Coupeville council debates state 'middle housing' mandates, ADU limits and sets workshop

Planning Director Joshua told the Coupeville Town Council on Feb. 11 that recent Washington state laws require municipalities to revise local development rules to increase residential options, and outlined a proposed local package that would allow duplexes, triplexes and two accessory dwelling units (ADUs) on parcels now zoned for single-family housing.

The presentation traced three state measures Joshua identified as relevant — ESSB 5258, House Bill 1110 and House Bill 1337 — and summarized how the bills together affect small cities. “The state statute requires all fully planning jurisdictions … to allow two accessory dwelling units on parcels with a single-family residence on them,” Joshua said, and noted the state also set a tier system that drives how much middle housing the locality must allow.

The council’s discussion focused on how the new rules would interact with Coupeville’s status as a municipality inside a national historical reserve and on practical concerns about infrastructure and neighborhood character. Joshua noted an exemption in RCW language for cities contained within a national historical reserve that allows a jurisdiction to limit density if the limits are “necessary and appropriate to protect physical and cultural historical integrity.” He said the exemption exists but would require the town to document and defend any restrictions to the state.

Council members asked about lot coverage, parking requirements, stormwater and water-system capacity. Joshua said current development standards — setbacks, lot-coverage limits and parking rules — would still apply and that the town’s water system and equivalent residential unit (ERU) accounting already govern how many new connections the system can accept. He added the town has a $35,000 Department of Commerce grant to help write code updates and that the municipal deadline to use some grant funds is the end of the state fiscal year (June 2025).

Several council members voiced caution about adopting the full set of state-mandated changes immediately. Concerns included the potential loss of local control, damage to the town’s historic character, narrow streets and the difficulty of reversing statewide mandates later. Joshua said the state provides model ordinance language and that if the town does not adopt a local ordinance that meets the state standard, model provisions can supersede local code.

Rather than taking immediate regulatory action, the council agreed to schedule a separate, in-depth workshop to review proposed code language, design guidelines and unit-lot subdivision rules; Joshua said he would propose dates and materials for that session. The council also discussed narrower alternatives — for example, allowing middle-housing forms (duplexes and cottage-style units) while limiting detached ADU form or restricting ADU form through size and attachment requirements — and directed staff to explore those options further.

Why it matters: The state laws Joshua summarized are intended to increase housing supply and diversify housing types. For Coupeville, the debate pits state-driven housing-intensification goals against local priorities to protect a national historical reserve, maintain small-town character and manage infrastructure impacts.