VHH Policy Advocacy: Big Ideas, Real Impact

Mobile Dwelling Units

Take care of our community now, build for the future.

Vashon is losing workers, seniors, caregivers and families because housing has become scarce and unaffordable. Permanent affordable housing remains the long-term answer, but it takes years to build.

Vashon HouseHold has proposed to King County development of a Mobile Dwelling Unit, or “MDU” pilot that would allow a small number of movable homes on private property only through an annual permit, an approved sanitation plan, fire and safety standards, setbacks, affordability limits and enforcement. It is a practical way to test whether safe mobile housing can help people remain on the island without compromising public health or community standards.

Informal vehicle habitation already occurs. A permit process creates sanitation review, clear responsibility, safeguards, complaint response, and the ability to correct or revoke noncompliant sites. A pilot like we propose allows King County to collect data, measure complaints and compliance, and decide whether the approach should continue, change or end. Read more about Oregon’s work with MDUs here.

MDU FAQs

  • In this context, a Mobile Dwelling Unit is a movable structure intended for human habitation, such as an RV, travel trailer, park-model home or tiny house on wheels. It would remain movable and would be located on private property under a County permit.

  • No. Permanent affordable rental and homeownership opportunities remain the long-term goal. Mobile dwellings are one near-term tool within a broader strategy that includes development, acquisition, ADUs, gentle infill and policy reform.

    VHH will request documentation in order to determine income qualifications before you can enter into a contract negotiation with a seller. Most lenders will require this information as well, and VHH can provide you a copy of this income qualification document.

  • No. The draft materials contemplate a small number of units per qualifying residential parcel, with no more than two in the current working framework and additional limits based on acreage and site conditions.

    Sunflower: Resale is subject to an 80% median income restriction cap. Currently the maximum resale price is approximately $190,000 for one-bedroom home with a loft room. All 14 Sunflower homes fall in this category.

    Roseballen: Resale is subject to an 80% median income restriction cap. Currently the maximum resale price is approximately $230,000 for two, three, and four-bedroom homes.  All 19 Roseballen homes fall in this category.

    Vashon Co-Housing:  Price is only limited by what a buyer at the 80% median income can afford. There are only five homes governed by these restrictions.  All other Co-Housing homes are market rate housing. This project has the fewest resale restrictions.  Co-Housing does require an interview about co-housing participation and expectations, as this is a more intentional community.

  • A sanitation plan would be reviewed before a permit is issued. Proposed options include an approved connection to an existing septic or sewer system, or certified composting and greywater systems approved by Public Health. Potable water would come from an approved residential connection or certified storage and delivery system. Direct discharge to soil or surface water would be prohibited.

  • The working proposal requires smoke and carbon-monoxide detectors, safe egress, emergency access, compliant propane systems and approved electrical connections. Generators would be restricted to emergency use.

  • No. The draft ordinance prohibits nightly and short-term rental use. Commercial misuse would be grounds for permit revocation.

  • The draft framework includes existing, standard setbacks from wells and surface water and prohibits siting in designated critical areas. Exact distances and review procedures would be finalized with King County and Public Health in compliance with existing statute.

  • No. The working framework includes an affordability cap tied to households at or below 80 percent of Area Median Income and requires financial terms to be documented in a host-resident agreement. The final formula will need to be confirmed during policy development.

  • Some people already live informally in RVs or other movable dwellings because they have few alternatives. A legal permit creates an accountable property owner, sanitation review, safety expectations, documentation, a complaint pathway and the ability to require correction. Regulation makes the situation more visible and manageable, not less.

Affordable ADU Tax Breaks

More avenues for revenue and tax breaks for the folks who need it most.

Washington law now authorizes King County to exempt the value of qualifying accessory dwelling units (ADUs) from property taxation when they are rented to low-income households. The policy concept therefore no longer needs to be invented. The urgent work is to determine how King County can interpret, design, fund, administer, and evaluate a legally sound program under RCW 84.36.400(2).

The statutory authority is only a starting point. King County is not yet administratively positioned to enact the exemption. Before the County Council can adopt a workable program and the Executive, Assessor, and other partners can implement it, substantial legal, valuation, fiscal, operational, and interagency questions must be resolved. Some may be answerable through county program design; others may require Department of Revenue guidance, formal legal interpretation, or legislative clarification.

Vashon HouseHold is working in coalition with councilmember offices and communities in King County to help move affordable ADU tax breaks from idea to implementation.

Smart Zoning. Now.

Sprawl won’t fix the problem. Urban density isn’t right for Vashon. There’s a third way.

Vashon HouseHold advocates for immediate zoning and policy updates that support small-scale, high-impact housing models. We can’t wait another 10 years for the Comp Plan to roll around again. The housing crisis is happening now, and we need gentle infill solutions now.

  • Retain affordable density bonuses in the town core

  • Revise zoning and code to allow clustered, higher density “cottage homes” on appropriate acreage

  • Allow and expedite rolling-basis spot rezones of industrial and commercial properties when paired with permanently affordable development.

Fix the Policy Loopholes

20th century policies are failing us. It’s time to adapt.

Vashon does not need massive towers or sprawl to respond to the housing crisis. We need island-appropriate solutions that add homes thoughtfully—while protecting environmental values and community character. We need new policies for new problems:

  • Manage the growth of vacation rentals on Vashon, including adding potential limits, fees, or taxation mechanisms to protect year-round housing stock while preserving homeowner access to revenue and generate dedicated revenue for community benefit.

  • Follow the lead of the Federal government and revise code to streamline builds using modern, modular construction methods.

  • Invest in modernizing and expediting permitting processes and people. Vashon isn’t a gated carbon offset for the County to protect from all development. It’s a living, breathing community that needs the ability to implement the right answers, right now. We cannot address this problem if it takes years and a small fortune to permit housing.