Colorado tap water quality
1,061 active community water systems.
Largest water systems
| Grade | System | People | Health violations (5y) |
|---|
| B | Denver Water | 1,287,000 | 0 |
| A | City of Aurora Water | 533,407 | 0 |
| A | Colorado Springs Utilities | 464,111 | 0 |
| B | City of Thornton | 226,465 | 0 |
| A | City of Westminster | 202,078 | 0 |
| B | City of Ft Collins | 179,901 | 0 |
| A | City of Arvada | 171,610 | 0 |
| A | City of Boulder | 166,080 | 0 |
| A | City of Greeley | 132,310 | 0 |
| A | Pueblo Board of WW | 114,070 | 0 |
| B | Town of Castle Rock | 110,298 | 0 |
| B | Broomfield City and County of | 106,153 | 1 |
| A | City of Longmont | 104,178 | 0 |
| A | Highlands Ranch WSD | 103,444 | 0 |
| A | Ute Wcd | 92,580 | 0 |
| A | City of Loveland | 91,077 | 0 |
| A | Consolidated Mutual Maple Grove | 81,400 | 0 |
| B | Parker WSD | 75,949 | 0 |
| A | South Adams County WSD | 75,559 | 0 |
| A | East Cherry Creek Valley WSD | 66,130 | 0 |
| A | Ft Collins Loveland WD | 63,532 | 0 |
| A | City of Englewood | 59,904 | 0 |
| C | City of Brighton | 56,304 | 1 |
| A | Southgate WSD | 55,000 | 0 |
| A | Eagle River WSD | 51,515 | 0 |
| A | Green Mountain WSD | 49,400 | 0 |
| A | City of Northglenn | 48,927 | 0 |
| A | Southwest Metropolitan WSD | 48,648 | 0 |
| A | Us Department of the Army Fort Carson | 48,000 | 0 |
| A | Town of Erie | 47,444 | 0 |
| A | Bancroft Clover WSD | 44,000 | 0 |
| A | City of Golden | 38,288 | 0 |
| A | City of Canon City | 34,800 | 0 |
| A | Clifton WD | 34,500 | 0 |
| A | City of Durango | 33,787 | 0 |
| B | City of Aspen | 31,100 | 0 |
| A | Arapahoe Cnty Wwwa | 31,000 | 0 |
| A | Bear Creek WSD | 30,000 | 0 |
| C | Pueblo West Md | 30,000 | 1 |
| A | Cherokee Md | 29,610 | 0 |
| B | City of Lafayette | 28,700 | 0 |
| C | Town of Breckenridge | 28,315 | 2 |
| B | East Larimer County WD | 27,944 | 0 |
| A | Town of Firestone | 27,798 | 0 |
| D | Widefield WSD | 27,640 | 0 |
| B | Csu Main and West Housing Campus | 27,375 | 0 |
| A | Town of Johnstown | 27,295 | 0 |
| A | City of Grand Junction | 26,000 | 0 |
| A | Little Thompson WD | 25,654 | 0 |
| A | City of Fountain | 25,130 | 0 |
Most issues (systems serving 10,000+)
DNo health-based violations in the last 5 years; 7 monitoring/reporting violations; PFOA/PFOS average above the 4 ppt federal limit: PFOA, PFOS; Other PFAS above 2024 limits (rule proposed for repeal): PFHxS, Hazard Index; Lead 90th percentile below the action level (2025).
D3 health-based violations in the last 5 years; 35 monitoring/reporting violations; 1 not yet resolved; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
C2 health-based violations in the last 5 years; 13 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
C2 health-based violations in the last 5 years; 15 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2026).
C2 health-based violations in the last 5 years; 5 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2026).
C1 health-based violation in the last 5 years; PFOA/PFOS average above the 4 ppt federal limit: PFOS; Lead 90th percentile below the action level (2023).
C2 health-based violations in the last 5 years; 1 monitoring/reporting violation; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
C1 health-based violation in the last 5 years; 19 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
B1 health-based violation in the last 5 years; 3 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
B1 health-based violation in the last 5 years; 1 monitoring/reporting violation; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2024).
BNo health-based violations in the last 5 years; 34 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2026).
B1 health-based violation in the last 5 years; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
BNo health-based violations in the last 5 years; 14 monitoring/reporting violations; 1 not yet resolved; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
BNo health-based violations in the last 5 years; 9 monitoring/reporting violations; 1 not yet resolved; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
BNo health-based violations in the last 5 years; 9 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
BNo health-based violations in the last 5 years; 9 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2026).
BNo health-based violations in the last 5 years; 8 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2026).
BNo health-based violations in the last 5 years; 8 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
BNo health-based violations in the last 5 years; 7 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2025).
BNo health-based violations in the last 5 years; 7 monitoring/reporting violations; PFAS tested (UCMR 5), none above federal limits; Lead 90th percentile below the action level (2023).
Cities
AgateAkronAlamosaAllensparkAlmaAntonitoArapahoeArbolesArribaArvadaAspenAtwoodAultAuroraAustinAvonAvondaleBaileyBasaltBattlement MesaBayfieldBellvueBennettBerthoudBethuneBeulahBlack HawkBlancaBoncarboBooneBoulderBransonBreckenridgeBriggsdaleBrightonBroomfieldBrushBuena VistaBurlingtonCahoneCalhanCampoCanon CityCarbondaleCarrCascadeCastle RockCedaredgeCenterCentral CityCherawCheyenne WellsChromoCimarronClarkCliftonCoal CreekColorado CityColorado SpringsCommerce CityComoConejosConiferCortezCraigCrawfordCreedeCrested ButteCrestoneCripple CreekCrookCrowleyDaconoDeer TrailDel NorteDeltaDenverDillonDinosaurDivideDoloresDove CreekDumontDupontDurangoEadsEagleEatonEckleyEdwardsElbertEldorado SpringsElizabethEnglewoodErieEstes ParkEvansEvergreenFairplayFirestoneFlaglerFlemingFlorenceFlorissantFort CollinsFort GarlandFort LuptonFort Lupton (Lupton)Fort LyonFort MorganFountainFranktownFrederickFriscoFruitaGaletonGardnerGatewayGenoaGilcrestGillGlendaleGlenwood SpringsGoldenGranbyGrand JunctionGrand LakeGreeleyGreen Mountain FallsGroverGunnisonGypsumHamiltonHartmanHartselHaswellHaxtunHaydenHendersonHesperusHillroseHollyHolyokeHot Sulphur SpringsHotchkissHowardHudsonHugoIdaho SpringsIdaliaIdledaleIgnacioIliffIndian HillsJamestownJarosoJohnstownJulesburgKarvalKeenesburgKerseyKimKiowaKit CarsonKittredgeKremmlingLa JaraLa JuntaLa SalleLa VetaLafayetteLake CityLake GeorgeLamarLaporteLarkspurLeadvilleLewisLimonLittletonLivermoreLog Lane VillageLomaLone TreeLongmontLouisvilleLouviersLovelandLucerneLyonsMackMancosManitou SpringsManzanolaMc ClaveMeadMeekerMesaMesa Verde National ParkMillikenMoffatMolinaMonte VistaMontroseMonumentMorrisonNathropNederlandNew CastleNew RaymerNiwotNorwoodNuclaNunnOak CreekOlatheOlney SpringsOphirOrchardOtisOurayOvidPagosa SpringsPalisadePalmer LakePaoliPaoniaParachuteParadoxParkerPeetzPenrosePeytonPhippsburgPiercePinePitkinPlacervillePlattevillePoncha SpringsPuebloRandRangelyRed CliffRed Feather LakesRedvaleRicoRidgwayRifleRockvaleRocky FordRomeoRyeSaguacheSalidaSan LuisSanfordSedaliaSedgwickSeibertSeveranceShawneeSheridan LakeSiltSilverthorneSilvertonSimlaSnowmassSnowmass VillageSnyderSomersetSouth ForkSpringfieldSteamboat SpringsSterlingStrasburgStrattonSugar CitySwinkTabernashTellurideThorntonTimnathTrinidadTwo ButtesUsaf AcademyVailVictorVilasVonaWaldenWalsenburgWalshWardWatkinsWeldonaWellingtonWestcliffeWestminsterWestonWetmoreWheat RidgeWhitewaterWigginsWileyWindsorWinter ParkWolcottWoodland ParkWoody CreekYampaYellow JacketYuma