Franklin County, WA Accessory Structures: Tiny Homes (2026)
Tiny home rules in Franklin County, WA, covering tiny houses on wheels (THOWs), park model RVs, and tiny home on foundation builds, determine where they are legal and how they get permitted.
Key Facts
- Governing tool
- Binding site plan (Chapter 16.36)
- Definition used
- Tiny homes with wheels per RCW 35.21.686
- Health review required
- Benton-Franklin Health District written approval
- Planning director decision window
- 30 days of complete application
- Survey required
- By a WA-licensed land surveyor
- Applies
- Countywide, unincorporated Franklin County
Summary
In unincorporated Franklin County, leasing an individual parcel for a tiny house or tiny home with wheels (as defined in RCW 35.21.686) is only allowed through the binding site plan process under Franklin County Code § 16.36.020(B), the same land-division tool used for mobile home parks, and the site plan must comply with every applicable mobile home park and zoning regulation.
The division of property by the binding site plan process may only be used for the following:A.Division of land for the sale or lease of commercial or industrially zoned property as provided in the Franklin County zoning regulations;B.The division of land for the purposes of leasing space for mobile homes, tiny houses or tiny homes with wheels as defined in RCW 35.21.686, or travel trailers so long as the site plan complies with all applicable mobile home park and zoning regulations;C.The division of land involving improvements constructed or to be constructed thereon that will be one or more condominiums or owned by an association or other legal entity. ... F.Written approval from the Benton-Franklin Health District. ... An application for binding site plan approval shall be approved with conditions, returned to the applicant for modifications or denied within thirty (30) days of its receipt by the planning director unless the applicant agrees, in writing, to an extension of this period.
Full Breakdown
Franklin County doesn't have a stand-alone tiny-home ordinance; instead it folds tiny homes with wheels into its binding site plan chapter, the alternative subdivision method it also uses for mobile home parks, travel trailers, and commercial condominiums. 020(B) authorizes dividing land specifically for leasing space to mobile homes, tiny houses or tiny homes with wheels, but only if the site plan complies with all applicable mobile home park and zoning regulations, meaning a tiny-home lease lot is held to the same development standards as a mobile home park space, not a lighter standard.
60. 080(A), unless the applicant agrees in writing to extend that window. The binding site plan, once recorded with the Franklin County Auditor, binds every lot created under it; it can only be altered through the same review process and can only be vacated by the planning director after a replacement plan has been approved and recorded.
Violations & Fines
Leasing a parcel for a tiny house or tiny home with wheels without an approved binding site plan falls outside the land-division process Franklin County Code § 16.36.020(B) authorizes. An application missing the required Benton-Franklin Health District approval or licensed survey can be returned for modification or denied under § 16.36.080(A), and an existing binding site plan can only be altered or vacated through the same review procedure.
Frequently Asked Questions
Can I put a tiny home on wheels on my property in unincorporated Franklin County?
What does a binding site plan for a tiny home lot require?
Does the tiny home lot also have to meet mobile home park rules?
Sources & Official References
Other rules in Franklin County
Compare Franklin County to another location·View the Washington accessory structures overview
See something wrong?
Help us keep this page accurate. If you notice an error or outdated information, let us know.