Hard Water Map

Michigan Water Hardness by County

Water in Michigan has a median hardness of 168 mg/L as CaCO₃ — "hard" on the USGS scale — based on 21,097 measurements at 4,874 monitoring stations. Huron County has the state's hardest measured water (350 mg/L); Gogebic County the softest (47.1). Rank: #17 of the 50 states and D.C.

Michigan water hardness map — what the numbers mean. Data verified 2026-07-22.

Of Michigan's 82 measured counties, 39 very hard, 27 hard, 12 moderately hard, and 4 soft. The hardest are Huron County (350 mg/L), Isabella County (344.5), and Sanilac County (340). Gogebic County is the softest at 47.1 mg/L (soft).

About 78% of Michigan's roughly 10 million residents in counties with gate-passing hardness data live where tap water is hard or worse.

Statewide, Michigan's median works out to 9.8 grains per gallon and ranks #17 of the 50 states and D.C. Across 21,097 measurements at 4,874 stations — 10,532 of them since 2000 — the middle 80% of readings fall between 45.5 and 320 mg/L. The public record runs from 1901 to 2026.

See where Michigan sits nationally on the national map, or what its number means on the hardness scale.

Download the Michigan water hardness map (PNG) — Water hardness by county in Michigan: 82 counties mapped from USGS/EPA data, statewide median 168 mg/L (hard); darker counties have harder water.

By county

Water hardness by county

The table lists all 82 measured Michigan counties, hardest first. Their medians span 350 mg/L in Huron County to 47.1 in Gogebic County — a 7.4× range. 1 more Michigan county lacks gate-passing data.

County water hardness, hardest first — median mg/L as CaCO₃.
CountyMedianBandResultsSitesNewest
Huron County350Very hard181741998
Isabella County344.5Very hard26242007
Sanilac County340Very hard79432016
Ingham County324Very hard2872182016
Eaton County322Very hard1141042013
Lenawee County320Very hard88522016
Monroe County318Very hard4161322014
Clinton County300Very hard2081732008
Shiawassee County295Very hard35281997
Ionia County290Very hard125392013
Lapeer County286Very hard86552016
Hillsdale County280Very hard110682016
Washtenaw County280Very hard6932712016
Livingston County277Very hard191862016
Branch County270Very hard175792022
Calhoun County270Very hard56372009
Oakland County270Very hard9414902023
Macomb County265Very hard814702023
Berrien County260Very hard259112022
Jackson County260Very hard105692022
Kalamazoo County260Very hard5281482013
Ottawa County260Very hard389272014
Saginaw County259.5Very hard612652015
Allegan County250Very hard436292014
St. Joseph County250Very hard98232013
Midland County248Very hard86312007
Bay County240Very hard200322013
Kent County230Very hard43412009
Tuscola County230Very hard33302008
Cass County220Very hard34262022
Genesee County220Very hard112672012
Menominee County220Very hard614472025
Arenac County210Very hard177162014
Barry County200Very hard47472009
Gladwin County200Very hard34242013
Montmorency County190Very hard30222010
Otsego County190Very hard49302010
Oscoda County186Very hard2192012
Alpena County180Very hard19582013
Antrim County170Hard22202023
Emmet County170Hard972010
Montcalm County170Hard37372008
Manistee County164Hard2,142612026
Cheboygan County160Hard238252013
Grand Traverse County160Hard193912013
Lake County160Hard37272010
Leelanau County160Hard68482013
Mason County160Hard162202013
Muskegon County160Hard97372011
Newaygo County160Hard355362013
Oceana County160Hard17152014
Ogemaw County160Hard42322009
Osceola County160Hard91152013
Benzie County150Hard46342013
Charlevoix County150Hard11112010
Crawford County150Hard53392007
Iosco County150Hard343302013
Van Buren County150Hard2171602009
Wexford County150Hard25172009
Presque Isle County145Hard16152010
Mecosta County140Hard27272008
Missaukee County132Hard11112006
Delta County130Hard7141662015
Alcona County120Hard10102007
Clare County120Hard23232013
Roscommon County120Hard12122007
Wayne County110Moderately hard645512021
Kalkaska County105Moderately hard16162009
Mackinac County100Moderately hard85142013
St. Clair County100Moderately hard529832016
Alger County93Moderately hard168862023
Schoolcraft County91Moderately hard322502014
Iron County72.5Moderately hard56432023
Luce County71.6Moderately hard154142010
Keweenaw County67Moderately hard227212023
Houghton County66Moderately hard122292024
Ontonagon County64.8Moderately hard323172024
Marquette County60.5Moderately hard1,2492472017
Dickinson County53Soft191472010
Baraga County50Soft1,7841102025
Chippewa County48Soft1,3541032016
Gogebic County47.1Soft103492014

ZIP codes

ZIP codes in Michigan

The ZIP codes below are grouped by the Michigan county they fall in. Each ZIP takes its county's measured median — shown in the group header — so this is a ZIP-to-county guide, not a separate reading for every ZIP. To check the water system serving a specific address, use the lookup.

Huron County · 350 mg/L · Very hard

4841348432†48441†48445†48467†48468†48470†48720†48725†48731†48754†48755†48759†

Isabella County · 344.5 mg/L · Very hard

48858†4885948878†48883†48893†48896†49310†

Sanilac County · 340 mg/L · Very hard

48401†48410†4841648419†48422†48426†48427†48434†48450†48453†48454†48456†48465†48466†484694847148472†48475†

Ingham County · 324 mg/L · Very hard

48819†48823488244882548840†48842488544886448892†48895489104891148912489154893349251†49264†49285†

Eaton County · 322 mg/L · Very hard

4881348821†4882748837†48861†48876†48890†4891749021†49076†49096†

Lenawee County · 320 mg/L · Very hard

49220†4922149228†4922949235†49236†49238†49247†49248†49253†49256†49265†49268†49276†49279†4928649287†49289†

Monroe County · 318 mg/L · Very hard

481174813148133†48140†4814448145†48157†48159†481604816148162†4816648177†48179†48182†49267†49270†

Clinton County · 300 mg/L · Very hard

48808†48820†48822†48831†48835†4885348866†48879†4889448906†

Shiawassee County · 295 mg/L · Very hard

48414†48418†4842948449†48460†48476†48817†48841†48848†48857†4886748872†

Ionia County · 290 mg/L · Very hard

48809†48815†48845†4884648849†48851†48860†48865†48870†48873†48875†48881

Lapeer County · 286 mg/L · Very hard

48003†48412†48421†48428†48440†48444†484464845548461†48464†4872748760†

Hillsdale County · 280 mg/L · Very hard

49227†49232†49242†49249†49250†4925249258†49262†49266†49271†49274†49282†49288†

Washtenaw County · 280 mg/L · Very hard

48103†4810448105†48108481094811848130†4815848176†48189†48190†48191†48197†48198†

Livingston County · 277 mg/L · Very hard

4811448116†48137†48139†48143†4816948353†48430†48816†4883648843†48855†

Branch County · 270 mg/L · Very hard

49028†49036†4908249089†49094†49255†

Calhoun County · 270 mg/L · Very hard

49011†49014†4901549017†49029†49033†49037†49051†49068†49092†49224†49245

Oakland County · 270 mg/L · Very hard

480094801748025480304803348034†4806748069480704807148072†480734807548076480834808448085480984816548167†48178482204823748301483024830448306†483074830948320483224832348324†48326483274832848329483314833448335483364834048341483424834648348†48350†48356†48357†48359†48360†4836248363†48367†48370†4837148374483754837748380†48381†4838248383†48386†48390483934844248462†

Macomb County · 265 mg/L · Very hard

48005†48015†4802148026480354803648038480424804348044480454804748048†48050†4805148062†48065†4806648080480814808248088480894809148092480934809448095†48096†48310483124831348314483154831648317†

Berrien County · 260 mg/L · Very hard

49022†49038†49084†4908549098†49101†49102†49103†49104†4910649107†49111†49113†4911549116†49117†49119†4912049125†49126†4912749128†49129†

Jackson County · 260 mg/L · Very hard

49201492024920349230†49233†49234†4923749240†49241†49246†4925449259†4926149263†49269†49272†49277†4928349284

Kalamazoo County · 260 mg/L · Very hard

4900149002†49004†49006†4900749008†49009†49012†4902449034†49048†49052†4905349074†49083†49087†49088†49097†

Ottawa County · 260 mg/L · Very hard

4940149403†494044940949417†4942449426†4942849430†49434†49435†49448†494564946049464†49534

Saginaw County · 259.5 mg/L · Very hard

48415†48417†48601486024860348604486074860948614†4861648623†4862648637†4863848649†4865548722†4872448734†

Allegan County · 250 mg/L · Very hard

4901049070†49078†49080†49323†49328†49335†49344†49348†4940649408†49419†49423†49450†49453

St. Joseph County · 250 mg/L · Very hard

49030†49032†4904049042†49066†4907249075†49091†49093†49099†

Midland County · 248 mg/L · Very hard

48618†48620†48628†486404864248657†

Bay County · 240 mg/L · Very hard

48611†48613†48631†48634†48650†4870648708†48710†4873248747†

Kent County · 230 mg/L · Very hard

49301†49302†4930649315†49316†49319†4932149326†49330†4933149341†49343†49345494184950349504495054950649507495084950949512495194952549544†4954649548

Tuscola County · 230 mg/L · Very hard

48435†48701†48723†4872648729†48733†48735†48741†48744†48746†48757†48767†48768

Cass County · 220 mg/L · Very hard

49031†49047†49061†49067†49095†49112†49130†

Genesee County · 220 mg/L · Very hard

48411†48420†484234843348436†4843748438†4843948451†48457†48458†48463†48473†485024850348504485054850648507†4850948519†4852948532†

Menominee County · 220 mg/L · Very hard

49812†49821†49847†49848†49858†49863†49873†49874†4988649887†49893†49896†

Arenac County · 210 mg/L · Very hard

48658†48659†48703†48749†48765†48766†

Barry County · 200 mg/L · Very hard

48897†49046†49050†4905849060†49073†49325†49333†

Gladwin County · 200 mg/L · Very hard

48610†48612†48624†48652†

Montmorency County · 190 mg/L · Very hard

49709†49746†

Otsego County · 190 mg/L · Very hard

49735†49751†49795†

Oscoda County · 186 mg/L · Very hard

48619†48621†48636†48647†49756†

Alpena County · 180 mg/L · Very hard

4970749744†49753†49766†

Antrim County · 170 mg/L · Hard

49611†49612†4961549622†49627†4962949648†49659†49727†49729†49730†

Emmet County · 170 mg/L · Hard

49701†49706†49716†49718†49722†49740†49755†4976449769†49770†

Montcalm County · 170 mg/L · Hard

48811†48818†48829†48834†4883848850†48852†48884†48885†48886†48888†48891†49322†49329†49339†49347†

Manistee County · 164 mg/L · Hard

49613†49614†49619†49625†49626†4963449645†49660†49675†49689†

Cheboygan County · 160 mg/L · Hard

49705†49717†49721†49749†49791†49799†

Grand Traverse County · 160 mg/L · Hard

49620†49637†49649†49685†49686†49690†49696†

Lake County · 160 mg/L · Hard

49304†49402†49623†49642†49644†49656†

Leelanau County · 160 mg/L · Hard

49621†49630†49636†49653†49654†49664†49670†49674†4968249684†

Mason County · 160 mg/L · Hard

49405†49410†49411†49431†49454†49458†

Muskegon County · 160 mg/L · Hard

49303†49318†49415†49425†49437†494404944149442†4944349444†49445†49451†49457†49461†

Newaygo County · 160 mg/L · Hard

49309†49312†49327†49337†49338†49349†49412

Oceana County · 160 mg/L · Hard

49420†49421†49436†49446†49449†49452†4945549459†

Ogemaw County · 160 mg/L · Hard

48635†48654†48661†48756†48761†

Osceola County · 160 mg/L · Hard

49631†49639†49655†49665†49677†49679†49688†

Benzie County · 150 mg/L · Hard

49616†49617†4962849635†49640†49643†49650†49683†

Charlevoix County · 150 mg/L · Hard

4971249713†49720†49782†49796†

Crawford County · 150 mg/L · Hard

49733†49738†

Iosco County · 150 mg/L · Hard

48730†48739†48743†48748†48750†48763†48770†

Van Buren County · 150 mg/L · Hard

4901349026†49027†49043†49045†49055†49056†49057†49063†4906449065†4907149079†49090†

Wexford County · 150 mg/L · Hard

49601†49618†49638†49663†49668

Presque Isle County · 145 mg/L · Hard

49743†49759†49765†49776†4977749779†

Mecosta County · 140 mg/L · Hard

49305†4930749320†49332†49336†49340†49342†49346†

Missaukee County · 132 mg/L · Hard

49632†49651†49657†49667†

Delta County · 130 mg/L · Hard

49807†49817†49829†49835†49837†49864†49872†49878†4989449895†

Alcona County · 120 mg/L · Hard

48705†48721†48728†48737†48738†48740†48742†48745†48762†49747†

Clare County · 120 mg/L · Hard

48617†48622†48625†48632†48633†

Roscommon County · 120 mg/L · Hard

48627†48629†4863048651†48653†48656†

Wayne County · 110 mg/L · Moderately hard

4810148111†48120481224812448125481264812748128481344813548138481414814648150481524815448164†48168481704817348174†4818048183481844818548186481874818848192481934819548201482024820348204482054820648207†482084820948210482114821248213482144821548216†4821748218†48219†4822148223482244822548226482274822848229†4823048233†48234482354823648238482394824048242†48243†

Kalkaska County · 105 mg/L · Moderately hard

49633†49646†49676†49680†

Mackinac County · 100 mg/L · Moderately hard

49719†49745†49757†49760†49762†49775†49781†49820†49827†49838†

St. Clair County · 100 mg/L · Moderately hard

48001†48002†48006†4801448022†48023†48027†48028†48032†48039†4804048041†48049†48054†48059†4806048063†48064†48074†48079†48097†

Alger County · 93 mg/L · Moderately hard

49806†49816†49822†49825†49826†49839†49862†49884†49891†

Schoolcraft County · 91 mg/L · Moderately hard

49836†49840†49854†49883†

Iron County · 72.5 mg/L · Moderately hard

49902†49903†4991549920†49927†49935†

Luce County · 71.6 mg/L · Moderately hard

49853†49868†

Keweenaw County · 67 mg/L · Moderately hard

49805†4990149918†49950†

Houghton County · 66 mg/L · Moderately hard

49905†4991349916†49917†4992149922†49930†4993149934†49942†49945†49952†49955†49958†49961†49963†49965†49967†

Ontonagon County · 64.8 mg/L · Moderately hard

49910†49912†49925†49929†49948†49953†49960†49971†

Marquette County · 60.5 mg/L · Moderately hard

49808†49814†49818†49833†49841†49849†49855†49866†49871†49879†49880†49885†

Dickinson County · 53 mg/L · Soft

49801†4980249815†49831†49834†49852†49870†49876†49877†49881†49892†

Baraga County · 50 mg/L · Soft

49861†49908†49919†49946†49962†49970†

Chippewa County · 48 mg/L · Soft

49710†49715†49724†49725†49726†49728†49736†49748†4975249768†49774†49780†49783†4978449788†49793†

Gogebic County · 47.1 mg/L · Soft

49911†49938†49947†49959†49968†49969†

† 684 ZIP codes are not served by a mapped community water system — most are private-well areas. See well water hardness.

Check any ZIP's utility and hardness →

Source

Groundwater vs surface water

Michigan's groundwater measures harder than its surface water — 284 mg/L across 3,108 samples versus 160 across 17,956, about 1.8× harder. Wells draw from groundwater, so well owners in Michigan tend to see the harder number — 284 mg/L, very hard. Groundwater readings there run 120 to 514 mg/L across the middle 80% of samples. The comparison draws on 2,526 groundwater and 2,339 surface-water monitoring sites; 40 readings above 2,000 mg/L were logged but held out of the medians as outliers.

Groundwater (wells)

284 mg/L as CaCO₃ · 3,108 results at 2,526 stations.

Surface water (rivers, lakes)

160 mg/L as CaCO₃ · 17,956 results at 2,339 stations.

Groundwater measures about 1.8× harder than surface water here.

Chemistry

Water chemistry in Michigan

Beyond the hardness number, Michigan's water carries a fuller chemical signature — here is how its measured parameters compare to national benchmarks.

TDS

250 mg/L · n=3,724

250 mg/L — about 1.1× the national county median of 226, consistent with hard, mineral-rich water.

pH

8 pH · n=12,698

pH 8 — within the EPA secondary range of 6.5–8.5, on the alkaline side.

Alkalinity

124 mg/L as CaCO3 · n=11,396

124 mg/L — substantial buffering capacity, which resists pH swings.

Calcium : Magnesium

41.4 : 11.8 mg/L ≈ 3.51 : 1 · n=7,385

Calcium is about 68% of Michigan's hardness (41.4 mg/L Ca to 11.8 mg/L Mg), a little in line with than the national ~68% calcium share.

Parameter medians may include a small share of quality-control samples; the hardness lane is fully QC-filtered.

Aquifers

Major aquifers under Michigan

3 aquifer systems supply much of Michigan's measured groundwater.

  • Silurian-Devonian aquifers — median 326 mg/L across 98 samples at 88 sites: very hard.
  • Pennsylvanian aquifers — median 310 mg/L across 432 samples at 357 sites: very hard.
  • Sand and gravel aquifers (glaciated regions) — median 292 mg/L across 1,265 samples at 880 sites: very hard.

Together these systems account for 1,795 measured samples at 1,325 sites. Aquifer medians pool samples across a whole system and can mask local variation — see the national aquifer map for how these compare across states.

Trend

Hardness over time

1940s2020s280

Michigan's decade median moved from 280 mg/L in the 1940s to 170 in the 2020s. Over the series, the decade median peaked at 280 mg/L in the 1940s and bottomed at 130 in the 1970s. Decade medians reflect where and what agencies sampled in each era, not just changes in the water itself.

Scale

Where Michigan sits on the scale

On the USGS scale, Michigan's 168 mg/L is hard — 9.8 grains per gallon, above the 120 mg/L hard cutoff, below very hard.

SoftModerately hardHardVery hard60 · 3.5 gpg120 · 7.0 gpg180 · 10.5 gpg168 mg/L — Hard
Harder than 56% of the 2,977 measured county medians.

At 168 mg/L (9.8 gpg), water-softener owners in Michigan typically set their unit to this hardness — settings calculator.

Questions

Frequently asked questions

Is Michigan's water hard?
Michigan's median hardness is 168 mg/L as CaCO₃, "hard" on the USGS scale and 1.2× the national county median of 140 mg/L. About 78% of residents in measured counties have hard-or-worse water.
Which county in Michigan has the hardest water?
Huron County, with a median of 350 mg/L as CaCO₃ across 181 measurements.
Is well water harder than city water in Michigan?
Groundwater measures harder here — about 1.8× the surface water — so wells tend to run harder (groundwater 284 vs surface water 160 mg/L).
How do I find my exact hardness in Michigan?
Search your ZIP on the lookup tool, read your utility's Consumer Confidence Report, or test at home with a kit.
Is Michigan's water harder than the national average?
Yes. Michigan's median of 168 mg/L is 1.2× the national county median of 140 mg/L, and Michigan ranks #17 of the 50 states and D.C.

Compare

States with similar hardness

Two states measure closest to Michigan's 168 mg/L: Colorado at 157 mg/L and Montana at 183 mg/L. Michigan measures harder than 68% of states. Browse the full ranking on the statistics page.

More: hardness scale · check your address · national statistics · the national map.

By . Source: USGS/EPA Water Quality Portal — 21,097 Michigan measurements. Data last verified . Methodology.

Cite this page: “Michigan Water Hardness by County.” Hard Water Map. Retrieved 2026-07-22, https://hardwatermap.com/water-hardness/michigan/