Mill Creek Building Department

WSEC-R 2021 energy code compliance resources for builders and contractors in Mill Creek, Snohomish County.

Building Department

Mill Creek Community Development

Address
15720 Main St, Mill Creek, WA 98012
Hours
M-F 8am-5pm
Notes
uses MyBuildingPermit.com

Last verified: 2026-04-19

Submittal notes

These apply at Snohomish County County level — verify city-specific items directly with Mill Creek Community Development.

  • Everett: Everett requires cross-sections and framing plans to explicitly show whole-house ventilation duct routing, exhaust outlet locations, and crawl space ventilation calculations — R406 energy credit text must also appear on the architectural drawings, not only on the prescriptive worksheet.
  • Snohomish County: Snohomish County: Native Growth Protection Area (NGPA) boundaries must be marked on site plans alongside WSEC-R calculations.

Code environment

Climate Zone

CZ4

Western WA — moderate climate requirements.

Radon Zone

Zone 2

Moderate potential — mitigation recommended.

Learn more →

Ready to check your compliance?

wsec.ai generates a complete R406 credit summary you can submit with your permit application to Mill Creek Community Development.

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