Building Safety in Lewis County, WA (2026)
2 rules for unincorporated Lewis County, Washington.
Verified from official government sources
Building Permits
Unincorporated Lewis County requires a permit from the Building Official before you construct, enlarge, alter, repair, move, demolish, or change the occupancy of a building, under the county's adopted IRC/IBC/IFC Section 105 and UPC Section 104. Small detached sheds under 200 square feet are exempt.
Building Permits Required, Lewis County
Some RestrictionsLewis County Code § 15.05.020(b)
IRC, IBC, IFC, Section 105, UPC Section 104 Permits Required Any owner or owner's authorized agent who intends to construct, enlarge, alter, repair, move, demolish or change the occupancy of a building or structure, or to erect, install, enlarge, remove, convert or replace any electrical, gas, mechanical or plumbing system, the installation of which is regulated by this code, or to cause any su...
Plumbing Permits
Unincorporated Lewis County plumbing work is governed by the 2021 Uniform Plumbing Code, adopted by reference along with Washington's WAC 51-56 and 51-57 plumbing appendices. Installing, replacing, or converting a plumbing system triggers the same Building Official permit requirement as other regulated systems.
Plumbing Permits, Lewis County
Some RestrictionsLewis County Code § 15.05.020(d)
The 2021 Uniform Plumbing Code (UPC), published by the International Association of Plumbing and Mechanical Officials (IAPMO) ... and adopting Chapter 51-56 WAC, and Plumbing Code Appendices, Chapter 51-57 WAC;
All Lewis County ordinances
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