Colorado Water Quality — 246 Cities Tested

Latest water news in Colorado

Recent reporting on Colorado drinking water — boil-water advisories, regulatory action, and infrastructure events.

May 15, 2026

Colorado's Worst Snowpack on Record: Denver Stage 1, Erie Level 4 Emergency, Aurora Stage 1

Colorado snowpack hit record lows. Denver Water's first Stage 1 in 13 years, Erie came hours from running out, Aurora Stage 1. Front Range tightens.

Read full story →

Analysis

Colorado water quality overview

Colorado's drinking water quality is fair overall, with an average score of 66.1 out of 100 across 246 cities tested. The median score is 69.5, serving a total population of 7,181,473 residents. 38% of cities scored a D or F, pointing to significant water quality challenges in parts of the state. PFAS "forever chemicals" were detected in 67 of 246 cities tested (27%). 10 cities exceed the 2024 EPA maximum contaminant levels. 3 cities have lead levels exceeding the EPA action level of 15 ppb, often indicating aging infrastructure with lead service lines or lead solder. The state relies on a mix of water sources: 99 cities use groundwater while 147 draw from surface water such as rivers, lakes, and reservoirs.

Key Concerns

Issues to watch in Colorado

67 cities

PFAS Detected

27% of tested cities have PFAS in their water supply.

3 cities

Lead Exceedances

Lead levels above the EPA action level of 15 ppb (90th percentile).

206 cities

Health Violations

48,712 total violations recorded, 238 with unresolved issues.

39 cities

Failing Systems

Received a grade of F, indicating serious water quality issues.

Contaminant Data

Explore contaminants in Colorado

Lead in Colorado → Ranked by 90th percentile level (ppb) PFAS in Colorado → Ranked by compounds detected Copper in Colorado → Ranked by 90th percentile level (mg/L)

More contaminants tested in Colorado

HAA5 → Chromium-6 → Arsenic → Nitrate → Strontium → 1,4-Dioxane → Manganese → Vanadium → Chlorate → Molybdenum → Cobalt → Lithium → NDMA →

State context

21

Superfund sites in Colorado

EPA National Priorities List

75.2%

of Colorado residents on fluoridated water

CDC, 2020

1,241,620

lbs released to surface water

Top 10 TRI facilities, 2023

9.7%

of Colorado domestic wells exceed EPA arsenic limit

USGS, 1,170 samples · 10 µg/L MCL

Domestic well chemistry

Private-well water in Colorado

Based on USGS Powell Domestic-Well Database — 1,935 private wells sampled across Colorado. These wells are not regulated by the EPA; if you draw your tap from a private well, the public-system grade above does not apply to you.

1.5 µg/L

Median arsenic in domestic wells

P90 9.8 µg/L · max 104.0 µg/L

72 µg/L

Median manganese in domestic wells

28.6% exceed 300 µg/L aesthetic limit

Industrial pollution

Top industrial water polluters in Colorado

Industrial polluters nearby

The 10 facilities reporting the most pounds released to surface water in Colorado, 2023.

Total reported releases to surface water: 1,241,620 lbs

Facility	Top chemical	To surface water (lbs/yr)
CARGILL MEAT SOLUTIONS CORP Food · CARGILL INC FORT MORGAN, CO80701	Nitrate compounds (water dissociable; reportable only when in aqueous solution)	520,174
LEPRINO FOODS CO - GREELEY Food · LEPRINO FOODS CO GREELEY, CO80631	Nitrate compounds (water dissociable; reportable only when in aqueous solution)	409,556
MOLSON COORS USA LLC - GOLDEN BREWERY Beverages · MOLSON COORS BEVERAGE CO GOLDEN, CO80401	Nitrate compounds (water dissociable; reportable only when in aqueous solution)	146,000
US ARMY FORT CARSON (CANTONMENT) Other · US DEPARTMENT OF DEFENSE FORT CARSON, CO809134000	Nitrate compounds (water dissociable; reportable only when in aqueous solution)	100,561
CLIMAX MOLYBDENUM CO-HENDERSON MINE Metal Mining · FREEPORT-MCMORAN INC EMPIRE, CO80438	Nitrate compounds (water dissociable; reportable only when in aqueous solution)	32,000

+ 5 more facilities

Source: EPA Toxic Release Inventory (TRI) 2023

Test your own tap

Get your Colorado water tested

City-level data shows the source and infrastructure picture — but lead and other home-plumbing issues only show up at your tap. Find a state-certified lab, see what to test for, and what it costs.

Grade Distribution

How Colorado cities scored

A: 56 B: 63 C: 34 D: 54 F: 39

Best Cities

Worst Cities

City Map

Water quality across Colorado

Each dot is a city, colored by its water quality grade. Size reflects population served. Click any city to view its full water report.

All Cities

246 cities in Colorado

Full rankings →

#	City	Grade	Score	Population	Violations
1	Pelham	A+	96.8	1K	4
2	Northglenn	A+	95.6	49K	7
3	Gypsum	A+	95	15K	49
4	Sanford	A	94.2	850	52
5	Vail	A	93.9	52K	22
6	Niwot	A	93.7	20K	70
7	Commerce City	A	93.2	74K	0
8	Clifton	A	92.5	35K	16
9	Severance	A	92.3	12K	10
10	Des Plaines	A	92.3	702	9
11	Manitou Springs	A	92	7K	43
12	Erie	A	91.6	40K	38
13	Superior	A	91.5	18K	53
14	Eads	A	91.4	656	85
15	Tabernash	A	91.3	564	35
16	Byers	A	90.6	1K	8
17	Dubuque	A	90.4	548	8
18	Zion	A	90.3	624	8
19	Usaf Academy	A	90.2	17K	25
20	Pierce	A	90.2	1K	65
21	Edgewater	A-	89.8	5K	4
22	Bennett	A-	89.3	4K	19
23	Fort Morgan	A-	89.2	20K	49
24	Longmont	A-	89	107K	46
25	Louisville	A-	88.7	21K	42
26	Parachute	A-	88.7	2K	40
27	Penrose	A-	88.6	3K	24
28	Collbran	A-	88.6	678	7
29	Kersey	A-	88.3	2K	16
30	Dacono	A-	88.1	7K	8
31	New Castle	A-	88	6K	127
32	Diamond	A-	87.9	543	2
33	La Porte	A-	87.8	4K	18
34	Georgetown	A-	87.7	5K	38
35	Gainesville	A-	87.7	1K	23
36	Nederland	A-	87.6	2K	26
37	Swink	A-	87.6	660	15
38	Black Hawk	A-	87.5	15K	97
39	Simla	A-	87.3	618	20
40	Lake City	A-	87.2	654	20
41	Deer Trail	A-	87	2K	146
42	Firestone	A-	86.9	28K	16
43	Flagler	A-	86.8	2K	88
44	Hot Sulphur Springs	A-	86.8	687	27
45	Keenesburg	A-	86.7	5K	110
46	Poncha Springs	A-	86.7	1K	11
47	Hastings	A-	86.7	738	4
48	Center	A-	86.3	3K	37
49	Lochbuie	A-	86.2	7K	40
50	Limon	A-	86.2	6K	26
51	Mount Crested Butte	A-	86.2	4K	38
52	Kiowa	A-	85.8	910	26
53	Fort Carson	A-	85.7	48K	6
54	Delta	A-	85.7	9K	5
55	Silverton	A-	85.4	2K	11
56	Central City	A-	85.2	4K	17
57	Breckenridge	B+	84.9	28K	62
58	Gilcrest	B+	84.9	1K	7
59	Castle Pines	B+	84.8	13K	72
60	Federal Heights	B+	84.8	12K	1
61	Lucerne	B+	84.2	16K	1
62	Wray	B+	84.2	2K	34
63	Log Lane Village	B+	83.9	1K	22
64	Hillrose	B+	83.8	5K	22
65	Arvada	B+	83.5	173K	7
66	Conifer	B+	83.5	2K	66
67	Platteville	B+	83.4	3K	16
68	Canon City	B+	83	39K	78
69	Copper Mountain	B+	82.8	6K	3
70	Springfield	B+	82.8	1K	11
71	Minturn	B+	82.5	1K	16
72	Grand Lake	B+	82.3	3K	80
73	Nathrop	B+	82.2	638	107
74	Las Animas	B+	81.8	2K	38
75	Decatur	B+	81.7	500	10
76	Austin	B+	81.3	3K	23
77	Ault	B+	81.2	4K	7
78	West Columbia	B+	80.6	1K	16
79	Evans	B+	80	21K	22
80	Manassa	B	79.6	976	110
81	Grand Junction	B	79	119K	63
82	Johnstown	B	79	25K	94
83	Olathe	B	79	3K	5
84	Walden	B	78.9	652	17
85	La Jara	B	78.7	825	79
86	Broomfield	B	78.5	110K	60
87	Creede	B	78.2	2K	28
88	Cheyenne Wells	B	78	840	136
89	Rockvale	B	77.8	504	23
90	Craig	B	77.7	9K	41
91	Milliken	B	77.6	9K	117
92	Cripple Creek	B	77.5	3K	67
93	Dolores	B	77.4	15K	27
94	Elizabeth	B	77.3	5K	128
95	Akron	B	77.1	2K	77
96	Rock Springs	B	77	1K	35
97	Fowler	B	76.1	1K	46
98	Del Norte	B	75.9	1K	96
99	Williamsburg	B	75.8	775	37
100	Indian Hills	B	75.5	1K	34
101	Idaho Springs	B	75.2	10K	40
102	Lamar	B-	74.8	8K	140
103	Eaton	B-	74.6	7K	13
104	Westcliffe	B-	74.5	2K	20
105	Hugo	B-	74.4	885	41
106	Julesburg	B-	73.9	1K	19
107	Wellington	B-	73.8	16K	71
108	El Jebel	B-	73.8	2K	34
109	Frederick	B-	73.6	18K	19
110	Woodland	B-	73	9K	42
111	Mulberry	B-	73	764	30
112	Norwood	B-	72.8	2K	95
113	Snowmass Village	B-	72.7	6K	18
114	Crestone	B-	72.3	2K	77
115	Highlands Ranch	B-	71.5	105K	47
116	Moffat	B-	71.2	580	85
117	Pueblo West	B-	71	30K	64
118	Peyton	B-	71	14K	115
119	Golden	B-	70.5	55K	175
120	Morrison	C+	69.9	10K	167
121	Holyoke	C+	69.9	3K	50
122	Otis	C+	69.9	600	180
123	Rangely	C+	69.8	2K	66
124	Meeker	C+	69.5	3K	110
125	Debeque	C+	69.4	911	102
126	Lasalle	C+	69.2	2K	27
127	Florence	C+	68.8	8K	121
128	Ordway	C+	68.6	2K	114
129	Sedalia	C+	68.4	525	183
130	Empire	C+	68.1	500	52
131	Dillon	C+	67.8	9K	34
132	Eagle	C+	67.4	8K	134
133	Yuma	C+	65.5	4K	175
134	Berthoud	C+	65.2	40K	82
135	Kremmling	C	64.7	2K	64
136	Gunnison	C	63.7	11K	100
137	Edwards	C	63.5	2K	145
138	Mancos	C	62.7	3K	109
139	Keystone	C	61.9	11K	69
140	Fairplay	C	61.8	1K	114
141	Bailey	C	61.8	783	111
142	Haxtun	C	60.7	963	225
143	Dove Creek	C-	59	850	53
144	Naturita	C-	59	585	75
145	Clark	C-	59	511	107
146	Palisade	C-	57.9	3K	163
147	Stratton	C-	57.9	960	138
148	Crested Butte	C-	57.8	6K	241
149	Fraser	C-	57.5	5K	270
150	Ouray	C-	57.4	1K	114
151	Sterling	C-	56.6	15K	159
152	Granby	C-	55.8	5K	256
153	Burlington	C-	55.8	4K	317
154	Silverthorne	D+	54.1	12K	382
155	Ridgway	D+	53.7	1K	91
156	Walsh	D+	53.1	650	44
157	Wiley	D+	52	2K	627
158	Perth (T)	D+	52	500	750
159	Larkspur	D+	51.5	4K	95
160	Monte Vista	D+	51	5K	679
161	Woody Creek	D+	50.5	544	277
162	Wiggins	D+	50	2K	209
163	Calhan	D+	50	1K	372
164	Holly	D+	50	1K	244
165	Pine Bluffs	D+	50	1K	193
166	Pine Bluffs	D+	50	1K	193
167	Manzanola	D+	50	967	602
168	Saguache	D+	50	504	151
169	Englewood	D	49.8	100K	203
170	Aspen	D	49.5	33K	210
171	Falcon	D	49.2	19K	681
172	Hayden	D	49.2	4K	144
173	Basalt	D	49	8K	529
174	Bayfield	D	49	6K	365
175	Walsenburg	D	49	4K	390
176	Watkins	D	49	4K	159
177	Oak Creek	D	49	2K	132
178	Beulah	D	49	927	220
179	Windsor	D	48.8	30K	1144
180	Paonia	D	48.5	4K	561
181	Redvale	D	48	10K	181
182	Hudson	D	48	4K	973
183	Leadville	D	47.5	8K	500
184	Alamosa	D	47.2	13K	476
185	Cortez	D	47.2	10K	158
186	Winter Park	D	47	12K	272
187	Strasburg	D	47	2K	181
188	Fort Collins	D	46.8	304K	121
189	Estes Park	D	46.4	22K	225
190	Rifle	D	46.2	11K	404
191	Westminster	D	46	204K	115
192	Trinidad	D	46	13K	288
193	Glendale	D	46	7K	213
194	Woodland Park	D	46	2K	523
195	San Luis	D	46	1K	242
196	South Fork	D	46	1K	255
197	Rye	D	46	745	257
198	Salida	D	45.8	6K	225
199	Wheat Ridge	D	45	41K	347
200	Fort Lupton	D	45	14K	162
201	Cedaredge	D	45	9K	513
202	Telluride	D	45	9K	400
203	Lyons	D	45	4K	116
204	Palmer Lake	D	45	3K	151
205	Towoac	D	45	2K	436
206	Nucla	D	45	875	134
207	Granada	D	45	515	238
208	Divide	F	44.5	3K	837
209	Greeley	F	44.1	141K	166
210	Frisco	F	44	5K	546
211	Loveland	F	43.8	98K	336
212	Buena Vista	F	43.5	7K	526
213	Boulder	F	43.4	171K	116
214	Parker	F	43.4	105K	499
215	La Junta	F	43.2	10K	715
216	Administrative Contact	F	43.2	4K	383
217	Silt	F	43	4K	173
218	Lafayette	F	42.6	32K	461
219	Steamboat Springs	F	42.6	30K	607
220	Montrose	F	42.2	52K	474
221	Carbondale	F	42.2	8K	1470
222	Pagosa Springs	F	42	12K	285
223	Colorado City	F	42	3K	132
224	Ft Morgan	F	42	705	176
225	Fountain	F	41.9	26K	204
226	La Veta	F	41.9	1K	141
227	Monument	F	41.8	31K	341
228	Evergreen	F	41.8	17K	178
229	Antonito	F	41.5	1K	399
230	Glenwood Springs	F	41	17K	515
231	Crawford	F	41	1K	520
232	Pueblo	F	40.9	128K	363
233	Littleton	F	40.9	127K	341
234	Greenwood Village	F	40.2	20K	268
235	Castle Rock	F	40	116K	259
236	Denver	F	39.6	1.4M	1182
237	Aurora	F	38.1	604K	1430
238	Thornton	F	38	233K	139
239	Durango	F	38	47K	1724
240	Ignacio	F	38	3K	156
241	Lakewood	F	36.9	252K	591
242	Centennial	F	36.8	106K	298
243	Brighton	F	36	65K	337
244	Colorado Springs	F	33.5	572K	2519
245	Hotchkiss	F	31	4K	957
246	Rocky Ford	F	29.2	6K	726

Counties

Browse Colorado counties

Adams 9 cities · avg 68.5 Alachua 1 city · avg 87.7 Alamosa 1 city · avg 47.2 Arapahoe 9 cities · avg 53.2 Archuleta 1 city · avg 42 Baca 2 cities · avg 68 Bent 1 city · avg 81.8 Boulder 9 cities · avg 74.8 Broomfield 1 city · avg 78.5 Chaffee 4 cities · avg 64.5 Cheyenne 1 city · avg 78 Clear Creek 3 cities · avg 77 Conejos 4 cities · avg 73.5 Cook 1 city · avg 92.3 Costilla 1 city · avg 46 Crowley 1 city · avg 68.6 Custer 1 city · avg 74.5 Delta 6 cities · avg 55.4 Denver 1 city · avg 39.6 Dolores 1 city · avg 59 Douglas 6 cities · avg 59.9 Dubuque 1 city · avg 90.4 Eagle 7 cities · avg 75 El Paso 10 cities · avg 60 Elbert 3 cities · avg 83.5 Fremont 5 cities · avg 78.8 Fulton 1 city · avg 52 Garfield 7 cities · avg 56 Gilpin 2 cities · avg 86.3 Grand 7 cities · avg 69.3 Grundy 1 city · avg 87.9 Gunnison 3 cities · avg 69.2 Hinsdale 1 city · avg 87.2 Huerfano 2 cities · avg 45.5 Jackson 1 city · avg 78.9 Jefferson 9 cities · avg 66.3 Kiowa 1 city · avg 91.4 Kit Carson 3 cities · avg 66.8 La Plata 3 cities · avg 41.7 Lake 2 cities · avg 68.9 Laramie 2 cities · avg 50 Larimer 7 cities · avg 58 Las Animas 1 city · avg 46 Lexington 1 city · avg 80.6 Lincoln 2 cities · avg 80.3 Logan 1 city · avg 56.6 Macon 1 city · avg 81.7 Mesa 5 cities · avg 77.5 Mineral 1 city · avg 78.2 Moffat 1 city · avg 77.7 Montezuma 3 cities · avg 62.4 Montrose 4 cities · avg 56.3 Morgan 4 cities · avg 76.7 Otero 5 cities · avg 57.2 Ouray 2 cities · avg 55.5 Park 2 cities · avg 61.8 Phillips 2 cities · avg 65.3 Pitkin 3 cities · avg 57.6 Polk 1 city · avg 73 Prowers 4 cities · avg 55.5 Pueblo 5 cities · avg 49.8 Rio Blanco 2 cities · avg 69.7 Rio Grande 3 cities · avg 57.6 Routt 4 cities · avg 50 Saguache 4 cities · avg 70 San Juan 1 city · avg 85.4 San Miguel 3 cities · avg 55.3 Sedgwick 1 city · avg 73.9 Shelby 1 city · avg 96.8 Summit 6 cities · avg 65.9 Sweetwater 1 city · avg 77 Teller 4 cities · avg 60.3 Washington 2 cities · avg 73.5 Weld 21 cities · avg 75.8 Yuma 2 cities · avg 74.8

ZIP Codes

Browse Colorado by ZIP code

Look up water quality by ZIP code to find the systems serving your area.

View all Colorado ZIP codes →

FAQ

Frequently asked questions about Colorado's water

Is Colorado's tap water safe to drink?

Colorado's water quality varies by city. The statewide average grade is C+ (66.1/100). 48% of cities scored an A or B, while 38% received a D or F. Check your specific city for detailed results.

Which Colorado cities have the best water quality?

The top-rated cities are Pelham (A+), Northglenn (A+), Gypsum (A+). These cities scored highest based on violation history, lead levels, PFAS contamination, and regulatory compliance.

Which Colorado cities have the worst water quality?

The lowest-rated cities are Rocky Ford (F), Hotchkiss (F), Colorado Springs (F). We recommend residents in these areas consider water filtration and review their city's specific contaminant data.

How many Colorado cities have PFAS in their water?

67 out of 246 cities tested positive for PFAS "forever chemicals" (27%). 10 cities exceed the 2024 EPA maximum contaminant levels. Reverse osmosis or activated carbon filters can help reduce PFAS exposure.

Do any Colorado cities have dangerous lead levels?

3 cities exceed the EPA lead action level of 15 ppb. Lead contamination typically comes from aging pipes and lead service lines rather than the water source itself. An NSF 53-certified filter can effectively remove lead from tap water.

Colorado Water Quality Report