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Water Hardness in Alaska

Across 2 measured cities — with 45 more covered by labeled county-level estimates — Alaska's median tap water hardness is 116.6 mg/L (6.8 gpg): moderately hard on the USGS scale. Below: every covered city, the state's hardest and softest water, and the geology that explains it.

Data updated July 6, 2026. Sources: utility-reported water quality data and USGS/EPA Water Quality Portal samples.

State Median
116.6
mg/L (6.8 gpg), measured cities
Measured Range
109.9-123.3
mg/L across measured cities
Measured Cities
2
utility-reported or computed values
County Estimates
45
96% of covered cities

Alaska Cities by Hardness Category

Measured cities only — labeled county estimates never enter the category counts or the median.

CategoryRangeMeasured citiesShare
Soft0-60 mg/L00.0%
Moderately hard60-120 mg/L150.0%
Hard120-180 mg/L150.0%
Very hard>180 mg/L00.0%

Hardest and Softest Water in Alaska

Measured values only; labeled county estimates and values under active dispute never rank.

Hardest water in Alaska

  1. Wasilla — 123.3 mg/L (7.2 gpg), hard
  2. Anchorage — 109.9 mg/L (6.4 gpg), moderately hard

Softest water in Alaska

  1. Anchorage — 109.9 mg/L (6.4 gpg), moderately hard
  2. Wasilla — 123.3 mg/L (7.2 gpg), hard

Every Covered City in Alaska

All 47 covered Alaska cities, sorted by population served. "County estimate" rows are labeled context values from USGS/EPA Water Quality Portal county sampling — they never enter the median above. City names link to each city's full water quality page.

CityHardness (mg/L)gpgCategoryData
Anchorage109.96.4Moderately hardComputed from Ca+Mg
Fairbanks110.06.4Moderately hardCounty estimate
Juneau120.07.0Moderately hardCounty estimate
Wasilla123.37.2HardComputed from Ca+Mg
Eielson AFB110.06.4Moderately hardCounty estimate
Kodiak15.90.9SoftCounty estimate
Sitka15.30.9SoftCounty estimate
Skagway57.03.3SoftCounty estimate
North Pole110.06.4Moderately hardCounty estimate
Seward27.41.6SoftCounty estimate
Kotzebue62.33.6Moderately hardCounty estimate
Petersburg5.10.3SoftCounty estimate
Dillingham34.02.0SoftCounty estimate
Wrangell59.03.5SoftCounty estimate
Bethel62.03.6Moderately hardCounty estimate
Haines120.07.0Moderately hardCounty estimate
Metlakatla37.12.2SoftCounty estimate
Craig37.12.2SoftCounty estimate
Hooper Bay114.36.7Moderately hardCounty estimate
Hoonah76.04.4Moderately hardCounty estimate
Klawock37.12.2SoftCounty estimate
Noorvik62.33.6Moderately hardCounty estimate
Buckland62.33.6Moderately hardCounty estimate
Salcha110.06.4Moderately hardCounty estimate
Noatak62.33.6Moderately hardCounty estimate
Thorne Bay37.12.2SoftCounty estimate
Big Lake55.63.3SoftCounty estimate
Kiana62.33.6Moderately hardCounty estimate
Kivalina62.33.6Moderately hardCounty estimate
Angoon76.04.4Moderately hardCounty estimate
Seldovia27.41.6SoftCounty estimate
Kake37.12.2SoftCounty estimate
Elim98.45.8Moderately hardCounty estimate
Koyuk98.45.8Moderately hardCounty estimate
Larsen Bay15.90.9SoftCounty estimate
Old Harbor15.90.9SoftCounty estimate
Pelican76.04.4Moderately hardCounty estimate
Coffman Cove37.12.2SoftCounty estimate
Mekoryuk62.03.6Moderately hardCounty estimate
Port Lions15.90.9SoftCounty estimate
Deering62.33.6Moderately hardCounty estimate
Ouzinkie15.90.9SoftCounty estimate
Palmer55.63.3SoftCounty estimate
Port Alexander37.12.2SoftCounty estimate
Karluk15.90.9SoftCounty estimate
Anchor Point27.41.6SoftCounty estimate
Jber70.64.1Moderately hardCounty estimate

Above 120 mg/L (7 gpg), scale is usually worth treating — see our water softener guide, or size a system with the hardness calculator & converter.

The Geology Behind Alaska's Water Hardness

Alaska sits in the Pacific maritime volcanic terrain region.

The Pacific Northwest, Alaska, and Hawaii share young volcanic bedrock - basalt and other igneous rock with little carbonate to dissolve - and most supplies come from heavy rainfall, snowmelt, or fast-recharging volcanic aquifers. Water simply does not stay in contact with soluble carbonate long enough to harden. That is why the USGS maps these states among the softest in the nation.

Source: USGS Water Science School - Hardness of Water

Alaska Water Hardness FAQ

Does Alaska have hard water?

On the whole, no — Alaska's statewide median sits below the hard threshold, though some cities run harder. The median is 116.6 mg/L (6.8 gpg) — moderately hard on the USGS scale, where anything above 120 mg/L (7 gpg) counts as hard. 1 of Alaska's 2 measured cities fall in the hard or very hard bands (50%), so check your own city rather than the state average.

How hard is tap water in Alaska?

Across the 2 Alaska cities with measured values in our index, the median hardness is 116.6 mg/L (6.8 gpg) — moderately hard on the USGS scale. Individual cities range from 109.9 to 123.3 mg/L, so check your own city rather than assuming the state number.

Which city in Alaska has the hardest water?

Wasilla has the hardest measured tap water in our Alaska index at 123.3 mg/L (7.2 gpg) — hard on the USGS scale. Rankings use measured utility values only; labeled county estimates and values under active dispute are excluded.

Do I need a water softener in Alaska?

1 of Alaska's 2 measured cities (50%) fall in the hard or very hard bands — above 120 mg/L (7 gpg), the level where most water treatment professionals suggest considering an ion-exchange softener. Hardness varies utility to utility, so look up your own city's value before sizing equipment.

How do I find my city's exact water hardness?

Enter your ZIP code in our free lookup at tapwaterdata.com/zip to see the value we hold for your Alaska city from utility-reported water quality data, check your water utility's annual Consumer Confidence Report (CCR), or use a home test-strip kit.

← Water hardness across the USInteractive hardness mapCalculator & converterFree ZIP-code hardness lookupData & methodology

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