Is Washington tap water hard or soft?
Mostly not. 11 % of the 27 cities with published data in Washington have hard or very hard water (over 120 mg/L). The median is 2.8 gpg, from 0.7 gpg in Lynnwood to 9.3 gpg in Spokane.
We have published hardness data for 27 cities in Washington. The median is 2.8 gpg; the hardest water is in Spokane (9.3 gpg), the softest in Lynnwood (0.7 gpg).
11 % of these cities have hard or very hard water (over 120 mg/L).
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Cities in Washington, hardest first
| gpg | mg/L | ||
|---|---|---|---|
| Spokane | 9.3 | 159 | hard |
| Sunnyside | 7.8 | 133 | hard |
| Kennewick | 7.3 | 125 | hard |
| Vancouver | 6.4 | 110 | moderately hard |
| Moses Lake | 6.3 | 108 | moderately hard |
| Liberty Lake | 6.1 | 104 | moderately hard |
| Lake Forest Park | 5.9 | 101 | moderately hard |
| DuPont | 5 | 86 | moderately hard |
| Poulsbo | 4.7 | 80 | moderately hard |
| Lacey | 4.4 | 76 | moderately hard |
| Renton | 4 | 69 | moderately hard |
| Olympia | 3.4 | 58 | soft |
| Bremerton | 3.2 | 55 | soft |
| Bonney Lake | 2.8 | 48 | soft |
| Washougal | 2.1 | 36 | soft |
| Tacoma | 1.9 | 33 | soft |
| Anacortes | 1.8 | 30 | soft |
| Mercer Island | 1.6 | 28 | soft |
| Yakima | 1.6 | 27 | soft |
| Seattle | 1.5 | 26 | soft |
| Tukwila | 1.5 | 26 | soft |
| Shoreline | 1.4 | 25 | soft |
| Kirkland | 1.4 | 25 | soft |
| Bellevue, WA | 1.4 | 24 | soft |
| Bellingham | 1.3 | 22 | soft |
| Redmond | 1.2 | 21 | soft |
| Lynnwood | 0.7 | 13 | soft |
FAQ
Is Washington water hard or soft?
Mostly not. 11 % of the 27 cities we cover have hard or very hard water; the median is 2.8 gpg.
Which city in Washington has the hardest water?
Spokane, at 9.3 gpg, has the hardest water of the 27 cities with published data.
Which city in Washington has the softest water?
Lynnwood, at 0.7 gpg, has the softest water of the 27 cities with published data.
Do I need a water softener in Washington?
Above about 120 mg/L (7 gpg) scale builds up in water heaters, kettles and dishwashers, and a softener or at least regular descaling pays off. Look up your own city in the table: in Washington the values range from 0.7 gpg to 9.3 gpg.
On a private well? Well water hardness in Washington by county →