Guide
HB 1337 explained for Spokane homeowners
Washington passed HB 1337 in 2023 to make accessory dwelling units easier to build statewide. Here is what it changed in plain language, what it means for Spokane-area lots, and where the local details still need to be confirmed.
What HB 1337 is
HB 1337 is a 2023 Washington law that directs many Growth Management Act cities and counties to update their ADU rules so that accessory dwelling units are easier to build. It works alongside the Growth Management Act in RCW 36.70A. The goal is more housing options on existing residential lots.
What it is understood to change
The law addresses several areas. Because the exact thresholds and how each local jurisdiction adopts them carry real consequences, the specific figures below are flagged for verification against the statute and the Department of Commerce guidance.
- How many ADUs are allowed: [VERIFY: operator to confirm the number of ADUs per lot HB 1337 requires covered jurisdictions to allow from https://app.leg.wa.gov (HB 1337 text and RCW 36.70A)]
- Owner-occupancy: [VERIFY: operator to confirm the extent to which HB 1337 limits owner-occupancy requirements from https://app.leg.wa.gov (HB 1337 text and RCW 36.70A)]
- Parking near transit: [VERIFY: operator to confirm the limits HB 1337 places on ADU parking requirements near major transit from https://app.leg.wa.gov (HB 1337 text and RCW 36.70A)]
- Minimum size allowance: [VERIFY: operator to confirm any minimum ADU size jurisdictions must allow under HB 1337 from https://app.leg.wa.gov (HB 1337 text and RCW 36.70A)]
The compliance timeline
HB 1337 set a timeline for jurisdictions to adopt compliant ADU rules. The reported Spokane-area compliance date should be confirmed, along with whether each local jurisdiction has fully adopted its updated code.
- Compliance date and current adoption status: [VERIFY: operator to confirm the HB 1337 compliance deadline and whether the City of Spokane, Spokane County, and Spokane Valley have adopted compliant ADU codes from https://www.commerce.wa.gov (WA Department of Commerce ADU guidance)]
What it means for your lot
If you read an older Spokane ADU document that lists a single-ADU-per-lot limit, an owner-occupancy requirement, or strict parking minimums, treat those as possibly outdated. The current rule is whatever your jurisdiction has adopted to comply with HB 1337. Check your jurisdiction page, and confirm with the jurisdiction before you plan around any specific number.
Where local details are still being confirmed
State law sets the floor, but each city and county writes the local code that a permit is actually reviewed against. That is why every jurisdiction-specific figure on this site is verified against the local source or flagged. We would rather flag an item than publish a number that is out of date.
HB 1337 questions
- What is HB 1337?
- HB 1337 is a Washington state law passed in 2023 that addresses accessory dwelling units. It directs many Growth Management Act cities and counties to update their local ADU regulations, with changes to how ADUs are allowed, owner-occupancy requirements, and parking near major transit.
- Does HB 1337 apply in the Spokane area?
- Spokane is a Growth Management Act jurisdiction in an Urban Growth Area, so HB 1337 applies. How each local jurisdiction implements the law can vary, so confirm the current adopted rules for the City of Spokane, Spokane County, or Spokane Valley.
- Did HB 1337 remove owner-occupancy requirements?
- HB 1337 limits owner-occupancy requirements for ADUs in covered jurisdictions, so older owner-occupancy language may no longer apply. Confirm the current rule for your jurisdiction before relying on it.
References and primary sources
Regulatory and fee specifics on this page should be confirmed against the current primary sources below. Items marked VERIFY are pending operator confirmation before promotion.
- Washington HB 1337 and RCW 36.70A (app.leg.wa.gov) The statute text and the Growth Management Act.
- WA Department of Commerce ADU guidance (commerce.wa.gov) State guidance on ADU rules.
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