HB 1010
In CommitteeHouse
Rural area ADUs
Authorizing accessory dwelling units in rural areas.
This status may be delayed. See Action History below for the latest updates.
How does a bill become law?
- Introduced: The bill is filed and assigned a number.
- Committee: A subject-matter committee holds hearings, takes public testimony, and decides whether to advance the bill.
- Floor Vote: The full chamber (House or Senate) debates and votes on the bill.
- Opposite Chamber: The bill repeats the committee and floor vote process in the other chamber.
- Governor: The Governor reviews the bill and decides whether to sign or veto it.
- Signed: The bill has been signed into law.
AI Analysis
This bill expands housing options in rural Washington by allowing counties to permit detached accessory dwelling units (like backyard cottages) on rural parcels, even if local rules currently ban them—provided strict rules about water, sewer, size, and design are followed. It also updates planning laws to ensure rural ADUs are formally allowed in official plans and excludes their population from growth targets.
- Allows counties to authorize detached accessory dwelling units (ADUs) in rural areas—even if local plans or policies otherwise prohibit them—subject to strict requirements.
- Limits each parcel to one ADU (attached or detached), with a maximum floor area of 1,296 square feet (or less if the county’s limit for attached ADUs is smaller).
- Requires proof that water supply is available and sustainable: no use of closed water sources, water must be part of the primary dwelling’s water right, and all withdrawals must be metered.
- Mandates that sewage/septic systems can handle added demand, including a pre-permit inspection if connecting to an existing system.
- Prohibits ADUs from encroaching on critical area buffers, agricultural or forestland, and requires compatibility with the primary dwelling’s appearance and shared driveway.
- Requires counties and cities to update their comprehensive plans and countywide planning policies at the next scheduled revision to formally allow rural detached ADUs.
- Excludes population growth from compliant rural ADUs when assessing whether a county is meeting its rural or urban growth targets.
Who is affected
- Rural property owners — Property owners in rural areas gain the option to build a second, detached home (like a backyard cottage) on their land, potentially generating rental income or housing for family members, subject to specific rules.
- County and city governments — Local governments (counties and cities) must update their planning policies and zoning rules to allow detached accessory dwelling units in rural areas, and must ensure water, sewer, and critical area protections are addressed.
- Rural residents seeking affordable housing — Low- and moderate-income households may benefit from increased access to affordable housing options in rural communities where larger-scale development is not feasible.
- Water resource agencies — Water resource managers and agencies gain clearer authority to regulate water use for new dwellings, especially to prevent use of closed water sources and ensure metering.
Pro/Con Analysis
Stronger case for benefits
Potential Benefits (5)
Authorizes counties to permit detached ADUs in rural areas *despite local prohibitions*, significantly expanding housing supply where large-scale development is infeasible—this directly benefits low- and moderate-income households seeking affordable, small-scale housing options in underserved rural communities.
HousingPeopleRef: Sec. 2(1), Sec. 2(4)Caps ADU size at 1,296 sq ft (or local attached-ADU limit), making units more affordable to construct than full subdivisions—low-income families, seniors, or renters can access smaller, lower-cost housing without requiring large capital investments or complex permitting.
HousingPeopleRef: Sec. 2(1)(a), (e)Requires metered water use and septic system capacity verification, promoting sustainable resource management and protecting groundwater—benefits rural communities reliant on aquifers and surface water by preventing overuse and contamination from unregulated development.
EnvironmentPeopleRef: Sec. 2(1)(b)(iii), (d)(i)Prohibits ADUs from encroaching on agricultural/forestland buffers or enabling subdivision to circumvent rules—helps preserve working lands and critical habitats, supporting long-term rural economic resilience and ecosystem services that benefit all residents.
EnvironmentLean peopleRef: Sec. 2(1)(h), (i)Excludes compliant rural ADU population from growth targets—reduces pressure on counties to approve large subdivisions or infrastructure expansions, allowing rural communities to grow incrementally without sacrificing rural character or overburdening limited public services.
Local GovernmentPeopleRef: Sec. 2(4)
Potential Concerns (5)
Mandates water use restrictions (e.g., no use of closed water sources, water must be part of primary dwelling’s water right, metering required) may prevent some rural property owners from building ADUs if they lack existing water rights or infrastructure, disproportionately affecting low-income owners who cannot afford to purchase or share water rights.
EnvironmentPeopleRef: Sec. 2(1)(b)(ii), (c)Requires pre-permit inspection of septic systems by a *licensed contractor*, which adds cost and administrative burden; low-income or elderly property owners may be unable to afford inspections or system upgrades, effectively blocking access to the ADU option despite the policy intent.
Public SafetyPeopleRef: Sec. 2(1)(d)(ii)The 1,296 sq ft cap and design requirements (e.g., matching primary dwelling’s roof form, shared driveway) limit affordability and flexibility—many low-income households seeking ADUs for rental income or multigenerational housing may find the units still too expensive to build or too small to meet needs, especially in areas where land is scarce or soil conditions require costly site prep.
HousingLean peopleRef: Sec. 2(1)(e), (f), (g)Prohibits parcel subdivision to avoid ADU limits, which may prevent owners from legally splitting land to create truly independent housing units—limiting options for heirs or low-income buyers who might otherwise benefit from subdivided parcels, especially in high-demand rural counties.
HousingLean peopleRef: Sec. 2(1)(i)Requires counties and cities to update comprehensive plans and countywide policies at next scheduled revision (often 10 years away), delaying implementation and creating uncertainty—smaller jurisdictions with limited staff may struggle to prioritize this update, slowing rollout of the policy’s benefits.
Local GovernmentLean peopleRef: Sec. 2(3), Sec. 6(8)
Who Is Most Affected
Rural property owners with existing water rights and capital to cover inspections and construction may benefit significantly—especially those seeking rental income or housing for adult children. However, low-income owners, seniors on fixed incomes, or those without water rights may be excluded due to cost and regulatory barriers.
Counties and cities gain authority to override local bans on rural ADUs but must update comprehensive plans and ensure water/septic compliance—smaller jurisdictions may face staffing and technical challenges, while larger counties may benefit from reduced pressure on urban housing markets.
Low- and moderate-income rural households are the primary intended beneficiaries—ADUs offer affordable, small-scale housing where mobile homes or rentals are scarce. However, high upfront costs (inspections, construction) and water/septic requirements may limit actual access for the most vulnerable.
Water resource agencies gain clearer authority to enforce metering and prevent use of closed water sources—this strengthens their regulatory role and helps protect groundwater, but enforcement capacity may be limited in rural areas with few staff.
Agricultural and forest landowners benefit from protections against ADU encroachment on critical buffers and working lands—this preserves land value and long-term productivity, though some may lose flexibility to diversify land use.