Hardest Water in Washington
26 cities ranked by water hardness. Spokane tops the list at 104 PPM.
Washington's water hardness varies significantly by city and water source. The state average across our database is 33 PPM, which is relatively soft. Most homes do not need a water softener. 0% of cities we track in Washington have hardness above 120 PPM.
Kirkland has the softest water at just 12 PPM. No softener is needed.
| # | City | PPM | GPG | Level | Softener? |
|---|---|---|---|---|---|
| 1 | Spokane | 104 | 6.1 | Moderately Hard | Optional |
| 2 | Pasco | 100 | 5.8 | Moderately Hard | Optional |
| 3 | Kennewick | 95 | 5.6 | Moderately Hard | Optional |
| 4 | Richland | 92 | 5.4 | Moderately Hard | Optional |
| 5 | Wenatchee | 70 | 4.1 | Moderately Hard | Optional |
| 6 | Bellevue | 26 | 1.5 | Slightly Hard | No |
| 7 | Everett | 26 | 1.5 | Slightly Hard | No |
| 8 | Yakima | 25 | 1.5 | Slightly Hard | No |
| 9 | Redmond | 25 | 1.5 | Slightly Hard | No |
| 10 | Renton | 22 | 1.3 | Slightly Hard | No |
| 11 | Seattle Downtown | 22 | 1.3 | Slightly Hard | No |
| 12 | Tacoma | 21 | 1.2 | Slightly Hard | No |
| 13 | Seattle | 20 | 1.2 | Slightly Hard | No |
| 14 | Auburn | 20 | 1.2 | Slightly Hard | No |
| 15 | Lacey | 20 | 1.2 | Slightly Hard | No |
| 16 | Tacoma South | 20 | 1.2 | Slightly Hard | No |
| 17 | Federal Way | 18 | 1.1 | Slightly Hard | No |
| 18 | Marysville | 18 | 1.1 | Slightly Hard | No |
| 19 | Burien | 18 | 1.1 | Slightly Hard | No |
| 20 | Olympia | 17 | 1 | Slightly Hard | No |
| 21 | Kent | 16 | 0.9 | Soft | No |
| 22 | Lake Stevens | 16 | 0.9 | Soft | No |
| 23 | Sammamish | 15 | 0.9 | Soft | No |
| 24 | Bellingham | 15 | 0.9 | Soft | No |
| 25 | Vancouver | 13 | 0.8 | Soft | No |
| 26 | Kirkland | 12 | 0.7 | Soft | No |
Frequently Asked Questions
What is the average water hardness in Washington?
Across 26 cities in our database, the average water hardness in Washington is 33 PPM (1.9 GPG). This ranges from 12 PPM in Kirkland to 104 PPM in Spokane.
Do I need a water softener in Washington?
It depends on your city. 0% of Washington cities in our database (0 of 26) have hardness above 120 PPM where a softener provides measurable benefit. Check your specific city above.
Which Washington city has the softest water?
Kirkland has the softest water in Washington at 12 PPM (0.7 GPG). No water softener is needed at this level.
What causes hard water in Washington?
Hard water in Washington is caused by dissolved calcium and magnesium from the local geology. Most of the state has favorable geology with granite, metamorphic, or volcanic rock that contributes minimal dissolved minerals.