Nitrate Contamination

Nitrate in Ohio Drinking Water

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

311

Cities Tested

311

Has Violations

100%

% Has Violations

3.3 violations

State Avg

▼ 0% vs national

vs National

398

Health Violations

Analysis

Nitrate in Ohio: what the data shows

Ohio has 311 cities with nitrate-related violations. The EPA MCL for nitrate is 10 mg/L (measured as nitrogen). The state has 311 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

Ohio

100%

311 of 311 cities

← = Exactly at national rate

National avg

100%

8001 of 8001 cities

City Map

Nitrate data across Ohio

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 Ohio

Highest Nitrate levels (violations)

All Cities

All Ohio cities ranked by nitrate level

#	City	Level	Violations?	Violations	Grade
1	Columbus	23 violations	Yes	56	F
2	Kent	22 violations	Yes	36	F
3	Mansfield	21 violations	Yes	37	F
4	Fremont	20 violations	Yes	44	B-
5	Urbana	20 violations	Yes	24	C+
6	Akron	20 violations	Yes	36	D
7	Springfield	17 violations	Yes	42	F
8	Chardon	17 violations	Yes	25	F
9	Chesterland	17 violations	Yes	11	C-
10	Dayton	16 violations	Yes	43	F
11	Wooster	15 violations	Yes	14	F
12	Lebanon	14 violations	Yes	28	D
13	Waynesville	14 violations	Yes	25	D
14	Cincinnati	12 violations	Yes	10	F
15	Warren	12 violations	Yes	62	F
16	Defiance	12 violations	Yes	171	F
17	Fostoria	12 violations	Yes	32	F
18	Warsaw	12 violations	Yes	36	D+
19	Minerva	11 violations	Yes	5	B+
20	Bradford	11 violations	Yes	28	C
21	Stow	10 violations	Yes	4	C+
22	Piketon	10 violations	Yes	8	C
23	Massillon	9 violations	Yes	13	D+
24	Lima	8 violations	Yes	16	F
25	Napoleon	8 violations	Yes	20	A-
26	Garrettsville	8 violations	Yes	2	B-
27	Mentor	7 violations	Yes	6	B-
28	Bowling Green	7 violations	Yes	85	F
29	Maumee	7 violations	Yes	6	B-
30	West Milton	7 violations	Yes	54	B+
31	New Waterford	7 violations	Yes	11	C
32	Grand Rapids	7 violations	Yes	41	C
33	Laurelville	7 violations	Yes	4	B+
34	North Hampton	7 violations	Yes	0	B
35	Zanesville	6 violations	Yes	7	D+
36	Ravenna	6 violations	Yes	3	C
37	Jackson	6 violations	Yes	11	B-
38	Salem	6 violations	Yes	11	C+
39	Williamsport	6 violations	Yes	31	C-
40	Logan	6 violations	Yes	30	F
41	New Knoxville	6 violations	Yes	2	B-
42	Marietta	5 violations	Yes	11	F
43	Port Clinton	5 violations	Yes	46	D+
44	Tipp City	5 violations	Yes	0	C+
45	Bexley	5 violations	Yes	16	C
46	Wapakoneta	5 violations	Yes	7	B
47	Chagrin Falls	5 violations	Yes	1	C
48	Sardinia	5 violations	Yes	19	B-
49	Versailles	5 violations	Yes	4	B+
50	Seville	5 violations	Yes	3	B
51	Creston	5 violations	Yes	2	B
52	West Farmington	5 violations	Yes	22	C-
53	Thornville	5 violations	Yes	0	B+
54	Lockbourne	5 violations	Yes	2	B
55	Van Wert	4 violations	Yes	47	C
56	Hudson	4 violations	Yes	1	B-
57	Nelsonville	4 violations	Yes	23	D
58	Mount Orab	4 violations	Yes	2	A-
59	White Cottage	4 violations	Yes	47	F
60	Newton Falls	4 violations	Yes	6	C
61	Fayetteville	4 violations	Yes	19	C+
62	Lowell	4 violations	Yes	6	B+
63	New Paris	4 violations	Yes	39	D+
64	Enon	4 violations	Yes	0	A-
65	Glendale	4 violations	Yes	0	A-
66	Brilliant	4 violations	Yes	3	B-
67	South Amherst	4 violations	Yes	15	B+
68	Lynchburg	4 violations	Yes	5	A
69	Botkins	4 violations	Yes	10	B
70	Mogadore	4 violations	Yes	9	B
71	Rockford	4 violations	Yes	4	B-
72	Bloomingburg	4 violations	Yes	5	A-
73	Milford Center	4 violations	Yes	1	A-
74	Canton	3 violations	Yes	2	B-
75	Medina	3 violations	Yes	15	C+
76	Trenton	3 violations	Yes	10	B-
77	Lancaster	3 violations	Yes	6	B+
78	Athens	3 violations	Yes	4	B+
79	Newark	3 violations	Yes	6	B-
80	Ironton	3 violations	Yes	12	C-
81	Westerville	3 violations	Yes	18	C+
82	Circleville	3 violations	Yes	5	B
83	Piqua	3 violations	Yes	12	B
84	East Liverpool	3 violations	Yes	14	B
85	Oak Hill	3 violations	Yes	9	B-
86	Galion	3 violations	Yes	18	B-
87	Dennison	3 violations	Yes	13	A-
88	Bolivar	3 violations	Yes	11	C+
89	Delphos	3 violations	Yes	17	D+
90	Andover	3 violations	Yes	0	B-
91	Columbiana	3 violations	Yes	2	B
92	Bluffton	3 violations	Yes	19	B+
93	Mingo Junction	3 violations	Yes	3	B-
94	Paulding	3 violations	Yes	41	C+
95	Groveport	3 violations	Yes	1	A-
96	Middlefield	3 violations	Yes	14	B+
97	London	3 violations	Yes	10	B
98	Fredericktown	3 violations	Yes	0	B+
99	St Henry	3 violations	Yes	0	A-
100	Lakeville	3 violations	Yes	4	B-
101	Sugarcreek	3 violations	Yes	7	C+
102	Edgerton	3 violations	Yes	0	B+
103	Anna	3 violations	Yes	24	B
104	Orwell	3 violations	Yes	1	A-
105	Somerset	3 violations	Yes	18	B+
106	Chauncey	3 violations	Yes	0	B+
107	West Alexandria	3 violations	Yes	4	B
108	Malvern	3 violations	Yes	9	C-
109	Waynesburg	3 violations	Yes	2	B
110	Junction City	3 violations	Yes	0	A-
111	Arcadia	3 violations	Yes	23	C+
112	Washingtonville	3 violations	Yes	10	B
113	Spencer	3 violations	Yes	0	A-
114	Ohio City	3 violations	Yes	0	A-
115	Shiloh	3 violations	Yes	8	A-
116	Spring Valley	3 violations	Yes	0	A-
117	Kettering	2 violations	Yes	14	C
118	Delaware	2 violations	Yes	5	B
119	Barnesville	2 violations	Yes	14	C
120	Ripley	2 violations	Yes	1	A-
121	Vandalia	2 violations	Yes	10	B+
122	New Richmond	2 violations	Yes	0	B-
123	Sandusky	2 violations	Yes	6	A-
124	N Canton	2 violations	Yes	0	A-
125	Baltimore	2 violations	Yes	1	B
126	Franklin	2 violations	Yes	2	B+
127	Monroe	2 violations	Yes	2	B
128	Camden	2 violations	Yes	1	B+
129	Coshocton	2 violations	Yes	13	B+
130	Vermilion	2 violations	Yes	7	B+
131	Wellsville	2 violations	Yes	3	C+
132	Shelby	2 violations	Yes	19	B+
133	Bryan	2 violations	Yes	1	B+
134	New Lexington	2 violations	Yes	29	F
135	Bellevue	2 violations	Yes	5	B
136	Troy	2 violations	Yes	3	C
137	Union	2 violations	Yes	2	B+
138	Belpre	2 violations	Yes	4	B
139	Brookville	2 violations	Yes	2	B-
140	Sebring	2 violations	Yes	51	B-
141	Germantown	2 violations	Yes	21	B+
142	Waterford	2 violations	Yes	5	C+
143	Canal Fulton	2 violations	Yes	4	B
144	Ada	2 violations	Yes	2	B-
145	Byesville	2 violations	Yes	79	D
146	Coldwater	2 violations	Yes	1	A-
147	Millersburg	2 violations	Yes	4	B+
148	Newcomerstown	2 violations	Yes	1	A-
149	Carey	2 violations	Yes	2	B+
150	Hicksville	2 violations	Yes	2	B
151	Doylestown	2 violations	Yes	3	B-
152	North Baltimore	2 violations	Yes	7	A-
153	Fairport Harbor	2 violations	Yes	1	B+
154	Crooksville	2 violations	Yes	23	B
155	Strasburg	2 violations	Yes	1	B+
156	Gibsonburg	2 violations	Yes	1	B-
157	Sabina	2 violations	Yes	3	B-
158	Williamsburg	2 violations	Yes	6	B+
159	Middleport	2 violations	Yes	1	B
160	Dalton	2 violations	Yes	4	B+
161	Arcanum	2 violations	Yes	1	B+
162	Kalida	2 violations	Yes	6	A-
163	Pomeroy	2 violations	Yes	1	C
164	West Unity	2 violations	Yes	0	B
165	Mechanicsburg	2 violations	Yes	1	A-
166	Payne	2 violations	Yes	1	B+
167	Burton	2 violations	Yes	0	A-
168	Jeffersonville	2 violations	Yes	3	B-
169	Fayette	2 violations	Yes	0	A
170	Frazeysburg	2 violations	Yes	0	B+
171	Gnadenhutten	2 violations	Yes	5	C
172	Middletown	2 violations	Yes	0	A-
173	Walnut Creek	2 violations	Yes	3	B
174	New Vienna	2 violations	Yes	3	A-
175	Pleasant Hill	2 violations	Yes	0	A-
176	Ashley	2 violations	Yes	5	A-
177	Magnolia	2 violations	Yes	0	A
178	Yorkville	2 violations	Yes	1	C
179	Bradner	2 violations	Yes	1	A-
180	Philo	2 violations	Yes	2	B+
181	Bloomville	2 violations	Yes	1	A-
182	Perrysville	2 violations	Yes	3	B-
183	Addyston	2 violations	Yes	4	B
184	Bainbridge	2 violations	Yes	1	A
185	Cadia	2 violations	Yes	14	B
186	Marblehead	2 violations	Yes	5	A-
187	East Sparta	2 violations	Yes	0	A
188	New Holland	2 violations	Yes	0	A-
189	Flushing	2 violations	Yes	0	B-
190	Mcguffey	2 violations	Yes	3	B
191	Put-In-Bay	2 violations	Yes	28	B-
192	West Mansfield	2 violations	Yes	9	A
193	Racine	2 violations	Yes	2	A-
194	Rushsylvania	2 violations	Yes	5	B-
195	Clarksburg	2 violations	Yes	6	A
196	Marion	1 violations	Yes	9	B-
197	Struthers	1 violations	Yes	1	B+
198	Chillicothe	1 violations	Yes	0	B+
199	Pataskala	1 violations	Yes	4	B+
200	Huber Heights	1 violations	Yes	4	A-
201	Morrow	1 violations	Yes	7	B-
202	Jamestown	1 violations	Yes	4	B
203	Steubenville	1 violations	Yes	30	F
204	Huron	1 violations	Yes	13	C+
205	Whitehouse	1 violations	Yes	8	B
206	Norton	1 violations	Yes	17	A-
207	Gallipolis	1 violations	Yes	3	B
208	Miamisburg	1 violations	Yes	2	C
209	Avon Lake	1 violations	Yes	2	A-
210	Cambridge	1 violations	Yes	86	C-
211	Alliance	1 violations	Yes	17	B+
212	Waverly	1 violations	Yes	4	C+
213	Oregon	1 violations	Yes	1	B+
214	Springboro	1 violations	Yes	4	B+
215	Berea	1 violations	Yes	1	B+
216	New Philadelphia	1 violations	Yes	4	B
217	Englewood	1 violations	Yes	1	A-
218	Dover	1 violations	Yes	11	B
219	Bellefontaine	1 violations	Yes	5	B
220	Loveland	1 violations	Yes	0	B+
221	Conneaut	1 violations	Yes	6	B+
222	Wilmington	1 violations	Yes	26	B
223	Celina	1 violations	Yes	45	B-
224	Navarre	1 violations	Yes	8	C+
225	Oakwood	1 violations	Yes	10	C
226	Bellbrook	1 violations	Yes	2	B-
227	Wauseon	1 violations	Yes	22	C+
228	Cortland	1 violations	Yes	1	B+
229	Wellston	1 violations	Yes	18	B
230	Archbold	1 violations	Yes	16	B
231	Buckeye Lake	1 violations	Yes	2	B+
232	South Lebanon	1 violations	Yes	0	B+
233	Milford	1 violations	Yes	1	D
234	Upper Sandusky	1 violations	Yes	3	A-
235	Ontario	1 violations	Yes	0	A-
236	Rittman	1 violations	Yes	12	B
237	Clyde	1 violations	Yes	0	B+
238	Cleves	1 violations	Yes	1	A-
239	Obetz	1 violations	Yes	3	C-
240	New Carlisle	1 violations	Yes	5	B+
241	Caldwell	1 violations	Yes	33	D
242	Johnstown	1 violations	Yes	2	B+
243	St. Clairsville	1 violations	Yes	31	C
244	West Jefferson	1 violations	Yes	1	B+
245	Wellington	1 violations	Yes	5	A-
246	East Palestine	1 violations	Yes	0	A-
247	Lexington	1 violations	Yes	5	A-
248	Bellaire	1 violations	Yes	16	A-
249	South Point	1 violations	Yes	0	B+
250	Bellville	1 violations	Yes	9	C-
251	Bethel	1 violations	Yes	3	B
252	Yellow Springs	1 violations	Yes	1	B+
253	Mt Gilead	1 violations	Yes	2	B
254	Commercial Point	1 violations	Yes	0	A
255	Fredricktown	1 violations	Yes	2	C+
256	New Miami	1 violations	Yes	1	A-
257	Grafton	1 violations	Yes	29	B
258	Woodsfield	1 violations	Yes	14	B-
259	New Concord	1 violations	Yes	17	B+
260	Utica	1 violations	Yes	1	B
261	Southpoint	1 violations	Yes	2	A
262	Powhatan Point	1 violations	Yes	2	A-
263	Mount Sterling	1 violations	Yes	2	B+
264	Manchester	1 violations	Yes	1	C+
265	Winesburg	1 violations	Yes	6	B-
266	South Bloomfield	1 violations	Yes	7	B-
267	Berlin	1 violations	Yes	2	B
268	North Lewisburg	1 violations	Yes	9	B+
269	Mconnelsville	1 violations	Yes	4	A
270	Windham	1 violations	Yes	1	B+
271	Roaming Shores	1 violations	Yes	6	B+
272	Green Springs	1 violations	Yes	16	B
273	Newport	1 violations	Yes	1	B-
274	Felicity	1 violations	Yes	5	A-
275	Lithopolis	1 violations	Yes	4	B-
276	Fort Loramie	1 violations	Yes	3	A-
277	Greenwich	1 violations	Yes	1	B-
278	W Salem	1 violations	Yes	1	B
279	Monroeville	1 violations	Yes	2	A
280	Tiltonsville	1 violations	Yes	0	B+
281	Sardis	1 violations	Yes	0	B+
282	Pandora	1 violations	Yes	0	A
283	Ansonia	1 violations	Yes	6	B+
284	Tuscarawas	1 violations	Yes	0	A-
285	Wakeman	1 violations	Yes	21	B+
286	Kingston	1 violations	Yes	1	C
287	Danville	1 violations	Yes	3	A-
288	Gratis	1 violations	Yes	1	A-
289	Hopedale	1 violations	Yes	1	B
290	Pleasantville	1 violations	Yes	0	A-
291	Alger	1 violations	Yes	6	C
292	Butler	1 violations	Yes	0	B+
293	Dunkirk	1 violations	Yes	4	B
294	Sherwood	1 violations	Yes	0	B+
295	Rio Grande	1 violations	Yes	15	B+
296	Nevada	1 violations	Yes	0	B+
297	Scio	1 violations	Yes	4	B
298	Marshallville	1 violations	Yes	0	B+
299	Bettsville	1 violations	Yes	1	B+
300	Middleburg Heights	1 violations	Yes	2	A-
301	Rock Creek	1 violations	Yes	32	C-
302	Perrysburg	1 violations	Yes	4	C
303	Jewett	1 violations	Yes	1	B+
304	Lucas	1 violations	Yes	0	B
305	Quincy	1 violations	Yes	0	A-
306	Proctorville	1 violations	Yes	0	A
307	Republic	1 violations	Yes	4	B
308	Eldorado	1 violations	Yes	0	A-
309	North Fairfield	1 violations	Yes	0	B+
310	Gettysburg	1 violations	Yes	0	B+
311	Jeromesville	1 violations	Yes	0	A

FAQ

Frequently asked questions about nitrate in Ohio

Is nitrate in Ohio tap water dangerous?

Yes — 311 cities in Ohio 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 Ohio 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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