Water Hardness in Maryland
Average: 95 PPMSlightly Hard399 cities461 water systems
State report
Is Maryland Water Hard or Soft?
Maryland water is slightly hard on average at 95 PPM (5.6 GPG). Local readings can vary by utility, aquifer, treatment plant, and private well use.
State average
95 PPM
Slightly Hard
Local coverage
399 cities
461 water systems
Source profile
415 ZIPs
direct or USGS-backed
92% of covered ZIPs use treated-water records or USGS monitoring, so the state report has relatively strong source support.
State data profile
How to read the Maryland 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
415 of 450
92% use treated-water records or USGS monitoring.
Estimated ZIP values
35 ZIPs
8% 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
95 PPM
Slightly Hard
Coverage
399 cities
461 water systems in the state rollup.
Data Source Coverage
ZIP-level source mix for Maryland; higher direct and USGS coverage means less reliance on regional estimates.
450 ZIPs covered
Verified treated water
Utility, CCR, or state treated-water records
50%
225 ZIPs
High-confidence USGS
Environmental monitoring matched to local systems
42%
190 ZIPs
Estimated
Nearby, county, or state-level fallback values
8%
35 ZIPs
In Maryland, 50% of ZIPs use verified treated-water records, 42% use high-confidence USGS monitoring, and 8% use estimates that should be confirmed locally for treatment decisions.
What the Data Shows in Maryland
Most classified ZIPs in Maryland are below the hard-water threshold, though local systems can still vary.
Maryland has unusually strong treated-water coverage: 50% of ZIPs use utility, CCR, or state treated-water records.
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
Soft25% (111)
Slightly Hard26% (115)
Moderately Hard47% (212)
Hard2% (11)
Very Hard0% (1)
Treatment Takeaway
Maryland 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 Maryland, so these pages are useful for comparing local patterns before confirming your home's exact hardness.
Source-Backed Water Systems in Maryland
Large systems with treated-water reports or USGS monitoring behind the state rollup.
| Water system | Hardness | Source label | Population |
|---|---|---|---|
| Washington Suburban Sanitary Commission MD0150005 - Montgomery County | 120 PPM Moderately Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 1,900,000 |
| City Of Baltimore MD0300002 - Baltimore City County | 120 PPM Moderately Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 1,600,000 |
| Glen Burnie-Broadneck MD0020017 - Anne Arundel County | 85 PPM Slightly Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 290,606 |
| New Design - Frederick County MD0100030 - Frederick County | 120 PPM Moderately Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 74,911 |
| Crofton-Odenton MD0020008 - Anne Arundel County | 85 PPM Slightly Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 62,986 |
| Fort George G. Meade MD0020012 - Anne Arundel County | 85 PPM Slightly Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 62,234 |
| City Of Frederick MD0100015 - Frederick County | 120 PPM Moderately Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 54,000 |
| City Of Rockville MD0150003 - Montgomery County | 120 PPM Moderately Hard | Annual Water Quality Report Verified - Annual Water Quality Report | 52,000 |
Useful Maryland City Pages
Shortcuts to city pages backed by more ZIP-code or water-system data.
Cities With More Local Data
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 | Carrollton | Hard (209 PPM) |
| 2 | North East | Moderately Hard (160 PPM) |
| 3 | Perryville | Moderately Hard (134 PPM) |
| 4 | Dunkirk | Moderately Hard (127 PPM) |
| 5 | Baltimore | Moderately Hard (120 PPM) |
| 6 | Bethesda | Moderately Hard (120 PPM) |
| 7 | Colesville | Moderately Hard (120 PPM) |
| 8 | Frederick | Moderately Hard (120 PPM) |
| 9 | Gaithersburg | Moderately Hard (120 PPM) |
| 10 | Germantown | Moderately Hard (120 PPM) |
Top 10 Softest Water Cities
| # | City | Hardness |
|---|---|---|
| 1 | Williamsport | Soft (11 PPM) |
| 2 | California | Soft (12 PPM) |
| 3 | Parsonsburg | Soft (23 PPM) |
| 4 | Fruitland | Soft (23 PPM) |
| 5 | Salisbury | Soft (23 PPM) |
| 6 | Delmar | Soft (25 PPM) |
| 7 | Pisgah | Soft (39 PPM) |
| 8 | Newburg | Soft (40 PPM) |
| 9 | La Plata | Soft (41 PPM) |
| 10 | Saint Charles | Soft (41 PPM) |
All Cities in Maryland
City pages marked Estimated use fallback values and should be confirmed with local testing or utility data.
AbellModerately HardAberdeenSlightly HardAberdeen ProvingSlightly HardAbingdonSlightly HardAccidentSlightly HardAccokeekSoftAdelphiModerately HardAllenSoftAnnapolisSlightly HardAnnapolis JunctiSoftAquascoModerately HardArnoldSlightly HardAshtonModerately HardAspen HillModerately HardAvenueModerately HardBainbridgeSlightly HardBaldwinModerately HardBaltimoreModerately HardBarclayModerately HardBarnesvilleModerately HardBartonModerately HardBeallsvilleModerately HardBel AirSlightly HardBel AltonSoftBelcampSlightly HardBeltsvilleModerately HardBenedictSoftBentley SpringsModerately HardBerlinSlightly HardBethesdaModerately HardBettertonSlightly HardBig PoolSoftBig SpringSoftBishopvilleSlightly HardBivalveSoftBladensburgModerately HardBloomingtonSoftBowieModerately HardBoydsModerately HardBozmanSoftBrandywineModerately HardBrentwoodModerately HardBrinklowModerately HardBrookevilleModerately HardBrooklyn CurtisSlightly HardBroomes IslandModerately HardBrunswickSlightly HardBryans RoadSoftBryantownSoftBuckeystownModerately HardBurkittsvilleModerately HardBurtonsvilleModerately HardBushwoodModerately HardCabin JohnModerately HardCaliforniaSoftCallawayModerately HardCambridgeSlightly HardCape Saint ClairSlightly HardCapital HeightsModerately HardCarrolltonHardCarrolltowneHardCatonsvilleModerately HardCeciltonSlightly HardCentrevilleSoftCharlestownSlightly HardCharlotte HallSoftCheltenhamModerately HardChesapeake BeachSlightly HardChesapeake CitySlightly HardChesterSoftChestertownSlightly HardChevy ChaseModerately HardChurch CreekSlightly HardChurch HillSoftChurchtonSlightly HardChurchvilleSlightly HardClaiborneSoftClarksburgModerately HardClarksvilleSoftClementsModerately HardClintonModerately HardCobb IslandSoftCockeysville HunModerately HardColesvilleModerately HardCollege ParkModerately HardColoraSlightly HardColtons PointModerately HardColumbiaSoftConowingoSlightly HardCooksvilleSoftCordovaSoftCorriganvilleModerately HardCrapoSlightly HardCresaptownModerately HardCrisfieldSoftCrocheronSlightly HardCroftonSlightly HardCrownsvilleSlightly HardCrumptonModerately HardDamascusModerately HardDameronModerately HardDanielsSoftDarlingtonSlightly HardDarnestownModerately HardDavidsonvilleSlightly HardDaytonSoftDeal IslandModerately HardDealeSlightly HardDeer ParkSlightly HardDelmarSoftDentonSoftDerwoodModerately HardDickersonModerately HardDistrict HeightsModerately HardDoubsModerately HardDowellModerately HardDraydenModerately HardDundalk SparrowsModerately HardDunkirkModerately HardEarlevilleSlightly HardEast New MarketSlightly HardEastonSoftEdenSoftEdgewater BeachSlightly HardEdgewoodSlightly HardElk MillsSlightly HardElktonSlightly HardEllerslieModerately HardEllicott CitySoftEmmitsburgModerately HardEssexModerately HardEudowoodModerately HardEwellModerately HardFahrney Keedy MeSoftFair PlaySoftFallstonSlightly HardFaulknerSoftFederalsburgSoftFishing CreekSlightly HardFlintstoneModerately HardForest HillSlightly HardForkModerately HardFort George G MeSlightly HardFort HowardModerately HardFort RitchieSoftFort WashingtonModerately HardFowbelsburgModerately HardFrederickModerately HardFreelandModerately HardFriendshipSlightly HardFriendsvilleModerately HardFrostburgModerately HardFruitlandSoftFultonSoftFunkstownSoftGaithersburgModerately HardGalenaModerately HardGalesvilleSlightly HardGambrillsSlightly HardGarrett ParkModerately HardGeorgetownSlightly HardGermantownModerately HardGibson IslandSlightly HardGirdletreeSlightly HardGlen ArmVery HardGlen BurnieSlightly HardGlen EchoModerately HardGlencoeModerately HardGlenelgSoftGlenn DaleModerately HardGlenwoodSoftGlyndonModerately HardGoldsboroModerately HardGracehamSlightly HardGraniteModerately HardGrasonvilleSoftGreat MillsModerately HardGreenbeltModerately HardGreenmountHardGreensboroSoftGunpowderSlightly HardGwynn OakModerately HardHagerstownSoftHalethorpeSoftHancockSoftHanoverSoftHarmansSlightly HardHarwoodSlightly HardHavre De GraceSlightly HardHebronSoftHendersonModerately HardHerefordModerately HardHighlandSoftHillsboroModerately HardHollywoodSoftHughesvilleSoftHuntingtownSlightly HardHyattsvilleModerately HardHydesModerately HardIjamsvilleModerately HardInglesideModerately HardIssueSoftJacksonvilleModerately HardJarrettsvilleSlightly HardJeffersonModerately HardJenningsSlightly HardJessupSlightly HardJoppaSlightly HardKeedysvilleSoftKennedyvilleSlightly HardKensingtonModerately HardKeymarModerately HardKingsvilleModerately HardKnoxvilleModerately HardLa PlataSoftLandoverModerately HardLandover HillsModerately HardLanhamModerately HardLaurelSlightly HardLaytonsvilleModerately HardLeonardtownSoftLexington ParkSoftLibertytownModerately HardLinkwoodSlightly HardLinthicum HeightSlightly HardLittle OrleansModerately HardLonaconingModerately HardLothianSlightly HardLukeModerately HardLusbySlightly HardLuthervilleModerately HardMaddoxModerately HardMadisonSlightly HardManchesterHardMardela SpringsSoftMarion StationSlightly HardMarriottsvilleHardMarydelModerately HardMaryland LineModerately HardMasseyModerately HardMaugansvilleSoftMccooleModerately HardMcdanielSoftMechanicsvilleModerately HardMiddle RiverModerately HardMiddletownModerately HardMidlandModerately HardMidlothianModerately HardMillersvilleSlightly HardMillingtonSlightly HardMitchellvilleSlightly HardMonroviaModerately HardMontpelierModerately HardMount AirySlightly HardMount RainierModerately HardMount SavageModerately HardMyersvilleSlightly HardNanjemoySoftNanticokeSoftNaval AcademySlightly HardNew MarketModerately HardNew WindsorHardNewarkSlightly HardNewburgSoftNewcombSoftNorth BeachSlightly HardNorth EastModerately HardNottinghamModerately HardOcean CitySlightly HardOdentonSlightly HardOldtownModerately HardOlneyModerately HardOwingsModerately HardOwings MillsModerately HardOxfordSoftOxon HillModerately HardPark HallModerately HardParkvilleModerately HardParsonsburgSoftPatapscoHardPatuxent RiverSoftPerry HallModerately HardPerry PointSlightly HardPerrymanSlightly HardPerryvilleModerately HardPikesvilleModerately HardPiney PointModerately HardPisgahSoftPittsvilleSoftPocomoke CitySlightly HardPoint Of RocksModerately HardPomfretSoftPoolesvilleModerately HardPort RepublicSlightly HardPort TobaccoSoftPotomacModerately HardPrestonSoftPrince FrederickSlightly HardPrincess AnneSoftPylesvilleSlightly HardQuanticoSoftQueen AnneSoftQueenstownSoftRandallstownModerately HardRawlingsModerately HardReisterstownModerately HardRhodesdaleSlightly HardRidgeModerately HardRidgelySoftRising SunSlightly HardRisonSoftRivaSlightly HardRiverdaleModerately HardRiviera BeachSlightly HardRock HallSoftRocksSlightly HardRockvilleModerately HardRocky RidgeModerately HardRohrersvilleSoftRosedaleHardRoyal OakSoftSabillasvilleModerately HardSaint CharlesSoftSaint InigoesModerately HardSaint LeonardSlightly HardSaint MichaelsSoftSalisburySoftSandy SpringModerately HardSang RunModerately HardSavageSoftScotlandModerately HardSecretarySlightly HardSevernSlightly HardSeverna ParkSlightly HardShady SideSlightly HardShallmarSoftSharpsburgSoftSharptownSoftSherwoodSoftSherwood ForestSlightly HardShowellSlightly HardSilver SpringModerately HardSmithsburgSoftSnow HillSlightly HardSolomonsModerately HardSpencervilleModerately HardSpring GapModerately HardStevensvilleSoftStill PondModerately HardStocktonSlightly HardSudlersvilleSlightly HardSuitlandModerately HardSunderlandModerately HardSwantonSoftTakoma ParkModerately HardTall TimbersModerately HardTaneytownHardTaylors IslandSlightly HardTemple HillsModerately HardTilghmanSoftToddvilleSlightly HardTracys LandingSlightly HardTrappeSoftTuscaroraModerately HardTyaskinSoftTylertonSoftUniontownHardUnionvilleHardUpper FairmountModerately HardUpper FallsModerately HardUpper MarlboroModerately HardValley LeeModerately HardViennaSlightly HardWaldorfSoftWalkersvilleModerately HardWarwickSlightly HardWashington GroveModerately HardWelcomeSoftWest BethesdaModerately HardWest FriendshipSoftWest HyattsvilleModerately HardWest RiverSlightly HardWestoverModerately HardWhaleysvilleSlightly HardWheatonModerately HardWhite HallSlightly HardWhite MarshModerately HardWhite PlainsSoftWhitefordSlightly HardWillardsSoftWilliamsburgSlightly HardWilliamsportSoftWingateSlightly HardWittmanSoftWoodbineSoftWoodsboroSlightly HardWoolfordSlightly HardWortonModerately HardWye MillsSoft