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May 30, 2026
How to Choose a Lot for a Custom Home in Seattle: What Your Architect Wants You to Know
Choosing the right lot is the first and most consequential design decision you will make for your custom home. A great lot makes everything easier; a problematic lot adds cost and constraint to every phase of the project. Here is what your architect wants you to check before you make an offer.
Zoning and Buildable Area
Verify the lot’s zoning and calculate the buildable area after deducting setbacks, easements, critical area buffers, and any existing structures. A 10,000 sq ft lot might have only 3,500 sq ft of buildable area after constraints are applied.
Topography and Drainage
Sloped lots create opportunities for view homes and split-level designs — but also add cost for grading, retaining walls, and foundation work. Lots with existing drainage problems or steeply sloped areas adjacent to the building zone require careful evaluation.
Soil Conditions
Seattle has significant geological variability. Liquefaction-prone soils (fill areas near Elliott Bay, the Duwamish, Lake Union), expansive soils, and hillside slide risk all affect foundation costs. Get a geotechnical report before purchase on any lot with potential soil issues.
Sun and Views
Understand the lot’s solar orientation, shading from adjacent trees and buildings, and what views are available from buildable heights. Pacific Northwest homes benefit significantly from south-facing glass for passive solar gain.
Utilities
Verify that sewer, water, gas (if desired), and electrical service are available and at what cost to connect. Lots in rural or recently subdivided areas may require significant infrastructure investment.
Easements and CC&Rs
Review all recorded easements (utility, drainage, access) and CC&Rs that may restrict what can be built, materials that can be used, or require HOA design review approval.
Piper Cole Architects will review any lot you are considering and advise on what can be built, at what cost, and with what constraints — before you commit. Free consultation — call 425-753-6452.
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