Lewis County, WA Accessory Structures: Garage Conversions (2026)
Garage conversion rules in Lewis County, WA, sometimes called garage-to-ADU or accessory living unit conversions, govern permits, ceiling height, egress, and parking replacement.
Key Facts
- Max ADUs per lot
- Two, with a single-family structure
- Garage conversion
- Exempt from setback and lot coverage
- Still required
- All other applicable building laws
- Detached ADU on alley
- May sit directly on lot line
- Applies to
- Packwood and Onalaska Small Town UGAs
Summary
Lewis County's Small Town UGA code lets a homeowner convert an existing garage into an accessory dwelling unit even if the conversion violates the property's setback or lot coverage standards, as long as the finished ADU meets every other applicable building and land use requirement.
(1) There shall be no more than two accessory dwelling units per lot in conjunction with a single-family structure. (2) A garage may be converted to an ADU, even if it violates existing requirements for setbacks or lot coverage. The converted ADU shall meet all other applicable laws and requirements.
Full Breakdown
130 governs accessory dwelling units within the Packwood and Onalaska Small Town Urban Growth Areas of unincorporated Lewis County. Subsection (1) caps the total at no more than two ADUs per lot in conjunction with a single-family structure. Subsection (2) is the garage conversion rule: a garage may be converted to an ADU even if the conversion violates existing setback or lot coverage requirements, provided the converted unit meets all other applicable laws, including building code, sewage and water requirements. 17. Subsection (3) separately allows a detached ADU to be sited directly on a lot line where that line abuts a public alley, unless the county routinely plows snow on the alley, in which case the ADU must be set back enough to keep the alley clear.
40 LCC) where applicable, a conversion cannot skip septic capacity or structural review even though it is exempt from the zone's setback and coverage math. The section was adopted by Ord. 1367 (Exh. C) in 2025.
Violations & Fines
Occupying or building a garage-conversion ADU that does not meet the applicable building, sewage or fire-access standards is a civil infraction under LCC § 17.07.010, processed through Chapter 1.20 LCC's code enforcement program, with each day of continued noncompliance a separate offense; the same conduct can also be prosecuted as a misdemeanor, and the county may withhold further permits until the ADU is brought into compliance.
Frequently Asked Questions
Can I convert my garage into an ADU if it's too close to the property line?
How many ADUs can I have on one lot in unincorporated Lewis County?
Can a detached ADU sit right on my property line?
Sources & Official References
Other rules in Lewis County
Compare Lewis County to another location·View the Washington accessory structures overview
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