Water Hardness in Washington

39 counties — Average 64.2 PPM (Moderately Hard)

22
13
3
1
Soft (56.4%) Moderate (33.3%) Hard (7.7%) Very Hard (2.6%)

Washington Water Hardness Map

Soft   Moderate   Hard   Very Hard

Hardest Water Counties

Island190 PPM
Washington

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All 39 Counties — By Water Hardness

CountyClassificationHardness
Adams Moderate 110 PPM
Asotin Soft 57.5 PPM
Benton Moderate 93.7 PPM
Chelan Soft 22 PPM
Clallam Soft 38 PPM
Clark Soft 56.7 PPM
Columbia Soft 44 PPM
Cowlitz Soft 17 PPM
Douglas Moderate 78.8 PPM
Ferry Moderate 93 PPM
Franklin Moderate 110 PPM
Garfield Moderate 79.5 PPM
Grant Hard 160 PPM
Grays Harbor Soft 24 PPM
Island Very Hard 190 PPM
Jefferson Soft 31 PPM
King Soft 40 PPM
Kitsap Moderate 65.5 PPM
Kittitas Soft 39.1 PPM
Klickitat Soft 34 PPM
Lewis Soft 21 PPM
Lincoln Hard 127 PPM
Mason Soft 35 PPM
Okanogan Moderate 88 PPM
Pacific Soft 21 PPM
Pend Oreille Moderate 79 PPM
Pierce Soft 41 PPM
San Juan Hard 166.5 PPM
Skagit Soft 24 PPM
Skamania Soft 23 PPM
Snohomish Soft 26.3 PPM
Spokane Moderate 88 PPM
Stevens Moderate 74 PPM
Thurston Soft 43.8 PPM
Wahkiakum Soft 18.5 PPM
Walla Walla Soft 54 PPM
Whatcom Soft 32 PPM
Whitman Moderate 81 PPM
Yakima Moderate 78 PPM

Source: USGS Water Quality Portal

Frequently Asked Questions

How hard is the water in Washington?

Washington has an average water hardness of 64.2 PPM, classified as moderately hard. Out of 39 counties, 22 have soft water, 13 moderately hard, 3 hard, and 1 very hard.

Which Washington counties have the hardest water?

Washington has 1 counties with very hard water (above 180 mg/L). See the county table above for a complete breakdown by hardness level.

How do I check water hardness for my Washington address?

Enter your ZIP code in the search box above to see your area's estimated water hardness, classification, and water utility information.