Federal Way Water Hardness & Quality Report (2026)
Water Hardness
4 grains per gallon
Source
reservoir
pH Level
7.6
neutral = 7.0
Lead
0.007 mg/L
✓ Below action level
TDS
169.4 mg/L
Est. Daily Cost
$0.18
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 Federal Way, your appliances are currently losing 9% efficiency due to mineral buildup.
| Appliance | In Federal Way | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 7.3 yrs | 8.5 yrs | -14% |
| Washing Machine | 11.1 yrs | 12 yrs | -8% |
| Water Heater | 12.9 yrs | 15 yrs | -14% |
Regional Water Comparison
How Federal Way compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Federal Way, Washington | 68.5 mg/L | 3 ppt | 🟡 Moderately Hard | reservoir |
| Lakeland North, Washington | 46.5 mg/L | 2.3 ppt | 🟢 Soft | reservoir |
| Des Moines, Washington | 15 mg/L | 1.3 ppt | 🟢 Soft | reservoir |
| Auburn, Washington | 54 mg/L | 2.6 ppt | 🟢 Soft | reservoir |
| Kent, Washington | 74.5 mg/L | 3.2 ppt | 🟡 Moderately Hard | reservoir |
National Benchmark
How Federal Way compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Federal Way | 68.5 mg/L | 🟡 Low |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Federal Way's Water Unique?
Local geology and source profile
Federal Way, Washington, in south King County between Seattle and Tacoma, draws its municipal water supply through the Lakehaven Utility District, sourcing from Seattle Public Utilities (SPU) wholesale Cedar River water and local Green River Valley groundwater wells in the Green River Valley aquifer. The Lakehaven service area covers Federal Way and nearby Pierce and King County communities. SPU Cedar River water originates from Chester Morse Lake in the Cascade Range. Water hardness in Federal Way measures 68.5 mg/L — classified as moderately soft.
Federal Way's moderately soft supply reflects the blend of two soft Pacific Northwest sources. The SPU Cedar River component is very soft — originating in the Cascade Range with the Ohanapecosh Formation volcanic sequences and Quaternary glacial outwash. The Green River Valley groundwater in King County draws from the Quaternary glacial outwash aquifer of the Green River Valley — glaciofluvial sand and gravel deposited by Pleistocene glaciers. This glacial outwash is composed of crushed volcanic and metamorphic Cascade Range rock with minimal carbonate content, producing very soft alluvial aquifer water. The blend of Cedar River surface water and Green River Valley groundwater produces consistently moderately soft supply throughout Lakehaven's Federal Way service area.
With hardness at 68.5 mg/L, Federal Way residents experience minimal to moderate scale challenges. Faucet aerators and showerheads develop deposits slowly — bi-monthly cleaning with citric acid solution is sufficient. Dishwashers produce clean glassware. Lakehaven Utility District and Seattle Public Utilities consistently deliver water meeting all Washington DOH and EPA Safe Drinking Water Act requirements.
Geology & Source: Mixed supply from Cedar River Watershed (Seattle Public Utilities) and Green River Valley groundwater via the Lakehaven Utility District — the Cedar River drains the Cascade Range Ohanapecosh Formation volcanic terrain; the Green River Valley Quaternary glacial outwash aquifer in King County; combined moderately soft supply at 68.5 mg/L at the south King County Federal Way service area.