Auburn Water Hardness & Quality Report (2026)
Water Hardness
3.2 grains per gallon
Source
reservoir
pH Level
7.5
neutral = 7.0
Lead
0.006 mg/L
✓ Below action level
TDS
120 mg/L
Est. Daily Cost
$0.14
energy & soap waste
Source: USGS Water Quality Portal · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In Auburn, your appliances are currently losing 7% efficiency due to mineral buildup.
| Appliance | In Auburn | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 7.8 yrs | 8.5 yrs | -8% |
| Washing Machine | 11.6 yrs | 12 yrs | -3% |
| Water Heater | 13.4 yrs | 15 yrs | -11% |
Regional Water Comparison
How Auburn compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Auburn, Washington | 54 mg/L | 2.6 ppt | 🟢 Soft | reservoir |
| Lea Hill, Washington | 25.5 mg/L | 1.7 ppt | 🟢 Soft | reservoir |
| Lakeland North, Washington | 46.5 mg/L | 2.3 ppt | 🟢 Soft | reservoir |
| Kent, Washington | 74.5 mg/L | 3.2 ppt | 🟡 Moderately Hard | reservoir |
| Federal Way, Washington | 68.5 mg/L | 3 ppt | 🟡 Moderately Hard | reservoir |
National Benchmark
How Auburn compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Auburn | 54 mg/L | 🟢 None |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Auburn's Water Unique?
Local geology and source profile
Auburn, Washington, in the Green River Valley of King County south of Seattle (home of Auburn Valley, the White River Amphitheatre, and a major BNSF rail junction), draws its municipal water supply from the Green River watershed via the City of Auburn Utilities Water Division and from wholesale Tacoma Water supply — the same Green River–based system that serves Tacoma (Howard Hanson Dam reservoir). The Green River originates in the Cascade Mountains of eastern King County. Water hardness in Auburn measures 54 mg/L — classified as moderately soft.
Auburn's soft supply reflects the Green River watershed's Pacific Northwest Cascade volcanic geology. The Green River drains the western Cascades of King County — underlain by: the Eocene Puget Group (sandstone and conglomerate — siliceous); Oligocene–Miocene Cascade andesite and basalt (volcanic formations — calcium-poor relative to carbonate geology); and the Snoqualmie Batholith (Cretaceous granodiorite — inherently low calcium). Howard Hanson Dam impounds the upper Green River in the Cascade Mountain foothills. The western Cascade volcanic and granodiorite terrain contributes minimal dissolved calcium, maintaining the moderately soft supply characteristic of King County's Cascade-fed municipal water systems.
With hardness at 54 mg/L, Auburn residents enjoy soft water with minimal scale challenges. Faucet aerators and showerheads develop deposits slowly — bi-monthly cleaning with citric acid solution is sufficient. City of Auburn Utilities and Tacoma Water consistently deliver water meeting all Washington DOH and EPA Safe Drinking Water Act requirements.
Geology & Source: Mixed supply from Green River Watershed (Howard Hanson Dam) via the City of Auburn Utilities Water Division and wholesale from Tacoma Water — the Green River Washington Cascades andesite and basalt watershed in King County; very soft supply at 54 mg/L — reflecting the Pacific Northwest Cascade volcanic terrain drainage.