Sen. Jeff Wilson speaks on the Senate floor Wednesday as his kit home bill gets a 49-0 vote in the Senate for the third straight time. To see video, click here.

OLYMPIA – A bill that aims to establish kit homes as an affordable housing option in Washington passed the state Senate unanimously for the third time Wednesday.

Sponsor Jeff Wilson, R-Longview, said he hopes the bill will make it across the finish line this year. “Sometimes it takes time to win acceptance for a new idea,” he said. “The good news is that this bill has passed the Senate so many times we can’t call it new anymore.”

Senate Bill 5552 directs the state Building Code Council to develop new rules specifically for kit homes of 800 feet or less. The idea is that standardized kits should undergo design review only once, bypassing the one-by-one reviews required for custom stickbuilt homes.

Wilson said kit homes offer a way to build vitally needed housing at low cost. Kits start at less than $10,000, typically using prefabricated parts that can be assembled by an ambitious do-it-yourselfer. Wilson said the kits are well-suited for use as accessory dwelling units (ADUs) or tiny homes.

In remarks on the Senate floor, Wilson reminded lawmakers that kit homes once were commonplace, and a century ago it was possible to order them through the Sears catalog. In the present day, he said kit dwellings offer a way to address the state’s shortage of affordable housing. “Let’s get the rules worked out and let the kit homes begin,” he said.

Wilson originally introduced his kit home bill in 2023. The Senate unanimously approved the bill in 2024 and 2025, but both times it died without a vote in the House. The 49-0 vote in the Senate Wednesday sends it to the House again for further consideration.