Phase 1 Environmental Site Assessment Cost in Washington
Typical Phase 1 ESA cost in Washington
$2,400–$5,400 per standard commercial parcel
Compiled from published 2026 industry cost guides (+20% vs. the $2,000-$4,500 national baseline). Full methodology on the cost data page.
Washington runs a meaningful premium above the national baseline in the published cost data, with Seattle driving most of the state's commercial due diligence volume. The Puget Sound region's aerospace manufacturing history and active port and shipping industry both add real historical-record complexity for consultants working in and around the city.
What tends to drive cost up in Washington
Seattle's aerospace manufacturing legacy (Boeing has operated in the region for decades) and its working waterfront and port facilities are recurring sources of recognized environmental conditions: solvent use, metal plating operations, and fuel storage tied to shipping are common findings in older industrial parcels.
Looking for a specific city? See Phase 1 ESA in Seattle, Washington, the largest commercial real estate market in the state.
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Frequently asked questions: Washington
Why is Washington above the national average?
Published cost guides put Washington about 20% above the national baseline, reflecting Seattle-area consultant rates and the record-review complexity of a region with a long aerospace and maritime industrial history.
Does Seattle's port history affect due diligence?
Yes. Working waterfront and port-adjacent parcels often carry a documented history of fuel storage, solvent use, or metal finishing that a Phase 1 ESA has to trace through historical sources under the ASTM E1527-21 standard.
Is Phase 1 ESA turnaround slower in Washington?
The standard national turnaround of 2 to 4 weeks generally applies; local records access speed, not the state itself, is usually the bigger factor in how long the records-review portion takes.