations	Yes	0	A
131	Charter Oak	3 violations	Yes	3	A
132	Ottumwa	2 violations	Yes	6	B+
133	Cedar Falls	2 violations	Yes	4	A-
134	Creston	2 violations	Yes	9	A-
135	Mason City	2 violations	Yes	18	A-
136	Burlington	2 violations	Yes	7	B+
137	Johnston	2 violations	Yes	6	B+
138	Storm Lake	2 violations	Yes	1	A-
139	Fort Madison	2 violations	Yes	6	A
140	Denison	2 violations	Yes	0	A
141	Mount Pleasant	2 violations	Yes	2	A
142	Decorah	2 violations	Yes	11	B+
143	Sioux Center	2 violations	Yes	0	A-
144	Perry	2 violations	Yes	3	A
145	Independence	2 violations	Yes	4	A
146	Oelwein	2 violations	Yes	2	A
147	Avoca	2 violations	Yes	6	A
148	Anamosa	2 violations	Yes	5	B-
149	Manchester	2 violations	Yes	1	A
150	Shenandoah	2 violations	Yes	2	A
151	Story City	2 violations	Yes	0	A
152	Hawarden	2 violations	Yes	4	A
153	Center Point	2 violations	Yes	3	B
154	Mitchellville	2 violations	Yes	1	A
155	South Amana	2 violations	Yes	1	A-
156	Ely	2 violations	Yes	0	A
157	Colfax	2 violations	Yes	2	A-
158	Lake Mills	2 violations	Yes	3	A
159	Ida Grove	2 violations	Yes	2	A-
160	Sumner	2 violations	Yes	0	A+
161	Epworth	2 violations	Yes	0	A
162	Durant	2 violations	Yes	2	A
163	Columbus Junction	2 violations	Yes	0	A-
164	Remsen	2 violations	Yes	2	A-
165	Reinbeck	2 violations	Yes	1	B+
166	Woodbine	2 violations	Yes	3	B+
167	Ackley	2 violations	Yes	1	A-
168	Palo	2 violations	Yes	4	A
169	Dike	2 violations	Yes	2	A
170	Clarksville	2 violations	Yes	1	A
171	Middle Amana	2 violations	Yes	1	B+
172	Jewell	2 violations	Yes	0	B
173	Glidden	2 violations	Yes	0	A-
174	Fairbank	2 violations	Yes	7	A
175	Sidney	2 violations	Yes	1	B
176	North English	2 violations	Yes	0	A
177	Treynor	2 violations	Yes	0	A-
178	Mechanicsville	2 violations	Yes	0	A-
179	Tabor	2 violations	Yes	0	A-
180	Larchwood	2 violations	Yes	1	A
181	Primghar	2 violations	Yes	0	A-
182	Hamburg	2 violations	Yes	0	A
183	Victor	2 violations	Yes	1	C+
184	Cambridge	2 violations	Yes	1	A-
185	Correctionville	2 violations	Yes	1	A
186	Morning Sun	2 violations	Yes	1	A
187	Mcgregor	2 violations	Yes	6	B+
188	Elgin	2 violations	Yes	0	A-
189	Hopkinton	2 violations	Yes	0	A
190	Clermont	2 violations	Yes	4	B+
191	Richland	2 violations	Yes	5	A
192	Zearing	2 violations	Yes	2	A-
193	Whittemore	2 violations	Yes	0	A-
194	Breda	2 violations	Yes	0	A
195	Sioux City	1 violations	Yes	14	B
196	Centerville	1 violations	Yes	4	B+
197	Waukee	1 violations	Yes	13	A-
198	Oskaloosa	1 violations	Yes	11	A-
199	Knoxville	1 violations	Yes	2	B
200	Fairfield	1 violations	Yes	15	A-
201	Keokuk	1 violations	Yes	0	A-
202	Tama	1 violations	Yes	1	A-
203	Clear Lake	1 violations	Yes	2	A-
204	May City	1 violations	Yes	0	A-
205	Ireton	1 violations	Yes	4	A-
206	Osceola	1 violations	Yes	21	B
207	Luther	1 violations	Yes	8	A
208	Evansdale	1 violations	Yes	0	A+
209	Hampton	1 violations	Yes	10	A-
210	West Burlington	1 violations	Yes	17	B+
211	Chariton	1 violations	Yes	64	B-
212	Huxley	1 violations	Yes	1	A
213	Jefferson	1 violations	Yes	2	A
214	West Liberty	1 violations	Yes	6	A
215	Carter Lake	1 violations	Yes	6	A-
216	Osage	1 violations	Yes	9	B+
217	Milford	1 violations	Yes	0	A
218	Montezuma	1 violations	Yes	0	A-
219	Wilton	1 violations	Yes	0	A-
220	Onawa	1 violations	Yes	0	A-
221	Sibley	1 violations	Yes	0	A-
222	Bloomfield	1 violations	Yes	41	A-
223	Postville	1 violations	Yes	0	A-
224	West Branch	1 violations	Yes	0	B
225	Belmond	1 violations	Yes	0	A
226	Ogden	1 violations	Yes	3	A-
227	Toledo	1 violations	Yes	8	A
228	Cascade	1 violations	Yes	0	A
229	Bellevue	1 violations	Yes	18	A-
230	Northwood	1 violations	Yes	3	A
231	Audubon	1 violations	Yes	2	A
232	Pocahontas	1 violations	Yes	5	A
233	Leon	1 violations	Yes	20	A-
234	Stuart	1 violations	Yes	17	A
235	Mount Ayr	1 violations	Yes	10	A
236	Corydon	1 violations	Yes	0	A-
237	Guthrie Center	1 violations	Yes	1	A-
238	Nashua	1 violations	Yes	0	A-
239	Walcott	1 violations	Yes	0	A
240	Logan	1 violations	Yes	0	A
241	Roland	1 violations	Yes	4	A
242	Sanborn	1 violations	Yes	0	A
243	New Sharon	1 violations	Yes	0	A
244	Laurens	1 violations	Yes	0	A
245	Central City	1 violations	Yes	3	A
246	Springville	1 violations	Yes	0	A
247	Alton	1 violations	Yes	1	A
248	Elkader	1 violations	Yes	0	B+
249	Melcher-Dallas	1 violations	Yes	3	A
250	Marcus	1 violations	Yes	10	A
251	Rockwell	1 violations	Yes	4	A
252	Clarence	1 violations	Yes	3	A
253	Winfield	1 violations	Yes	0	A
254	Baxter	1 violations	Yes	0	A-
255	Preston	1 violations	Yes	1	A
256	Lawton	1 violations	Yes	3	A
257	Eldon	1 violations	Yes	10	A-
258	Le Grand	1 violations	Yes	2	A
259	Newell	1 violations	Yes	0	A
260	Graettinger	1 violations	Yes	4	A
261	Sully	1 violations	Yes	8	A
262	Buffalo Center	1 violations	Yes	0	A
263	Winthrop	1 violations	Yes	0	A
264	Long Grove	1 violations	Yes	6	A
265	Riceville	1 violations	Yes	0	A
266	Gladbrook	1 violations	Yes	1	A
267	Milo	1 violations	Yes	4	A
268	Dakota City	1 violations	Yes	0	A
269	Garnavillo	1 violations	Yes	0	A
270	Whiting	1 violations	Yes	0	A
271	Grand Junction	1 violations	Yes	2	A
272	Wellsburg	1 violations	Yes	16	A
273	Stratford	1 violations	Yes	6	A-
274	Albert City	1 violations	Yes	0	A
275	Kellogg	1 violations	Yes	1	A
276	Grand Mound	1 violations	Yes	0	A
277	Radcliffe	1 violations	Yes	3	A
278	Wyoming	1 violations	Yes	0	A
279	Ellsworth	1 violations	Yes	9	A-
280	Titonka	1 violations	Yes	0	A-
281	Rolfe	1 violations	Yes	0	A+
282	Scranton	1 violations	Yes	6	B

FAQ

Frequently asked questions about nitrate in Iowa

Is nitrate in Iowa tap water dangerous?

Yes — 282 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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