Colorado Water Quality — 244 Cities Tested

Latest water news in Colorado

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

Jun 20, 2026

Colorado Declares Statewide Drought Emergency as Lake Powell Nears Hydropower Cutoff

Colorado declared a statewide drought emergency June 4 as Lake Powell may fall below its 3,490-ft minimum power pool by August 2026.

Read full story →

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 244 cities tested. The median score is 69.5, serving a total population of 7,164,906 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 244 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: 97 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).

205 cities

Health Violations

47,958 total violations recorded, 236 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: 55 B: 63 C: 34 D: 53 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

244 cities in Colorado

Full rankings →

#	City	Grade	Score	Population	Violations
1	Pelham	A+	96.8	966	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	106K	46
25	Louisville	A-	88.7	21K	42
26	Parachute	A-	88.7	1K	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	Center	A-	86.3	3K	37
48	Lochbuie	A-	86.2	7K	40
49	Limon	A-	86.2	6K	26
50	Mount Crested Butte	A-	86.2	4K	38
51	Kiowa	A-	85.8	910	26
52	Fort Carson	A-	85.7	48K	6
53	Delta	A-	85.7	9K	5
54	Silverton	A-	85.4	2K	11
55	Central City	A-	85.2	4K	17
56	Breckenridge	B+	84.9	28K	62
57	Gilcrest	B+	84.9	1K	7
58	Castle Pines	B+	84.8	13K	72
59	Federal Heights	B+	84.8	12K	1
60	Lucerne	B+	84.2	16K	1
61	Wray	B+	84.2	2K	34
62	Log Lane Village	B+	83.9	1K	22
63	Hillrose	B+	83.8	5K	22
64	Arvada	B+	83.5	173K	7
65	Conifer	B+	83.5	2K	66
66	Platteville	B+	83.4	3K	16
67	Canon City	B+	83	39K	78
68	Copper Mountain	B+	82.8	6K	3
69	Springfield	B+	82.8	1K	11
70	Minturn	B+	82.5	1K	16
71	Grand Lake	B+	82.3	3K	80
72	Nathrop	B+	82.2	638	107
73	Las Animas	B+	81.8	2K	38
74	Decatur	B+	81.7	500	10
75	Austin	B+	81.3	3K	23
76	Ault	B+	81.2	4K	7
77	West Columbia	B+	80.6	1K	16
78	Evans	B+	80	21K	22
79	Manassa	B	79.6	976	110
80	Grand Junction	B	79	119K	63
81	Johnstown	B	79	25K	94
82	Olathe	B	79	3K	5
83	Walden	B	78.9	652	17
84	La Jara	B	78.7	825	79
85	Broomfield	B	78.5	110K	60
86	Creede	B	78.2	2K	28
87	Cheyenne Wells	B	78	840	136
88	Rockvale	B	77.8	504	23
89	Craig	B	77.7	9K	41
90	Milliken	B	77.6	9K	117
91	Cripple Creek	B	77.5	3K	67
92	Dolores	B	77.4	15K	27
93	Elizabeth	B	77.3	5K	128
94	Akron	B	77.1	2K	77
95	Rock Springs	B	77	700	35
96	Fowler	B	76.1	1K	46
97	Del Norte	B	75.9	1K	96
98	Williamsburg	B	75.8	775	37
99	Indian Hills	B	75.5	1K	34
100	Idaho Springs	B	75.2	10K	40
101	Lamar	B-	74.8	8K	140
102	Eaton	B-	74.6	7K	13
103	Westcliffe	B-	74.5	2K	20
104	Hugo	B-	74.4	885	41
105	Julesburg	B-	73.9	1K	19
106	Wellington	B-	73.8	16K	71
107	El Jebel	B-	73.8	2K	34
108	Frederick	B-	73.6	18K	19
109	Woodland	B-	73	9K	42
110	Mulberry	B-	73	764	30
111	Norwood	B-	72.8	2K	95
112	Snowmass Village	B-	72.7	6K	18
113	Crestone	B-	72.3	2K	77
114	Highlands Ranch	B-	71.5	105K	47
115	Moffat	B-	71.2	580	85
116	Pueblo West	B-	71	30K	64
117	Peyton	B-	71	14K	115
118	Golden	B-	70.5	53K	175
119	Morrison	C+	69.9	10K	167
120	Holyoke	C+	69.9	3K	50
121	Otis	C+	69.9	600	180
122	Rangely	C+	69.8	2K	66
123	Meeker	C+	69.5	3K	110
124	Debeque	C+	69.4	911	102
125	Lasalle	C+	69.2	2K	27
126	Florence	C+	68.8	8K	121
127	Ordway	C+	68.6	2K	114
128	Sedalia	C+	68.4	525	183
129	Empire	C+	68.1	500	52
130	Dillon	C+	67.8	9K	34
131	Eagle	C+	67.4	8K	134
132	Yuma	C+	65.5	4K	175
133	Berthoud	C+	65.2	40K	82
134	Kremmling	C	64.7	2K	64
135	Gunnison	C	63.7	11K	100
136	Edwards	C	63.5	2K	145
137	Mancos	C	62.7	3K	109
138	Keystone	C	61.9	11K	69
139	Fairplay	C	61.8	1K	114
140	Bailey	C	61.8	783	111
141	Haxtun	C	60.7	963	225
142	Dove Creek	C-	59	850	53
143	Naturita	C-	59	585	75
144	Clark	C-	59	511	107
145	Palisade	C-	57.9	3K	163
146	Stratton	C-	57.9	960	138
147	Crested Butte	C-	57.8	6K	241
148	Fraser	C-	57.5	5K	270
149	Ouray	C-	57.4	1K	114
150	Sterling	C-	56.6	15K	159
151	Granby	C-	55.8	5K	256
152	Burlington	C-	55.8	4K	317
153	Silverthorne	D+	54.1	12K	382
154	Ridgway	D+	53.7	1K	91
155	Walsh	D+	53.1	650	44
156	Wiley	D+	52	2K	627
157	Larkspur	D+	51.5	4K	95
158	Monte Vista	D+	51	5K	679
159	Woody Creek	D+	50.5	544	277
160	Wiggins	D+	50	2K	209
161	Calhan	D+	50	1K	372
162	Holly	D+	50	1K	244
163	Pine Bluffs	D+	50	1K	193
164	Pine Bluffs	D+	50	1K	193
165	Manzanola	D+	50	967	602
166	Saguache	D+	50	504	151
167	Englewood	D	49.8	100K	203
168	Aspen	D	49.5	33K	210
169	Falcon	D	49.2	19K	681
170	Hayden	D	49.2	4K	144
171	Basalt	D	49	8K	529
172	Bayfield	D	49	6K	365
173	Walsenburg	D	49	4K	390
174	Watkins	D	49	4K	159
175	Oak Creek	D	49	2K	132
176	Beulah	D	49	927	220
177	Windsor	D	48.8	30K	1144
178	Paonia	D	48.5	4K	561
179	Redvale	D	48	10K	181
180	Hudson	D	48	4K	973
181	Leadville	D	47.5	8K	500
182	Alamosa	D	47.2	13K	476
183	Cortez	D	47.2	10K	158
184	Winter Park	D	47	12K	272
185	Strasburg	D	47	2K	181
186	Fort Collins	D	46.8	304K	121
187	Estes Park	D	46.4	22K	225
188	Rifle	D	46.2	11K	404
189	Westminster	D	46	204K	115
190	Trinidad	D	46	13K	288
191	Glendale	D	46	7K	213
192	Woodland Park	D	46	2K	523
193	San Luis	D	46	1K	242
194	South Fork	D	46	1K	255
195	Rye	D	46	745	257
196	Salida	D	45.8	6K	225
197	Wheat Ridge	D	45	41K	347
198	Fort Lupton	D	45	14K	162
199	Cedaredge	D	45	9K	513
200	Telluride	D	45	9K	400
201	Lyons	D	45	4K	116
202	Palmer Lake	D	45	3K	151
203	Towoac	D	45	2K	436
204	Nucla	D	45	875	134
205	Granada	D	45	515	238
206	Divide	F	44.5	3K	837
207	Greeley	F	44.1	141K	166
208	Frisco	F	44	5K	546
209	Loveland	F	43.8	97K	336
210	Buena Vista	F	43.5	7K	526
211	Boulder	F	43.4	170K	116
212	Parker	F	43.4	105K	499
213	La Junta	F	43.2	10K	715
214	Administrative Contact	F	43.2	4K	383
215	Silt	F	43	4K	173
216	Lafayette	F	42.6	32K	461
217	Steamboat Springs	F	42.6	30K	607
218	Montrose	F	42.2	52K	474
219	Carbondale	F	42.2	8K	1470
220	Pagosa Springs	F	42	12K	285
221	Colorado City	F	42	3K	132
222	Ft Morgan	F	42	705	176
223	Fountain	F	41.9	26K	204
224	La Veta	F	41.9	1K	141
225	Monument	F	41.8	31K	341
226	Evergreen	F	41.8	17K	178
227	Antonito	F	41.5	1K	399
228	Glenwood Springs	F	41	17K	515
229	Crawford	F	41	1K	520
230	Littleton	F	40.9	127K	341
231	Pueblo	F	40.9	127K	363
232	Greenwood Village	F	40.2	20K	268
233	Castle Rock	F	40	116K	259
234	Denver	F	39.6	1.4M	1182
235	Aurora	F	38.1	603K	1430
236	Thornton	F	38	231K	139
237	Durango	F	38	47K	1724
238	Ignacio	F	38	3K	156
239	Lakewood	F	36.9	252K	591
240	Centennial	F	36.8	106K	298
241	Brighton	F	36	65K	337
242	Colorado Springs	F	33.5	567K	2519
243	Hotchkiss	F	31	4K	957
244	Rocky Ford	F	29.2	6K	726

Counties

Browse Colorado counties

Adams 8 cities · avg 66.2 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 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 244 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