Colorado Tap Water Quality Report

327 cities analyzed • 5,361,715 people served

Updated March 2026 • Data from EWG & EPA SDWIS

327

Cities Analyzed

9.4

Avg Above Guidelines

5,361,715

Total Population Served

Best Water Quality

Pine (0 above guidelines)

Most Concerns

Thornton (22 above guidelines)

Most Common Contaminants in Colorado

Contaminant	Found In	% of Cities
Total trihalomethanes (TTHMs) carcinogen	288 of 327	88%
Bromodichloromethane carcinogen	262 of 327	80%
Haloacetic acids (HAA5) carcinogen	259 of 327	79%
Barium	248 of 327	76%
Chloroform carcinogen	246 of 327	75%
Dibromochloromethane carcinogen	242 of 327	74%
Nitrate carcinogen	231 of 327	71%
Fluoride	221 of 327	68%
Dichloroacetic acid carcinogen	210 of 327	64%
Radium, combined (-226 and -228)	195 of 327	60%

City-by-City Water Quality Rankings

Ranked by number of contaminants above EWG health guidelines (most to fewest).

#	City	Detected	Above Guidelines	Above Legal	People Served
1	Thornton	37	22	0	155,700
2	Brighton	40	20	2	55,201
3	Farmington Hills	40	20	2	1,500
4	Aurora	38	18	0	314,346
5	Englewood	33	18	0	57,332
6	Fountain	32	18	3	25,130
7	Sterling	30	18	1	15,100
8	Frisco	26	18	0	4,495
9	Indian Hills	28	18	2	1,300
10	Castle Rock	29	17	0	99,757
11	Rocky Ford	25	17	1	4,443
12	Keenesburg	27	17	1	3,600
13	Fowler	25	17	0	0
14	Pueblo West	29	16	0	30,000
15	Vail	32	16	0	19,351
16	Black Hawk	29	16	0	15,167
17	Keystone	22	16	1	9,900
18	Lochbuie	26	16	2	6,830
19	Commerce City	32	15	0	68,603
20	Parker	38	15	0	59,781
21	La Junta	18	15	1	9,200
22	Avondale	23	15	0	1,615
23	Wiggins	18	15	0	135
24	Gunnison	22	14	0	9,610
25	Dillon	16	14	0	2,501
26	Colorado City	24	14	2	2,175
27	Parachute	19	14	0	1,320
28	Divide	21	14	1	875
29	Woodland Park	18	14	1	600
30	Olney Springs	22	14	1	399
31	Lazear	18	14	0	178
32	Kiowa	18	14	0	0
33	Karval	20	14	0	0
34	Log Lane Village	19	14	0	0
35	Arvada	26	13	0	146,743
36	Highlands Ranch	31	13	0	103,444
37	Canon City	22	13	0	34,800
38	Lafayette	28	13	0	28,700
39	Federal Heights	30	13	0	11,678
40	Wellington	27	13	0	11,500
41	Milliken	19	13	0	9,160
42	Watkins	20	13	0	1,433
43	Collbran	17	13	0	661
44	Walden	19	13	0	584
45	Brookside	22	13	0	438
46	Livermore	16	13	0	395
47	Boone	17	13	0	350
48	Mesa	17	13	0	300
49	Florissant	18	13	0	250
50	Westminster	23	12	0	192,878
51	Broomfield	23	12	0	106,153
52	Loveland	23	12	0	76,378
53	Golden	23	12	0	29,635
54	Berthoud	20	12	0	21,779
55	Pagosa Springs	27	12	0	11,069
56	Brush	13	12	0	5,117
57	Fraser	15	12	0	3,250
58	Penrose	16	12	0	3,149
59	Granby	17	12	0	2,300
60	Conifer	18	12	0	1,941
61	Ordway	16	12	0	1,300
62	Hotchkiss	19	12	0	840
63	Ft Morgan	17	12	1	300
64	Peetz	16	12	0	295
65	Irvine	12	12	0	229
66	Red Feather Lakes	17	12	0	90
67	Tabernash	12	12	0	0
68	Silver Plume	16	12	0	0
69	Aguilar	17	12	0	0
70	Hugo	17	12	0	0
71	Denver	26	11	0	1,287,000
72	Centennial	26	11	0	55,000
73	Littleton	26	11	0	48,648
74	Fort Carson	30	11	0	48,000
75	Lakewood	26	11	0	44,000
76	Aspen	19	11	0	31,100
77	Breckenridge	22	11	0	28,315
78	Louisville	21	11	0	20,975
79	Wheat Ridge	26	11	0	20,000
80	Evans	27	11	0	19,369
81	Superior	17	11	0	17,170
82	Lucerne	24	11	0	13,000
83	Trinidad	19	11	0	11,400
84	Morrison	20	11	0	9,887
85	Rifle	20	11	0	9,489
86	Greenwood Village	26	11	0	9,215
87	Peyton	19	11	0	8,814
88	Woodland	16	11	0	8,500
89	Falcon	17	11	0	8,474
90	Silverthorne	19	11	0	8,414
91	Copper Mountain	15	11	0	5,785
92	Edgewater	26	11	0	5,300
93	Basalt	16	11	0	4,500
94	Glendale	26	11	0	4,400
95	Silt	18	11	0	3,536
96	Meeker	14	11	0	2,500
97	Palmer Lake	22	11	0	2,450
98	Grand Lake	16	11	0	2,035
99	Poncha Springs	18	11	0	1,467
100	Elizabeth	16	11	0	1,435
101	Byers	15	11	0	1,000
102	Debeque	20	11	0	911
103	Hartsel	15	11	0	900
104	Swink	15	11	0	660
105	Simla	15	11	0	618
106	Otis	15	11	0	600
107	Bailey	16	11	0	483
108	Hoehne	19	11	0	312
109	Cokedale	19	11	0	120
110	Clark	14	11	0	100
111	Lake George	15	11	0	86
112	La Porte	23	11	0	0
113	Branson	14	11	0	0
114	Julesburg	16	11	0	0
115	Burlington	16	11	0	0
116	Colorado Springs	26	10	0	464,111
117	Fort Collins	23	10	0	179,901
118	Greeley	25	10	0	108,000
119	Northglenn	24	10	0	48,927
120	Clifton	21	10	0	34,500
121	Steamboat Springs	20	10	0	16,980
122	Usaf Academy	27	10	0	16,876
123	Estes Park	18	10	0	16,722
124	Fort Morgan	17	10	0	12,000
125	Redvale	16	10	0	8,700
126	Gypsum	15	10	0	7,764
127	Leadville	14	10	0	7,500
128	Florence	21	10	0	7,495
129	Eagle	16	10	0	6,961
130	Carbondale	17	10	0	6,700
131	Eaton	17	10	0	6,000
132	New Castle	16	10	0	5,024
133	Yuma	16	10	0	4,049
134	Buena Vista	13	10	0	3,776
135	Palisade	13	10	0	3,060
136	Paonia	15	10	0	2,499
137	Bayfield	15	10	0	2,300
138	Minturn	13	10	0	1,200
139	Pierce	16	10	0	850
140	Cheyenne Wells	14	10	0	840
141	Holly	15	10	0	800
142	Williamsburg	22	10	0	775
143	Edwards	16	10	0	767
144	Deer Trail	17	10	0	700
145	South Fork	15	10	0	566
146	Rockvale	21	10	0	504
147	Nunn	16	10	0	480
148	Ft Collins	15	10	0	425
149	Hesperus	18	10	0	354
150	Coal Creek	22	10	0	350
151	Walsenburg	14	10	0	341
152	Woody Creek	16	10	0	324
153	York	20	10	0	289
154	Antonito	13	10	0	176
155	Kim	13	10	0	116
156	Somerset	18	10	0	100
157	Haswell	14	10	0	55
158	Wetmore	20	10	0	38
159	Steamboat	15	10	0	30
160	Akron	19	10	0	0
161	Castle Pines	13	10	0	0
162	Two Buttes	14	10	0	0
163	Vona	14	10	0	0
164	Ault	17	10	0	0
165	Battlement Mesa	17	10	0	0
166	Del Norte	12	10	0	0
167	Walsh	13	10	0	0
168	Ovid	13	10	0	0
169	Severance	16	10	0	0
170	Hot Sulphur Springs	18	10	0	0
171	Vilas	15	10	0	0
172	Grand Junction	16	9	0	88,626
173	Durango	23	9	0	35,150
174	Erie	18	9	0	32,829
175	Windsor	17	9	0	23,500
176	Niwot	20	9	0	21,452
177	Montrose	17	9	0	19,305
178	Johnstown	17	9	0	18,882
179	Monument	24	9	0	17,694
180	Evergreen	15	9	0	15,750
181	Frederick	13	9	0	15,727
182	Dolores	18	9	0	13,797
183	Telluride	14	9	0	7,900
184	Hayden	16	9	0	3,915
185	Cripple Creek	15	9	0	2,817
186	Cedaredge	12	9	0	2,700
187	Crested Butte	13	9	0	2,440
188	Strasburg	13	9	0	2,050
189	Eads	13	9	0	622
190	Victor	14	9	0	491
191	Beulah	15	9	0	445
192	Empire	19	9	0	443
193	Ridgway	12	9	0	261
194	Ouray	18	9	0	200
195	Eastlake	13	9	0	200
196	Fort Smith	13	9	0	80
197	St Louis	12	9	0	70
198	Lake City	14	9	0	67
199	Silverton	12	9	0	0
200	Agate	16	9	0	0
201	Austin	10	9	0	0
202	Manitou Springs	13	9	0	0
203	Sedgwick	10	9	0	0
204	Boulder	20	8	0	166,080
205	Longmont	14	8	0	101,754
206	Glenwood Springs	13	8	0	9,428
207	Winter Park	13	8	0	6,635
208	Lyons	14	8	0	3,597
209	Hudson	12	8	0	3,350
210	Rangely	14	8	0	2,320
211	Lasalle	9	8	0	2,010
212	El Jebel	12	8	0	1,962
213	Norwood	12	8	0	1,700
214	Olathe	11	8	0	1,700
215	Wiley	15	8	1	1,500
216	Gilcrest	9	8	0	1,150
217	Oak Creek	12	8	0	950
218	Fairplay	10	8	0	909
219	Los Angeles	20	8	0	750
220	Saguache	12	8	0	485
221	Red Cliff	11	8	0	451
222	Lamar	14	8	0	378
223	Allenspark	10	8	0	340
224	Seibert	13	8	0	296
225	Redstone	12	8	0	180
226	Chino Hills	10	8	0	135
227	Buffalo Creek	14	8	0	125
228	Garcia	10	8	0	100
229	San Francisco	13	8	0	91
230	Raymer	11	8	0	73
231	Chromo	13	8	0	0
232	Alma	12	8	0	0
233	Springfield	18	8	0	0
234	Iliff	11	8	0	0
235	Stratton	12	8	0	0
236	Kremmling	12	8	0	0
237	Snowmass Village	11	8	0	0
238	Flagler	13	8	0	0
239	Limon	15	8	0	0
240	Briggsdale	12	8	0	0
241	Delta	14	8	0	0
242	Naturita	13	8	0	0
243	Craig	17	7	0	9,901
244	Idaho Springs	12	7	0	9,390
245	Mount Crested Butte	11	7	0	3,296
246	Platteville	8	7	0	2,900
247	Nederland	10	7	0	2,406
248	Wray	12	7	0	2,342
249	Kersey	9	7	0	2,101
250	Ignacio	8	7	0	800
251	Cortez	7	7	0	490
252	Romeo	11	7	0	450
253	Snowmass	9	7	0	322
254	Jamestown	9	7	0	280
255	Henderson	7	7	0	261
256	Sheridan Lake	13	7	1	148
257	Salida	10	7	0	100
258	Dumont	13	7	0	67
259	Placerville	11	7	0	59
260	Campo	10	7	0	0
261	Yampa	13	7	0	0
262	Dove Creek	12	7	0	0
263	Dacono	8	7	0	0
264	Crook	13	7	0	0
265	Georgetown	11	7	0	0
266	Firestone	8	6	0	17,792
267	Fort Lupton	10	6	0	15,465
268	Central City	9	6	0	3,750
269	Bennett	14	6	0	3,100
270	Mancos	10	6	0	1,390
271	Rye	12	6	2	745
272	Gateway	8	6	0	370
273	La Veta	8	6	0	300
274	Elbert	10	6	0	300
275	Nathrop	8	6	0	250
276	Hasty	11	6	1	244
277	Santa Ana	10	6	0	200
278	Ophir	10	6	0	193
279	Almont	10	6	0	113
280	Creede	11	6	0	0
281	Arapahoe	10	6	0	0
282	Silver Cliff	11	6	0	0
283	Pritchett	9	6	0	0
284	Holyoke	11	5	0	2,540
285	Haxtun	10	5	0	952
286	Bloomfield Hills	8	5	0	440
287	Mcclave	12	5	0	440
288	Crestone	6	5	0	293
289	Sedalia	7	5	0	35
290	Nucla	9	5	0	0
291	Eckley	9	5	0	0
292	Seminole	7	5	0	0
293	Bethune	8	5	0	0
294	Pueblo	14	4	0	113,480
295	Las Animas	5	4	0	2,410
296	Sanford	5	4	0	850
297	Calhan	6	4	0	780
298	Larkspur	5	4	0	275
299	Sugar City	8	4	0	240
300	Stockton	7	4	0	150
301	Paoli	8	4	0	42
302	Paradox	6	4	0	0
303	Granada	4	4	0	0
304	Manassa	5	4	0	0
305	Capulin	5	4	0	0
306	Ft Garland	7	4	0	0
307	Center	6	4	0	0
308	Alamosa	8	3	0	11,271
309	San Luis	4	3	0	629
310	Los Altos	5	3	0	215
311	Northbrook	4	3	0	105
312	Cheyenne	9	3	0	42
313	Rico	6	3	0	0
314	Monte Vista	4	3	0	0
315	Dinosaur	6	3	0	0
316	La Jara	4	3	0	0
317	Fleming	7	3	0	0
318	Blanca	6	3	0	0
319	Manzanola	2	2	1	270
320	Cheraw	5	2	1	154
321	Crawford	2	1	0	499
322	Administrative Contact	6	1	0	460
323	Ward	3	1	0	230
324	Hartman	1	1	0	93
325	Brandon	7	1	0	25
326	Ramah	3	1	0	0
327	Pine	1	0	0	232

Recommended Filtration for Colorado

Based on the most common contaminants found across Colorado (Total trihalomethanes (TTHMs), Bromodichloromethane, Haloacetic acids (HAA5)), we recommend a reverse osmosis system or high-quality carbon block filter to remove disinfection byproducts and their precursors.

Echo RO System

Removes up to 99.9% of contaminants. The gold standard for drinking water in Colorado homes.

View RO Systems

Echo Whole-Home Filter

Protect every tap in your home from chlorine, VOCs, and disinfection byproducts.

View Whole-Home Filters

Echo Hydrogen Water Flask

Once your water is clean, supercharge it with molecular hydrogen for antioxidant and anti-inflammatory benefits.

Shop Hydrogen Flask

Frequently Asked Questions

Is Colorado tap water safe to drink?

Water quality varies significantly across Colorado. Of the 327 cities analyzed, the average city has 9.4 contaminants above EWG health guidelines. The best water quality was found in Pine. We recommend checking your specific city's report for detailed information.

What city has the best water in Colorado?

Based on our analysis, Pine has the fewest contaminants above EWG health guidelines in Colorado, with 0 above guideline levels.

What city has the worst water in Colorado?

Based on our analysis, Thornton has the most contaminants above EWG health guidelines in Colorado, with 22 above guideline levels.

What's the best water filter for Colorado residents?

For most Colorado households, we recommend a reverse osmosis (RO) system for drinking water and a whole-home filter for showers and baths. The specific recommendation depends on your city's contaminant profile — check your city's report for personalized guidance.

National Water Quality Reports

Data sources: Environmental Working Group (EWG) Tap Water Database, U.S. EPA Safe Drinking Water Information System (SDWIS)

Last updated: March 2026

Methodology: Contaminant levels are compared against both EPA legal limits (Maximum Contaminant Levels) and EWG health guidelines, which are often stricter and based on the latest scientific research.

Colorado Water Quality Report (2026)