PDFWAC 296-150I-0300
Installation standards for manufactured homes.
(1) The director of labor and industries is responsible for establishing uniform standards and requirements for the installation of manufactured homes within the state.
(2) Local jurisdictions may adopt additional installation requirements only for those installation situations not covered by federal standards. For example, local jurisdictions may impose fire sprinkler requirements, noise control construction ordinances, prescribe the frost depth and soil bearing capacity at the installation site, and adopt requirements to protect manufactured homes in hazardous areas (see WAC 296-150I-0340).
Also, local jurisdictions may impose their requirements for snow loads as long as all structures within their jurisdiction are required to comply with the same standard and provided those installing the manufactured home are given options in satisfying that standard. Such an option might include, but not be limited to, allowing an installer to erect an additional structure, which meets local standards, and protects the manufactured home. For example, an installer could erect a freestanding roof structure over a manufactured home to protect it from local snow loads.
Local jurisdictions may not:
(a) Dictate alternate foundation design and construction when a foundation is built according to either the manufacturer's installation instructions or a design created by an engineer or architect licensed in Washington state.
(b) Impose regulations on smoke detectors and carbon monoxide detectors because they are regulated by federal standards.