Frederickson Water Hardness & Quality Report (2026)

Frederickson, Washington, in Pierce County — an unincorporated Pierce County community adjacent to Puyallup and Graham, in the southeast Pierce County suburban corridor — receives its municipal water from Tacoma Water or local Pierce County Water Districts, drawing from the Green River (Howard Hanson Dam, King County) or the Tacoma Water supply through the south Pierce County distribution network.

The extremely soft 20 mg/L hardness and very low TDS of 32.6 mg/L reflect the Green River or Tacoma Cascades source — among the softest water supplies in any US community. Tacoma Water's Green River supply is fed by the Howard Hanson Dam reservoir, draining the Cascade Range volcanic and insoluble Eocene sandstone watershed (entirely silicate, no carbonate). The result is near-distilled water quality, characteristic of the Pacific Northwest Cascade mountain supply.

At 20 mg/L, Frederickson's water is extremely soft — no scale ever forms, soap lathers maximally, and appliances achieve maximum lifespan. No descaling is needed. However, extremely soft water is slightly corrosive to plumbing — copper pipe leaching is a concern (particularly in older homes with copper plumbing). The PFAS level of 1.5 ppt is excellent — one of the lowest readings in the dataset, reflecting the protected Cascade watershed character and the limited PFAS industrial sources in the Frederickson area. A basic carbon filter is sufficient for any precautionary filtration.