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CheckYourWater

PFAS Testing Results

Colorado

PFAS testing results for 165 water systems serving 6,356,691 residents.

Systems tested

165

23.0% had PFAS detections

Limits exceeded

13

7.9% of systems

Population affected

529K

served by systems over federal limits

Most common compound

11Cl-PF3OUdS

detected in 35 systems

Grade distribution

Every water system gets a letter grade based on how its worst detected PFAS compound compares to the federal Maximum Contaminant Level. Lower grades mean higher contamination.

A — 127 systems (77.0%)
B — 13 systems (7.9%)
C — 12 systems (7.3%)
D — 13 systems (7.9%)
F — 0 systems (0.0%)

How grades are calculated →

Communities exceeding federal limits

The water systems in Colorado where at least one PFAS compound exceeds the EPA Maximum Contaminant Level, sorted worst first.

System nameCityGradeWorst compoundTimes over limitPopulation
SNAKE RIVER WDKEYSTONE
PFOS4.4x9.9K
WIDEFIELD WSDCOLORADO SPRINGS
PFOS2.5x28K
BRIGHTON CITY OFBRIGHTON
PFOS2.0x56K
MOUNTAIN VILLAGE TOWN OFREDVALE
PFOS1.9x9.7K
THORNTON CITY OFTHORNTON
PFOA1.7x226K
STONEGATE MDPARKER
PFOA1.4x15K
TODD CREEK VILLAGE MDBRIGHTON
PFOS1.3x7.2K
CHEROKEE MDCOLORADO SPRINGS
PFOA1.3x30K
LITTLE THOMPSON WDBERTHOUD
PFOA1.2x26K
PARKER WSDPARKER
PFOA1.2x76K

Resources for taking action are available in our community toolkit.

What Colorado is doing about PFAS

Colorado has enacted some of the more active PFAS legislation in the Mountain West. HB21-1189, signed in 2021, prohibits the use of fluorinated firefighting foam at oil and gas facilities and restricted AFFF use at state training sites. HB22-1345, signed in 2022, banned the sale of PFAS in several product categories including carpets, fabric treatments, cosmetics, and food packaging, with staggered effective dates running through 2027.

State records show the Colorado Department of Public Health and Environment has maintained a PFAS Action Plan and operates a sampling program focused on public water systems near known contamination sources, including Peterson Space Force Base and the Suncor refinery area north of Denver. The Water Quality Control Division has used Policy 20-1 as a state-level guidance value for site investigation cleanups, though it is not an enforceable drinking water MCL.

Litigation has been ongoing, with the Colorado Attorney General joining multistate actions against 3M and DuPont. Public water systems are subject to the federal compliance timeline requiring initial monitoring by 2027 and treatment installation by 2029.

Based on Colorado Department of Public Health and Environment publications and Colorado legislative records.

All 165 tested water systems in Colorado

Sorted from lowest grade to highest. Click any system name for the full report. Filter by city or name with the search box below.

Showing 50 of 165 systems

GradeSystem nameCityWorst compoundvs. EPA limitPopulation
SNAKE RIVER WDKEYSTONEPFOS4.4× the federal limit9.9K
WIDEFIELD WSDCOLORADO SPRINGSPFOS2.5× the federal limit28K
BRIGHTON CITY OFBRIGHTONPFOS2.0× the federal limit56K
MOUNTAIN VILLAGE TOWN OFREDVALEPFOS1.9× the federal limit9.7K
THORNTON CITY OFTHORNTONPFOA1.7× the federal limit226K
STONEGATE MDPARKERPFOA1.4× the federal limit15K
TODD CREEK VILLAGE MDBRIGHTONPFOS1.3× the federal limit7.2K
CHEROKEE MDCOLORADO SPRINGSPFOA1.3× the federal limit30K
LITTLE THOMPSON WDBERTHOUDPFOA1.2× the federal limit26K
PARKER WSDPARKERPFOA1.2× the federal limit76K
ARAPAHOE CNTY WWWACENTENNIALPFOA1.1× the federal limit31K
GUNNISON CITY OFGUNNISONPFOS1.1× the federal limit9.6K
ROCKY FORD CITY OFROCKY FORDPFOS1.0× the federal limit4.4K
ENGLEWOOD CITY OFENGLEWOODPFOA1.0× the federal limit57K
COTTONWOOD WSDENGLEWOODPFOA1.0× the federal limit11K
SOUTH ADAMS COUNTY WSDCOMMERCE CITYPFPeABelow detection74K
AURORA CITY OFAURORAPFBABelow detection533K
CASTLE PINES NORTH MDCASTLE PINESPFBABelow detection13K
CENTENNIAL WSDHIGHLANDS RANCHPFBABelow detection103K
NORTHERN DOUGLAS COUNTY WSDGREENWOOD VILLAGEPFBABelow detection6.2K
PINERY WWDPARKERPFPeABelow detection13K
FOUNTAIN CITY OFFOUNTAINPFPeABelow detection25K
SECURITY WSDCOLORADO SPRINGSPFPeABelow detection20K
STRATMOOR HILLS WSDCOLORADO SPRINGSPFHxABelow detection6.5K
CONSOLIDATED MUTUAL MAPLE GROVELAKEWOODPFBSBelow detection81K
SILVERTHORNE TOWN OFSILVERTHORNEPFHxSBelow federal limit8.4K
LAMAR CITY OFLAMARPFHxSBelow federal limit7.5K
LOCHBUIE TOWN OFLOCHBUIEPFHxSBelow federal limit6.8K
EAST CHERRY CREEK VALLEY WSDAURORAPFBABelow detection66K
DELTA CITY OFDELTAPFBABelow detection8.7K
CASTLE ROCK TOWN OFCASTLE ROCKPFBABelow detection107K
WOODMOOR WSDMONUMENTPFBSBelow detection18K
GRAND COUNTY WATER NO 1WINTER PARKPFBABelow detection5.4K
MORRISON TOWN OFMORRISONPFHxABelow detection9.9K
CHIPETA WDMONTROSEPFBABelow detection3.8K
SUBURBAN WATERMONTROSEPFBABelow detection859
INVERNESS WSDENGLEWOODPFBABelow detection8.1K
CSU FOOTHILLS CAMPUSFORT COLLINSPFBABelow detection4.5K
FEDERAL HEIGHTS CITY OFFEDERAL HEIGHTS-Below detection12K
NORTHGLENN CITY OFNORTHGLENN-Below detection49K
WESTMINSTER CITY OFWESTMINSTER-Below detection202K
ALAMOSA CITY OFALAMOSA-Below detection11K
PAGOSA AREA WSDPAGOSA SPRINGS-Below detection11K
NAVAJO RIVER RANCH POAPAGOSA SPRINGS-Below detection40
BOULDER CITY OFBOULDER-Below detection166K
BROOMFIELD CITY AND COUNTY OFBROOMFIELD-Below detection106K
LEFT HAND WDNIWOT-Below detection20K
LAFAYETTE CITY OFLAFAYETTE-Below detection29K
LONGMONT CITY OFLONGMONT-Below detection103K
LOUISVILLE CITY OFLOUISVILLE-Below detection21K

More on PFAS in Colorado

Investigations

City profiles

Check your water system

Enter your zip code to see the PFAS results for the water system that serves your home.

Where this data comes from

  • EPA Unregulated Contaminant Monitoring Rule, 5th cycle (UCMR 5)
  • Testing period: 2023 to 2026
  • Federal limits: EPA Maximum Contaminant Levels finalized April 2024
  • Read the full methodology