Systems with a yearly average at or above an EPA-based study benchmark
2.9%4 of 136 active community water systems
All 136 systems had enough required samples to calculate a yearly average. 4 had at least one yearly average at or above a study benchmark; 132 did not.
EPA-based study benchmark: the unrounded cutoff this research uses to reproduce EPA’s January 2026 technical-assistance classification around the April 2024 federal levels. It is not a current standard or compliance finding and cannot determine household exposure or health risk.
Check your area
Find your water system
ZIP codes are used only to route visitors to public water systems that reported serving them. Confirm the actual provider using a water bill or utility record.
Compound summary
System counts in Colorado
Each count shows how many included water systems had a yearly average at or above the named study benchmark.
| Study benchmark | Systems at or above benchmark | Water systems included | Percent |
|---|---|---|---|
| PFOA: 4.05 ppt study benchmark (reproduces EPA classification around 4 ppt) | 1 | 136 | 0.7% |
| PFOS: 4.05 ppt study benchmark (reproduces EPA classification around 4 ppt) | 4 | 136 | 2.9% |
| PFHxS: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 1 | 136 | 0.7% |
| PFNA: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 0 | 136 | 0.0% |
| HFPO-DA: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 0 | 136 | 0.0% |
| Hazard Index: 1.5 study benchmark with at least two detected components (reproduces EPA classification around 1) | 1 | 136 | 0.7% |
System directory
Community water systems with complete monitoring
“Complete monitoring” means at least one sampling location had all required samples needed for a yearly average. Each PWSID appears once, preventing double counting across ZIP associations.
| Public water system | PWSID | Population served | Primary source | Sampling locations | Study benchmark result |
|---|---|---|---|---|---|
| ADVENIR FRENCH QUARTER | CO0116104 | 3,447 | Surface water purchased | 1 | Below all study benchmarks |
| ALAMOSA CITY OF | CO0102100 | 11,271 | Ground water | 1 | Below all study benchmarks |
| ANTONITO TOWN OF | CO0111100 | 981 | Groundwater under influence of surface water | 1 | Below all study benchmarks |
| ARAPAHOE CNTY WWWA | CO0203002 | 31,000 | Ground water | 7 | Below all study benchmarks |
| ARVADA CITY OF | CO0130001 | 171,610 | Surface water | 2 | Below all study benchmarks |
| ASPEN CITY OF | CO0149122 | 31,100 | Surface water | 1 | Below all study benchmarks |
| AURORA CITY OF | CO0103005 | 533,407 | Surface water | 3 | Below all study benchmarks |
| BERTHOUD TOWN OF | CO0135138 | 14,211 | Surface water | 1 | Below all study benchmarks |
| BLACK HAWK CITY OF | CO0124147 | 15,167 | Surface water | 2 | Below all study benchmarks |
| BOULDER CITY OF | CO0107152 | 166,080 | Surface water | 2 | Below all study benchmarks |
| BRECKENRIDGE TOWN OF | CO0159020 | 28,315 | Surface water | 1 | Below all study benchmarks |
| BRIGHTON CITY OF | CO0101025 | 56,304 | Surface water purchased | 4 | At or above a study benchmark |
| BROOMFIELD CITY AND COUNTY OF | CO0107155 | 106,153 | Surface water | 1 | Below all study benchmarks |
| BUENA VISTA TOWN OF | CO0108300 | 3,776 | Groundwater under influence of surface water | 2 | Below all study benchmarks |
| BURLINGTON CITY OF | CO0132005 | 3,720 | Ground water | 2 | Below all study benchmarks |
| CANON CITY CITY OF | CO0122100 | 34,800 | Surface water | 1 | Below all study benchmarks |
| CASTLE PINES VILLAGE MD | CO0118005 | 5,656 | Ground water | 2 | Below all study benchmarks |
| CASTLE ROCK TOWN OF | CO0118010 | 110,298 | Surface water | 5 | Below all study benchmarks |
| CENTENNIAL WSD | CO0118015 | 103,444 | Surface water | 3 | Below all study benchmarks |
| CENTRAL CITY CITY OF | CO0124171 | 3,750 | Surface water | 1 | Below all study benchmarks |
| CHEROKEE MD | CO0121125 | 29,610 | Ground water | 3 | Below all study benchmarks |
| CHIPETA WD | CO0143176 | 3,802 | Surface water purchased | 1 | Below all study benchmarks |
| CLIFTON WD | CO0139180 | 34,500 | Surface water | 1 | Below all study benchmarks |
| COLORADO SPRINGS UTILITIES | CO0121150 | 464,111 | Surface water | 6 | Below all study benchmarks |
| CONSOLIDATED MUTUAL MAPLE GROVE | CO0130020 | 81,400 | Surface water | 1 | Below all study benchmarks |
| COPPER MOUNTAIN CONSOLIDATED MD | CO0159030 | 5,785 | Ground water | 2 | Below all study benchmarks |
| COTTONWOOD WSD | CO0118020 | 10,867 | Surface water purchased | 2 | Below all study benchmarks |
| CRAIG CITY OF | CO0141188 | 8,930 | Surface water | 1 | Below all study benchmarks |
| CRAWFORD MESA WA | CO0115189 | 486 | Ground water | 1 | Below all study benchmarks |
| CREEDE CITY OF | CO0140500 | 1,965 | Ground water | 1 | Below all study benchmarks |
| DACONO CITY OF | CO0162200 | 6,900 | Surface water purchased | 1 | Below all study benchmarks |
| DELTA CITY OF | CO0115205 | 8,700 | Surface water purchased | 1 | Below all study benchmarks |
| DENVER WATER BOARD | CO0116001 | 1,287,000 | Surface water | 4 | Below all study benchmarks |
| DOLORES TOWN OF | CO0142400 | 1,626 | Surface water | 1 | Below all study benchmarks |
| DONALA WSD | CO0121175 | 6,421 | Surface water purchased | 3 | Below all study benchmarks |
| DURANGO CITY OF | CO0134150 | 33,787 | Surface water | 1 | Below all study benchmarks |
| EAGLE RIVER WSD | CO0119802 | 51,515 | Surface water | 11 | Below all study benchmarks |
| EAGLE TOWN OF | CO0119233 | 7,511 | Surface water | 2 | Below all study benchmarks |
| EAST CHERRY CREEK VALLEY WSD | CO0103035 | 66,130 | Surface water purchased | 4 | Below all study benchmarks |
| EAST LARIMER COUNTY WD | CO0135233 | 27,944 | Surface water purchased | 1 | Below all study benchmarks |
| ENGLEWOOD CITY OF | CO0103045 | 57,332 | Surface water | 1 | Below all study benchmarks |
| ERIE TOWN OF | CO0162255 | 47,444 | Surface water | 1 | Below all study benchmarks |
| ESTES PARK TOWN OF | CO0135257 | 16,722 | Surface water | 2 | Below all study benchmarks |
| EVANS CITY OF | CO0162260 | 19,369 | Surface water purchased | 1 | Below all study benchmarks |
| EVERGREEN MD | CO0130030 | 15,750 | Surface water | 1 | Below all study benchmarks |
| FEDERAL HEIGHTS CITY OF | CO0101055 | 11,678 | Surface water purchased | 2 | Below all study benchmarks |
| FIRESTONE TOWN OF | CO0162476 | 27,798 | Surface water purchased | 1 | Below all study benchmarks |
| FOUNTAIN CITY OF | CO0121275 | 25,130 | Surface water purchased | 4 | Below all study benchmarks |
| FRISCO TOWN OF | CO0159055 | 4,495 | Surface water | 3 | Below all study benchmarks |
| FT COLLINS CITY OF | CO0135291 | 179,901 | Surface water | 1 | Below all study benchmarks |
| FT COLLINS LOVELAND WD | CO0135292 | 63,532 | Surface water purchased | 2 | Below all study benchmarks |
| FT LUPTON CITY OF | CO0162291 | 12,099 | Surface water | 1 | Below all study benchmarks |
| FT MORGAN CITY OF | CO0144005 | 12,000 | Surface water | 1 | Below all study benchmarks |
| GENESEE WSD | CO0130035 | 3,920 | Surface water | 1 | Below all study benchmarks |
| GLENWOOD SPRINGS CITY OF | CO0123314 | 9,428 | Surface water | 1 | Below all study benchmarks |
| GOLDEN CITY OF | CO0130040 | 38,288 | Surface water | 1 | Below all study benchmarks |
| GRAND COUNTY WATER NO 1 | CO0125323 | 5,400 | Surface water | 2 | Below all study benchmarks |
| GRAND JUNCTION CITY OF | CO0139321 | 26,000 | Surface water | 1 | Below all study benchmarks |
| GREELEY CITY OF | CO0162321 | 132,310 | Surface water | 2 | Below all study benchmarks |
| GUNNISON CITY OF | CO0126325 | 9,610 | Ground water | 9 | Below all study benchmarks |
| GYPSUM TOWN OF | CO0119329 | 15,272 | Surface water | 2 | Below all study benchmarks |
| HAYDEN TOWN OF | CO0154333 | 3,982 | Surface water | 1 | Below all study benchmarks |
| IDAHO SPRINGS CITY OF | CO0110020 | 10,432 | Surface water | 1 | Below all study benchmarks |
| INVERNESS WSD | CO0203012 | 8,140 | Surface water purchased | 6 | Below all study benchmarks |
| JOHNSTOWN TOWN OF | CO0162418 | 27,295 | Surface water | 1 | Below all study benchmarks |
| LA JUNTA CITY OF | CO0145420 | 8,320 | Ground water | 1 | Below all study benchmarks |
| LAFAYETTE CITY OF | CO0107473 | 28,700 | Surface water | 2 | Below all study benchmarks |
| LAMAR CITY OF | CO0150700 | 7,500 | Ground water | 1 | Below all study benchmarks |
| LEFT HAND WD | CO0107471 | 20,280 | Surface water | 2 | Below all study benchmarks |
| LIMON TOWN OF | CO0137015 | 5,080 | Ground water | 1 | Below all study benchmarks |
| LITTLE THOMPSON WD | CO0135477 | 25,654 | Surface water purchased | 1 | Below all study benchmarks |
| LOCHBUIE TOWN OF | CO0162486 | 6,518 | Ground water | 1 | Below all study benchmarks |
| LONGMONT CITY OF | CO0107485 | 104,178 | Surface water | 1 | Below all study benchmarks |
| LOUISVILLE CITY OF | CO0107487 | 20,975 | Surface water | 2 | Below all study benchmarks |
| LOVELAND CITY OF | CO0135485 | 91,077 | Surface water | 2 | Below all study benchmarks |
| MANITOU SPRINGS CITY OF | CO0121450 | 6,938 | Surface water | 1 | Below all study benchmarks |
| MENOKEN WD | CO0143506 | 4,500 | Surface water purchased | 1 | Below all study benchmarks |
| MERIDIAN MD | CO0218015 | 23,415 | Surface water purchased | 3 | Below all study benchmarks |
| MERIDIAN SERVICE MD | CO0121455 | 12,760 | Ground water | 1 | Below all study benchmarks |
| MID VALLEY MD | CO0119508 | 4,588 | Ground water | 3 | Below all study benchmarks |
| MONTE VISTA CITY OF | CO0153600 | 4,600 | Ground water | 3 | Below all study benchmarks |
| MONTEZUMA WC | CO0142900 | 13,797 | Surface water | 1 | Below all study benchmarks |
| MONTROSE CITY OF | CO0143518 | 19,305 | Surface water purchased | 1 | Below all study benchmarks |
| MONUMENT TOWN OF | CO0121475 | 5,740 | Ground water | 6 | Below all study benchmarks |
| MORGAN COUNTY QUALITY WD | CO0144020 | 8,116 | Surface water purchased | 3 | Below all study benchmarks |
| MORRISON TOWN OF | CO0130085 | 9,887 | Surface water | 1 | Below all study benchmarks |
| MOUNTAIN VILLAGE TOWN OF | CO0157400 | 9,700 | Ground water | 4 | Below all study benchmarks |
| MT WERNER WD | CO0154524 | 19,000 | Surface water | 2 | Below all study benchmarks |
| NEW CASTLE TOWN OF | CO0123538 | 5,024 | Surface water | 1 | Below all study benchmarks |
| NORTH TABLE MOUNTAIN WSD | CO0130105 | 10,000 | Surface water | 1 | Below all study benchmarks |
| NORTH WELD COUNTY WD | CO0162553 | 15,890 | Surface water purchased | 2 | Below all study benchmarks |
| NORTHERN COLORADO WA | CO0135554 | 4,675 | Surface water purchased | 3 | Below all study benchmarks |
| NORTHERN DOUGLAS COUNTY WSD | CO0118016 | 6,160 | Surface water purchased | 1 | Below all study benchmarks |
| NORTHGLENN CITY OF | CO0101115 | 48,927 | Surface water | 1 | Below all study benchmarks |
| PAGOSA AREA WSD | CO0104300 | 11,069 | Surface water | 3 | Below all study benchmarks |
| PAINT BRUSH HILLS | CO0221690 | 4,994 | Ground water | 2 | Below all study benchmarks |
| PARK CENTER WD | CO0122600 | 4,000 | Surface water | 1 | Below all study benchmarks |
| PARKER WSD | CO0118040 | 75,949 | Surface water | 11 | Below all study benchmarks |
| PARKVILLE WD | CO0133700 | 7,500 | Surface water | 2 | Below all study benchmarks |
| PATTERSON VALLEY WC | CO0145540 | 96 | Ground water | 1 | Below all study benchmarks |
| PERRY PARK WSD | CO0118045 | 3,890 | Groundwater under influence of surface water | 3 | Below all study benchmarks |
| PINERY WWD | CO0118025 | 12,901 | Surface water purchased | 6 | Below all study benchmarks |
| PUEBLO BOARD OF WW | CO0151500 | 114,070 | Surface water | 1 | Below all study benchmarks |
| PUEBLO WEST MD | CO0151650 | 30,000 | Surface water | 3 | Below all study benchmarks |
| RIFLE CITY OF | CO0123676 | 9,489 | Surface water | 1 | Below all study benchmarks |
| ROCKY FORD CITY OF | CO0145600 | 4,443 | Ground water | 1 | Below all study benchmarks |
| ROXBOROUGH WSD | CO0118055 | 13,765 | Surface water | 1 | Below all study benchmarks |
| SALIDA CITY OF | CO0108700 | 5,666 | Surface water | 3 | Below all study benchmarks |
| SECURITY WSD | CO0121775 | 20,000 | Surface water purchased | 3 | Below all study benchmarks |
| SILVERTHORNE TOWN OF | CO0159095 | 8,400 | Ground water | 4 | Below all study benchmarks |
| SNAKE RIVER WD | CO0159105 | 9,900 | Ground water | 2 | At or above a study benchmark |
| SNOWMASS VILLAGE WSD | CO0149717 | 6,353 | Surface water | 1 | Below all study benchmarks |
| SOUTH ADAMS COUNTY WSD | CO0101140 | 75,559 | Surface water purchased | 5 | Below all study benchmarks |
| STEAMBOAT SPRINGS CITY OF | CO0154725 | 9,950 | Surface water purchased | 1 | Below all study benchmarks |
| STERLING CITY OF | CO0138045 | 15,100 | Groundwater under influence of surface water | 1 | Below all study benchmarks |
| STONEGATE MD | CO0118076 | 15,295 | Surface water purchased | 1 | Below all study benchmarks |
| SUPERIOR MD NO 1 | CO0107725 | 17,900 | Surface water | 1 | Below all study benchmarks |
| TELLURIDE TOWN OF | CO0157800 | 7,900 | Surface water | 2 | Below all study benchmarks |
| THORNTON CITY OF | CO0101150 | 226,465 | Surface water | 2 | Below all study benchmarks |
| TODD CREEK VILLAGE MD | CO0101157 | 7,363 | Groundwater under influence of surface water | 1 | At or above a study benchmark |
| TRI COUNTY WCD | CO0143755 | 20,490 | Surface water purchased | 1 | Below all study benchmarks |
| TRINIDAD CITY OF | CO0136800 | 11,400 | Surface water | 1 | Below all study benchmarks |
| TWO RIVERS VILLAGE | CO0119720 | 896 | Ground water | 1 | Below all study benchmarks |
| US AIR FORCE ACADEMY | CO0121845 | 16,876 | Surface water purchased | 1 | Below all study benchmarks |
| US DEPARTMENT OF THE ARMY FORT CARSON | CO0221445 | 48,000 | Surface water purchased | 1 | Below all study benchmarks |
| UTE WCD | CO0139791 | 92,580 | Surface water | 1 | Below all study benchmarks |
| WELLINGTON TOWN OF | CO0135838 | 11,720 | Surface water | 2 | Below all study benchmarks |
| WEST FORT COLLINS WD | CO0135290 | 4,000 | Surface water purchased | 1 | Below all study benchmarks |
| WESTMINSTER CITY OF | CO0101170 | 202,078 | Surface water | 2 | Below all study benchmarks |
| WIDEFIELD WSD | CO0121900 | 27,640 | Surface water purchased | 9 | At or above a study benchmark |
| WINDSOR TOWN OF | CO0162843 | 23,500 | Surface water purchased | 3 | Below all study benchmarks |
| WOODMEN HILLS MD | CO0121930 | 13,888 | Ground water | 3 | Below all study benchmarks |
| WOODMOOR WSD | CO0121950 | 18,031 | Surface water | 5 | Below all study benchmarks |
| YMCA ROCKIES WIND RIVER | CO0135883 | 3,730 | Surface water purchased | 1 | Below all study benchmarks |
| YMCA SNOW MTN RANCH | CO0125916 | 578 | Groundwater under influence of surface water | 1 | Below all study benchmarks |
| YUMA CITY OF | CO0163020 | 4,049 | Ground water | 6 | Below all study benchmarks |
How the count works
What is included
Each active community water system with enough required samples for a yearly average is counted once, even if it is linked with several ZIP codes. This does not mean every home was tested. Private wells are excluded, and UCMR 5 did not comprehensively monitor every small system. This page does not apply Colorado's state-specific standards or determine compliance. Use the official state or territory drinking-water program for current regulatory information.