Nitrate Contamination

Nitrate in Wyoming Drinking Water

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

Cities Tested

Has Violations

100%

% Has Violations

8.7 violations

State Avg

▼ 0% vs national

vs National

Health Violations

Analysis

Nitrate in Wyoming: what the data shows

Wyoming has 53 cities with nitrate-related violations. The EPA MCL for nitrate is 10 mg/L (measured as nitrogen). The state has 53 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

Wyoming

100%

53 of 53 cities

← = Exactly at national rate

National avg

100%

8001 of 8001 cities

City Map

Nitrate data across Wyoming

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 Wyoming

Highest Nitrate levels (violations)

All Cities

All Wyoming cities ranked by nitrate level

#	City	Level	Violations?	Violations	Grade
1	Jackson	63 violations	Yes	64	F
2	Torrington	50 violations	Yes	63	F
3	Cheyenne	40 violations	Yes	36	F
4	Gillette	35 violations	Yes	89	F
5	Fort Washakie	25 violations	Yes	40	F
6	Riverton	17 violations	Yes	59	F
7	Marbleton	17 violations	Yes	4	D+
8	Ethete	14 violations	Yes	8	B-
9	Afton	13 violations	Yes	34	D+
10	Mills	11 violations	Yes	14	F
11	Alpine	11 violations	Yes	7	D+
12	Douglas	10 violations	Yes	11	C
13	Wheatland	9 violations	Yes	22	C+
14	Encampment	9 violations	Yes	12	B+
15	Farson	9 violations	Yes	2	B-
16	Cokeville	9 violations	Yes	8	D+
17	Buffalo	8 violations	Yes	19	B-
18	Casper	7 violations	Yes	22	F
19	Newcastle	6 violations	Yes	20	D
20	Thayne	6 violations	Yes	17	D
21	Wilson	6 violations	Yes	1	D
22	Greybull	5 violations	Yes	2	B
23	Saratoga	5 violations	Yes	7	B
24	Laramie	4 violations	Yes	6	C-
25	Cody	4 violations	Yes	3	B-
26	Evanston	4 violations	Yes	12	B+
27	Thermopolis	4 violations	Yes	13	D
28	Lusk	4 violations	Yes	12	C+
29	Dayton	4 violations	Yes	3	A-
30	Sheridan	3 violations	Yes	16	F
31	Worland	3 violations	Yes	1	A-
32	Lyman	3 violations	Yes	7	A-
33	Evansville	3 violations	Yes	1	B+
34	Pinedale	3 violations	Yes	18	B+
35	Burns	3 violations	Yes	10	B-
36	Hanna	3 violations	Yes	2	A-
37	Cowley	3 violations	Yes	4	A-
38	Yellowstone Np	2 violations	Yes	13	D
39	Rawlins	2 violations	Yes	7	C-
40	Lovell	2 violations	Yes	4	B
41	Thayne	2 violations	Yes	7	B
42	Little America	2 violations	Yes	36	C+
43	Dubois	2 violations	Yes	2	C
44	Sundance	2 violations	Yes	10	A-
45	Ranchester	2 violations	Yes	1	A
46	Guernsey	2 violations	Yes	9	A-
47	Smoot	2 violations	Yes	8	A-
48	Shoshoni	2 violations	Yes	3	A-
49	Wamsutter	2 violations	Yes	4	A-
50	Rock Springs	1 violations	Yes	5	C
51	Lander	1 violations	Yes	3	B+
52	Kemmerer	1 violations	Yes	21	D+
53	Glenrock	1 violations	Yes	3	A-

FAQ

Frequently asked questions about nitrate in Wyoming

Is nitrate in Wyoming tap water dangerous?

Yes — 53 cities in Wyoming 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 Wyoming 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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