Why does water hardness vary across Colorado?

Water hardness varies across Colorado because utilities can use different groundwater wells, reservoirs, treatment plants, blends, and distribution zones. Private wells can also differ from nearby municipal water.

What city in Colorado has the hardest water?

Olney Springs has the hardest water among higher-confidence Colorado city pages at 1083 PPM. Check the city page for local systems and ZIP codes before making treatment decisions.

Does this include municipal water, well water, or both?

The state report combines public water system records, utility reports, and USGS monitoring where available. Municipal treated-water records are preferred when present. Private well hardness can vary at the address level and should be confirmed with a local test.

How many water systems are in Colorado?

Colorado has 1,048 active community water systems serving 386 cities.

Water Hardness in Colorado

Average: 299 PPMVery Hard386 cities1,048 water systems

State report

Is Colorado Water Hard or Soft?

Colorado water is very hard on average at 299 PPM (17.5 GPG). Local readings can vary by utility, aquifer, treatment plant, and private well use.

State average

299 PPM

Very Hard

Local coverage

386 cities

1,048 water systems

Source profile

383 ZIPs

direct or USGS-backed

80% of covered ZIPs use treated-water records or USGS monitoring, so the state report has relatively strong source support.

Methodology Data sources Search by ZIP code

State data profile

How to read the Colorado results

State pages are screening and comparison hubs. They summarize ZIP, city, and water-system patterns so you can find the local page that best matches your home or utility.

Direct or USGS-backed ZIPs

383 of 478

80% use treated-water records or USGS monitoring.

Estimated ZIP values

94 ZIPs

20% use nearby, county, or state-level fallback values.

Dataset update

March 9, 2026

Source coverage and rollups are rebuilt from the public dataset.

Use the source coverage below to judge how much local confirmation a specific city or ZIP needs. The methodology page explains the source hierarchy, weighting, and limitations.

State Average

299 PPM

Very Hard

Coverage

386 cities

1,048 water systems in the state rollup.

Data Source Coverage

ZIP-level source mix for Colorado; higher direct and USGS coverage means less reliance on regional estimates.

478 ZIPs covered

Verified treated water

Utility, CCR, or state treated-water records

47%

224 ZIPs

High-confidence USGS

Environmental monitoring matched to local systems

33%

159 ZIPs

Estimated

Nearby, county, or state-level fallback values

20%

94 ZIPs

1 ZIPs have insufficient source data and are excluded from search sitemaps.

In Colorado, 47% of ZIPs use verified treated-water records, 33% use high-confidence USGS monitoring, and 20% use estimates that should be confirmed locally for treatment decisions.

What the Data Shows in Colorado

Hard water is common but not universal in Colorado: 34% of classified ZIPs are hard or very hard.

Colorado uses a mixed data profile across treated-water records, USGS monitoring, and estimated fallback values.

Use the city table below to compare local results. For estimated locations or unusually high readings, confirm with your utility or a home hardness test before sizing treatment equipment.

ZIP Hardness Distribution

Soft8% (39)

Slightly Hard50% (239)

Moderately Hard8% (38)

Hard7% (34)

Very Hard27% (127)

Treatment Takeaway

Colorado has a mixed hardness profile. Some areas may benefit from softening, while others may only need point-of-use filtration or no hardness treatment at all.

How to Use This Data

The source coverage is relatively strong in Colorado, so these pages are useful for comparing local patterns before confirming your home's exact hardness.

Source-Backed Water Systems in Colorado

Large systems with treated-water reports or USGS monitoring behind the state rollup.

Review source labels

Water system	Hardness	Source label	Population
Denver Water Board CO0116001 - Denver County	90 PPM Slightly Hard	Annual Water Quality Report Verified - Annual Water Quality Report	1,287,000
Cherry Creek Valley Wsd CO0116175 - Denver County	90 PPM Slightly Hard	Annual Water Quality Report Verified - Annual Water Quality Report	22,000
Willowbrook Wsd CO0130843 - Jefferson County	90 PPM Slightly Hard	Annual Water Quality Report Verified - Annual Water Quality Report	9,348
Advenir French Quarter CO0116104 - Denver County	90 PPM Slightly Hard	Annual Water Quality Report Verified - Annual Water Quality Report	3,447
Meadowbrook Wd CO0130500 - Jefferson County	90 PPM Slightly Hard	Annual Water Quality Report Verified - Annual Water Quality Report	3,290
Eastern Adams Co Md CO0101234 - Adams County	90 PPM Slightly Hard	Annual Water Quality Report Verified - Annual Water Quality Report	2,485
North Lincoln Wsd CO0116552 - Jefferson County	90 PPM Slightly Hard	Annual Water Quality Report Verified - Annual Water Quality Report	1,000
Lamplighter Mobile Home Park CO0122467 - Fremont County	90 PPM Slightly Hard	Annual Water Quality Report Verified - Annual Water Quality Report	420

Useful Colorado City Pages

Shortcuts to city pages backed by more ZIP-code or water-system data.

Cities With More Local Data

Denver

24 ZIPs · 30 systems

Slightly Hard (90 PPM)

Colorado Springs

22 ZIPs · 47 systems

Slightly Hard (75 PPM)

Aurora

8 ZIPs · 30 systems

Slightly Hard (90 PPM)

Pueblo

6 ZIPs · 11 systems

Moderately Hard (120 PPM)

Littleton

5 ZIPs · 47 systems

Moderately Hard (134 PPM)

Fort Collins

5 ZIPs · 15 systems

Slightly Hard (80 PPM)

Prioritize cities with multiple ZIPs and systems, then use source badges on each city page to separate verified treated-water records from estimates.

Top 10 Hardest Water Cities

#	City	Hardness
1	Olney Springs	Very Hard (1083 PPM)
2	Rocky Ford	Very Hard (877 PPM)
3	Redvale	Very Hard (689 PPM)
4	Montrose	Very Hard (688 PPM)
5	Nucla	Very Hard (640 PPM)
6	Cortez	Very Hard (532 PPM)
7	Crawford	Very Hard (424 PPM)
8	Glenwood Springs	Very Hard (415 PPM)
9	De Beque	Very Hard (386 PPM)
10	Clifton	Very Hard (384 PPM)

Top 10 Softest Water Cities

#	City	Hardness
1	Grand Lake	Soft (22 PPM)
2	Pagosa Springs	Soft (39 PPM)
3	Paonia	Soft (42 PPM)
4	Aspen	Soft (44 PPM)
5	Elizabeth	Soft (57 PPM)
6	Granby	Soft (58 PPM)
7	Crested Butte	Slightly Hard (61 PPM)
8	Hotchkiss	Slightly Hard (74 PPM)
9	Steamboat Spring	Slightly Hard (74 PPM)
10	Calhan	Slightly Hard (75 PPM)

All Cities in Colorado

City pages marked Estimated use fallback values and should be confirmed with local testing or utility data.

AgateVery Hard AguilarEstimatedVery Hard AkronModerately Hard AlamosaSoft AllensparkSlightly Hard AlmaModerately Hard AlmontHard AmherstVery Hard AntonVery Hard AntonitoSoft ArapahoeHard ArbolesSoft ArlingtonSlightly Hard ArribaEstimatedVery Hard ArvadaSlightly Hard AspenSoft AtwoodVery Hard AultSlightly Hard AuroraSlightly Hard AustinVery Hard AvonHard BaileySlightly Hard BasaltHard Battlement MesaVery Hard BayfieldSlightly Hard BedrockVery Hard BellvueSlightly Hard BennettSlightly Hard BerthoudSlightly Hard BethuneModerately Hard BeulahModerately Hard Black HawkSoft BlancaSoft BoncarboEstimatedVery Hard BondHard BooneModerately Hard BoulderSlightly Hard Bow MarSlightly Hard BransonEstimatedVery Hard BreckenridgeSlightly Hard BriggsdaleSlightly Hard BroomfieldSlightly Hard BrushVery Hard Buena VistaSlightly Hard Buffalo CreekSlightly Hard BurlingtonModerately Hard BurnsHard ByersSlightly Hard CaddoaVery Hard CahoneVery Hard CalhanSlightly Hard CampoVery Hard Canon CityVery Hard CapulinSoft CarrSlightly Hard Castle RockHard CedaredgeSlightly Hard CentennialModerately Hard CenterHard Central CitySoft ChamaModerately Hard CherawVery Hard Cherry Hills VilSlightly Hard Cheyenne WellsHard ChivingtonVery Hard ChromoSoft CimarronSlightly Hard ClarkSlightly Hard CliftonVery Hard Coal CreekVery Hard CoaldaleVery Hard CoalmontSlightly Hard CollbranVery Hard Colorado SpringsSlightly Hard Commerce CitySlightly Hard ComoSlightly Hard ConiferSlightly Hard CopeVery Hard Copper MountainSlightly Hard CortezVery Hard CotopaxiVery Hard CowdreySlightly Hard CraigModerately Hard CrawfordVery Hard CreedeVery Hard Crested ButteSlightly Hard CrestoneModerately Hard Cripple CreekSlightly Hard CrookVery Hard CrowleySlightly Hard CucharaSoft DaconoSlightly Hard De BequeVery Hard DeckersHard Deer TrailSlightly Hard DelhiEstimatedVery Hard DeltaVery Hard DenverSlightly Hard DeoraVery Hard DinosaurVery Hard DivideSlightly Hard DoloresModerately Hard Dove CreekVery Hard DrakeSlightly Hard DumontSoft DupontSlightly Hard DurangoSlightly Hard EagleHard EatonSlightly Hard EckleyModerately Hard EdgewaterSlightly Hard EdwardsHard EgnarVery Hard ElbertSlightly Hard Eldorado SpringsSlightly Hard ElizabethSoft EmpireSoft EnglewoodSlightly Hard ErieSlightly Hard Estes ParkSlightly Hard EvansSlightly Hard EvergreenSlightly Hard FairplayModerately Hard FarisitaSlightly Hard FaristaVery Hard Federal HeightsSlightly Hard FirestoneSlightly Hard First InterstateSlightly Hard FlaglerHard FlemingVery Hard FlorenceVery Hard FlorissantSlightly Hard Fort CarsonSlightly Hard Fort CollinsSlightly Hard Fort GarlandSoft Fort MorganVery Hard FountainSlightly Hard FowlerVery Hard FranktownHard FraserSoft FrederickSlightly Hard FruitaVery Hard FruitvaleVery Hard Garden CitySlightly Hard GatewayVery Hard GenoaEstimatedVery Hard GeorgetownSoft GilcrestSlightly Hard GillSlightly Hard GilmanHard Glade ParkVery Hard Glen HavenSlightly Hard GlendaleSlightly Hard Glenwood SpringsVery Hard GoldenSlightly Hard GranadaHard GranbySoft Grand JunctionVery Hard Grand LakeSoft GrantSlightly Hard GreeleySlightly Hard Green Mountain FSlightly Hard Greenwood VillagSlightly Hard GroverSlightly Hard GuffeySlightly Hard GunnisonModerately Hard GypsumHard HaleVery Hard HamiltonVery Hard HartmanVery Hard HartselSlightly Hard HaswellVery Hard HaxtunVery Hard HaydenSlightly Hard HendersonSlightly Hard HesperusSlightly Hard Highlands RanchHard HillroseVery Hard HollyHard HolyokeVery Hard HooperSoft Hot Sulphur SpriSoft HotchkissSlightly Hard HowardVery Hard HoytVery Hard HudsonSlightly Hard HugoEstimatedVery Hard Idaho SpringsSoft IgnacioSlightly Hard IliffVery Hard Indian HillsSlightly Hard JamestownSlightly Hard JansenEstimatedVery Hard JeffersonSlightly Hard JoesVery Hard JohnstownSlightly Hard JulesburgVery Hard KarvalEstimatedVery Hard KeenesburgSlightly Hard KerseySlightly Hard KeystoneSlightly Hard KiowaSoft KirkVery Hard Kit CarsonVery Hard KittredgeSlightly Hard KremmlingVery Hard La GaritaModerately Hard La JaraSoft La SalleSlightly Hard LafayetteSlightly Hard LairdModerately Hard Lake CityVery Hard Lake GeorgeModerately Hard LakewoodSlightly Hard LamarHard LaporteSlightly Hard LarkspurHard Last ChanceSlightly Hard LeadvilleSlightly Hard LewisModerately Hard LimonEstimatedVery Hard Lincoln Center BSlightly Hard LindonSlightly Hard LittletonModerately Hard LochbuiSlightly Hard Log Lane VillageVery Hard LomaVery Hard LongmontSlightly Hard LouisvilleSlightly Hard LovelandSlightly Hard Lowry AfbSlightly Hard LycanHard LyonsSlightly Hard MackVery Hard ManassaSoft MancosModerately Hard Manitou SpringsSlightly Hard ManzanolaVery Hard MarbleVery Hard MathesonSlightly Hard MaybellVery Hard Mc ClaveVery Hard Mc CoyHard MeadSlightly Hard MeekerHard MeredithSoft MesaVery Hard Mesa Verde NatioModerately Hard MesitaSoft MillikenSlightly Hard MoffatSlightly Hard MolinaVery Hard Monte VistaSlightly Hard MontroseVery Hard MonumentSlightly Hard MorrisonSlightly Hard MoscaSoft Mountain ViewSlightly Hard NathropModerately Hard NaturitaVery Hard NederlandSlightly Hard New CastleVery Hard New RaymerSlightly Hard North AvondaleModerately Hard North PoleSlightly Hard NorthglennSlightly Hard NorwoodVery Hard NuclaVery Hard NunnSlightly Hard Oak CreekSlightly Hard OlatheVery Hard Olney SpringsVery Hard OphirModerately Hard OrchardVery Hard OrdwayVery Hard OtisModerately Hard OurayVery Hard OvidVery Hard PadroniVery Hard Pagosa SpringsSoft PalisadeVery Hard Palmer LakeSlightly Hard PaoniaSoft ParkerHard ParlinVery Hard ParshallSlightly Hard PeetzVery Hard PenroseVery Hard PeytonSlightly Hard PhippsburgSlightly Hard PierceSlightly Hard PineSlightly Hard PitkinVery Hard PlacervilleVery Hard PlattevilleSlightly Hard Pleasant ViewModerately Hard PowderhornSlightly Hard PuebloModerately Hard Pueblo WestModerately Hard RamahSlightly Hard RandSlightly Hard RangelyVery Hard Red CliffHard Red Feather LakeSlightly Hard RedvaleVery Hard RicoVery Hard RidgwayVery Hard RifleVery Hard RockvaleVery Hard Rocky FordVery Hard RoggenSlightly Hard RollinsvilleSoft RomeoSoft RushSlightly Hard RyeModerately Hard SaguacheModerately Hard SalidaSlightly Hard SanfordSoft SargentsVery Hard SedgwickVery Hard SeibertHard SiltVery Hard Silver PlumeSoft SilverthorneSlightly Hard SilvertonSoft SimlaVery Hard SlaterSlightly Hard SnowmassSoft Snowmass VillageSlightly Hard SnyderVery Hard SomersetSoft South ForkSlightly Hard SpringfieldVery Hard Steamboat SpringSlightly Hard SterlingVery Hard StonehamSlightly Hard StrasburgSlightly Hard StrattonModerately Hard Sugar CityVery Hard SwinkVery Hard TabernashSlightly Hard TellurideHard ThorntonSlightly Hard TimnathSlightly Hard TimpasVery Hard ToponasSlightly Hard TowaocModerately Hard TownerVery Hard TrincheraEstimatedVery Hard Twin LakesSlightly Hard Two United BankSlightly Hard United States AiSlightly Hard UtleyvilleVery Hard VailHard VernonVery Hard VictorSlightly Hard VilasVery Hard Villa GroveSlightly Hard VillegreenEstimatedVery Hard Virginia DaleSlightly Hard VonaVery Hard WaldenSlightly Hard WalshVery Hard WardSlightly Hard WatkinsSlightly Hard WattenburgSlightly Hard WeldonaVery Hard WellingtonSlightly Hard WestcliffeModerately Hard WestminsterSlightly Hard WestonEstimatedVery Hard WetmoreHard Wheat RidgeSlightly Hard WhitewaterVery Hard Wild HorseSlightly Hard WileyVery Hard WillardVery Hard WindsorSlightly Hard Winter ParkSoft WolcottHard Woodland ParkSlightly Hard Woody CreekSoft YampaSlightly Hard Yellow JacketModerately Hard YoderSlightly Hard YumaModerately Hard