Washington state lawmakers are weighing a plan that could turn ordinary driveways into legal long-term homes, by allowing people to live year-round in RVs or tiny houses parked in someone else’s backyard or driveway. Reintroduced this session as HB 1443, the proposal would require cities and counties inside urban growth areas to permit at least one mobile dwelling on lots that already have a house, with some versions of the bill allowing up to two. Backers frame it as a fast, low-cost way to add housing, while critics warn it could dump new enforcement headaches on local governments and raise health and safety concerns.
As reported by KUOW, the idea is the focus of the station’s Booming podcast and related coverage, which asks whether legalizing backyard mobile dwellings would put a real dent in Washington’s housing shortage. KUOW’s Feb. 11, 2026, reporting highlighted families and caretakers who have turned to RVs or tiny houses to stay housed in spite of local restrictions and the threat of enforcement.
According to the House bill report, the legislation defines “mobile dwellings” to include travel trailers, fifth-wheel trailers, truck campers and tiny houses on wheels. Placement would be limited to lots that already have a primary residence and that lie inside urban growth areas. The bill would require standard permitting for new utility hookups, including electricity, potable water and sewer cleanouts, while generally prohibiting local governments from requiring inspections of the units themselves.
Supporters Say It Is Practical, Cities Worry
Housing advocates and some tiny-home builders say MDUs are a fast, affordable option that could free up traditional rentals and help caregivers and seniors stay close to family, according to the Sightline Institute. The Association of Washington Cities has pushed back, arguing that the bill would restrict local tools to ensure habitability, inspections and tenant protections and, in the group’s words, create a regulatory “gray area” that is difficult to manage. The association has also zeroed in on amendments that link the policy to budget funding, a detail cities are watching closely.
How Seattle Treats Tiny Homes Today
Seattle’s permitting office currently treats tiny houses on wheels like camper trailers and says residents cannot live full-time in a wheeled tiny house or RV on a residential lot inside city limits. Tiny houses on foundations are treated instead as detached accessory dwelling units, or DADUs. The city’s ADU program has expanded legal backyard options for homeowners, but those routes generally require a permanent foundation and full building-code compliance, according to Seattle’s Department of Construction and Inspections.
The scale of the problem helps explain the renewed push. A 2024 survey found more than 22,000 Washingtonians living in moveable shelters, a number advocates say has roughly tripled over the last decade and that makes MDUs one of the fastest-growing housing types in the state, according to the Sightline Institute. Supporters argue that legal utility hookups and straightforward permitting would improve safety and stability. Critics respond that the bill’s narrow inspection language leaves too many unanswered questions about who is responsible for making sure living conditions meet basic standards.
Where The Bill Stands
HB 1443 cleared House committees in 2025 but never reached a floor vote. Sponsors brought key elements back for the 2026 session and adopted several amendments on unit limits and funding contingencies, according to the official bill history and related reporting. Local outlets tracking Olympia say lawmakers are likely to debate whether to tie the policy to specific budget resources or to add clearer inspection rules and tenant-protection guardrails as the measure moves through committees.
If HB 1443 becomes law, property owners and renters in Seattle could see driveways and backyards converted into long-term living space, and cities would have to quickly rebuild permitting systems to manage hookups, waste, and safety. For now, advocates, builders, and city officials are watching Olympia and bracing for a test of whether the state’s next wave of housing will roll in on wheels or stall out in code disputes.
