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Septic companies in Seattle, WA

8 septic companies on record in Seattle, King County.

Companies
8
County
King

What the ground in Seattle is like

The USDA soil survey rates every mapped parcel for its suitability as a septic drain field. Across Seattle's 84.0 square miles, 100.0% of the rated ground is classed "Very limited", meaning restrictions severe enough that a conventional field is often unsuitable and an engineered system may be required.

The limiting features the survey records most often here:

  • Depth to saturated zone100.0%
  • Slope53.8%
  • Filtering capacity23.3%

The most common soil series underfoot: Alderwood, Anthraltic Xerorthents.

This is survey data for the area, not a substitute for a site evaluation on your own lot. A soil scientist or your county health department tests the actual parcel, and the result can differ from the map.

USDA NRCS SSURGO, ENG Septic Tank Absorption Fields · 17 map units · read 2026-08-30

Septic companies in Seattle

Ordered by verification score. The score counts records we could check and is not a judgment about workmanship. None of these has been checked against a state roster yet, so every licence here reads as unverified.

Nearby

All septic companies in Washington · King County

How these are ranked

By verification score, out of 100, across six checks published in full on how we rank. No company paid to appear here and none can pay to rank higher.