Nitrate Contamination

Nitrate in Maryland Drinking Water

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

Cities Tested

Has Violations

100%

% Has Violations

6.0 violations

State Avg

▼ 0% vs national

vs National

Health Violations

Analysis

Nitrate in Maryland: what the data shows

Maryland has 85 cities with nitrate-related violations. The EPA MCL for nitrate is 10 mg/L (measured as nitrogen). The state has 85 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

Maryland

100%

85 of 85 cities

← = Exactly at national rate

National avg

100%

8001 of 8001 cities

City Map

Nitrate data across Maryland

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 Maryland

Highest Nitrate levels (violations)

All Cities

All Maryland cities ranked by nitrate level

#	City	Level	Violations?	Violations	Grade
1	Ellicott City	48 violations	Yes	56	D
2	Port Deposit	35 violations	Yes	31	F
3	North East	27 violations	Yes	95	F
4	Hebron	27 violations	Yes	28	A-
5	Waldorf	20 violations	Yes	8	D
6	Salisbury	18 violations	Yes	26	F
7	Frederick	17 violations	Yes	18	F
8	La Plata	15 violations	Yes	10	F
9	Westminster	13 violations	Yes	29	F
10	Indian Head	13 violations	Yes	2	B-
11	Poolesville	13 violations	Yes	3	B
12	Boonsboro	13 violations	Yes	23	C+
13	Berlin	11 violations	Yes	6	D
14	Havre De Grace	11 violations	Yes	13	C
15	Elkton	10 violations	Yes	42	F
16	Denton	10 violations	Yes	13	B-
17	Fruitland	9 violations	Yes	14	C+
18	Woodsboro	8 violations	Yes	1	A-
19	California	7 violations	Yes	2	C-
20	Stevensville	7 violations	Yes	6	C
21	Federalsburg	7 violations	Yes	9	C
22	Street	7 violations	Yes	2	B-
23	Ocean City	6 violations	Yes	15	C-
24	Delmar	6 violations	Yes	13	B+
25	Leonardtown	6 violations	Yes	5	B-
26	Snow Hill	6 violations	Yes	4	B+
27	Mount Airy	5 violations	Yes	4	C+
28	Hampstead	5 violations	Yes	2	B+
29	Manchester	5 violations	Yes	4	B+
30	Princess Anne	5 violations	Yes	2	B
31	Sykesville	5 violations	Yes	23	C-
32	Ridgely	5 violations	Yes	5	B-
33	Sharptown	5 violations	Yes	20	B+
34	Millersville	4 violations	Yes	13	F
35	Patuxent River	4 violations	Yes	2	A-
36	Chestertown	4 violations	Yes	3	C
37	Emmitsburg	4 violations	Yes	44	B
38	Greensboro	4 violations	Yes	1	D+
39	Queenstown	4 violations	Yes	2	B+
40	Hagerstown	3 violations	Yes	42	C
41	Dunkirk	3 violations	Yes	1	A-
42	Walkersville	3 violations	Yes	10	A-
43	Lonaconing	3 violations	Yes	9	C+
44	Perryville	3 violations	Yes	48	D
45	Middletown	3 violations	Yes	6	B
46	Willards	3 violations	Yes	1	B+
47	Centreville	3 violations	Yes	5	B
48	Lothian	3 violations	Yes	3	B-
49	Hancock	3 violations	Yes	2	B
50	New Windsor	3 violations	Yes	3	A-
51	Oxford	3 violations	Yes	4	B
52	Columbia	2 violations	Yes	50	C+
53	Abingdon	2 violations	Yes	0	A
54	Thurmont	2 violations	Yes	4	B+
55	Pocomoke City	2 violations	Yes	12	B-
56	Hurlock	2 violations	Yes	3	B
57	Jessup	2 violations	Yes	1	B
58	Union Bridge	2 violations	Yes	3	A-
59	Glen Arm	2 violations	Yes	9	C+
60	Brandywine	2 violations	Yes	0	A-
61	Grasonville	2 violations	Yes	2	B-
62	Secretary	2 violations	Yes	15	A-
63	Huntingtown	2 violations	Yes	7	B-
64	Baltimore	1 violations	Yes	12	F
65	Fort Meade	1 violations	Yes	3	A
66	Annapolis	1 violations	Yes	3	A-
67	Bowie	1 violations	Yes	1	B+
68	Easton	1 violations	Yes	6	A-
69	Prince Frederick	1 violations	Yes	4	B
70	Lusby	1 violations	Yes	3	B
71	Brunswick	1 violations	Yes	4	A-
72	Lavale	1 violations	Yes	3	B
73	Chesapeake Beach	1 violations	Yes	0	A-
74	Williamsport	1 violations	Yes	8	C+
75	Smithsburg	1 violations	Yes	19	B
76	St Michaels	1 violations	Yes	9	B+
77	Severn	1 violations	Yes	3	B-
78	Westernport	1 violations	Yes	5	B
79	Perry Point	1 violations	Yes	18	B+
80	Pittsville	1 violations	Yes	5	B+
81	Timonium	1 violations	Yes	3	B+
82	Funkstown	1 violations	Yes	1	A-
83	Crofton	1 violations	Yes	0	B
84	Preston	1 violations	Yes	2	B+
85	Millington	1 violations	Yes	0	A-

FAQ

Frequently asked questions about nitrate in Maryland

Is nitrate in Maryland tap water dangerous?

Yes — 85 cities in Maryland 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 Maryland 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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