Background: Binding Site Plan. The state subdivision law governs the manner in which cities and counties administer the division of land into parcels for the purpose of sale, lease, or other transfers of ownership. The subdivision law is intended to prevent overcrowding of land, reduce congestion on streets and highways, and provide adequate water, sewerage, and other infrastructure to property, among other objectives.

A city, town, or county may adopt by ordinance procedures for the divisions of land by use of a binding site plan as an alternative to the state subdivision law. The use of a binding site plan ordinance is limited to only a few circumstances, including divisions of property by lease where no residential structures other than mobile homes or trailers will be placed on the land. The ordinance must provide for the alteration or vacation of the binding site plan, and may provide for the administrative approval of the binding site plan.

Local Regulation of Recreational Vehicles. Cities and towns are prohibited from adopting local ordinances that prevent the entry or require the removal of a recreational vehicle used as a primary residence in a manufactured/mobile home community. However, local ordinances may require that, in such communities, the recreational vehicle must contain at least one internal toilet and at least one internal shower or the community must provide for the toilets and showers.

State Building Code. The State Building Code establishes minimum performance standards and requirements for construction and construction materials in the state, consistent with accepted standards of engineering, fire, and life safety. The State Building Code comprises a number of model codes and standards, developed and published by international and national organizations, which are adopted by reference in the State Building Code Act (Act). Model codes and standards adopted in the Act include the International Building Code, the International Residential Code, and the Uniform Plumbing Code Standards.

The State Building Code Council (Council) is responsible for adopting, amending, and maintaining the model codes and standards adopted by reference in the Act. Amendments to the model codes and standards adopted by the Council are codified in the Washington Administrative Code. The Council reviews updated editions of each model code and standard every three years.

Tiny House Building Codes. The International Residential Code Appendix Q applies to tiny houses used as single dwelling units and modifies various requirements in the International Residential Code as it applies to houses that are 400 square feet in area or less, with specific provisions addressing compact stairs, including handrails and headroom, ladders, reduced ceiling heights in lofts, and guard and emergency escapes with certain rescue opening requirements.

Factory Built Housing. The Department of Labor and Industries (L&I) regulates factory assembled structures, which include manufactured and mobile homes, recreational vehicles, and factory-built housing and commercial structures. Factory-built housing is a structure designed primarily for human occupancy, other than a manufactured or mobile home, that is substantially or entirely prefabricated or assembled at a place other than a building site. Factory-built housing may not be installed in the state unless it is approved by and bears an insignia of approval from L&I.

Manufactured/Mobile Home Landlord-Tenant Act. The Manufactured/Mobile Home Landlord-Tenant Act (MHLTA) governs the legal rights, remedies, and obligations arising from any rental agreement between a landlord and a tenant regarding a lot within a mobile home park or manufactured housing community where the tenant has no ownership interest in the property or in the association which owns the property.

Summary: Cities and towns may adopt ordinances regulating the creation of tiny house communities, including through use of the binding site plan method.

Cities and towns may not adopt ordinances that prevent entry or require removal of a tiny house with wheels used as a primary residence in a manufactured/mobile home community, with the exception that ordinances may require that tiny houses with wheels contain at least one internal toilet and one internal shower unless the community provides showers and toilets.

The owner of land on which a tiny house community is located must make reasonable accommodation for utility hookups for water, power, and sewer services in compliance with the MHLTA. Tenants of tiny house communities are entitled to all rights and subject to all duties and penalties under the MHLTA.

Tiny house community is defined as real property rented or held out for rent to others for the placement of tiny houses with wheels or tiny houses using the binding site plan method. Tiny house and tiny house with wheels are defined as a dwelling to be used as permanent housing with permanent provisions for living, sleeping, eating, cooking, and sanitation built in accordance with the state building code. Factory-built tiny houses and tiny houses with wheels are subject to factory-built housing standards and rules administered by L&I.

The Council must adopt building code standards specific for tiny houses by December 31, 2019. Appendix Q of the International Residential Code is recognized by the Legislature as a potential basis for the adoption of new building code standards for tiny houses.

Schools and training programs for students may contract with community service and nonprofit organizations to build tiny houses for low-income housing, without regard to competitive bidding laws for public works, if the students participating in the building of the tiny houses are in:

training in a community and technical college construction or construction management program;
a career and technical education program;
a state recognized apprenticeship preparation program; or
training under a construction career exploration program for high school students administered by a nonprofit organization.

Senate	44	2
House	95	0	(House amended)
Senate	41	1	(Senate concurred)