Issaquah approves self‑certification for detached accessory dwelling units to speed housing

The Issaquah City Council on July 20 voted to adopt an ordinance allowing licensed architects to self‑certify certain detached accessory dwelling units (DADUs) under the authority of Washington State House Bill 1353, with exclusions for geologically hazardous or steep‑slope sites.

Building Official James Gray explained the program, which is intended to make small, code‑compliant ADUs easier to permit by allowing an architect’s certification to substitute for a full plan review on simple structures. The staff and the Planning, Development & Environment committee recommended the approach over investing in preapproved plan sets, which other cities have found to be underused and difficult to adapt to Issaquah’s hillside constraints.

The ordinance ties size limits to Title 18 and excludes DADUs in mapped geologically hazardous areas that would require significant structural work (retaining walls, piles) because those cases need engineering review beyond the scope of architect self‑certification. The program also anticipates either separate water‑meter connections or use of existing service connections and notes potential complications from sprinkler, meter and connection fees.

Council members praised the change as a practical step to unlock more housing options in Issaquah, with several members saying they expect ADUs to be popular in Old Town and across the city. Council approved the ordinance unanimously; staff noted the statute requires periodic checks and sample inspections to ensure compliance and that architects who fail certification checks can face sanctions under state rules.

Next steps: Staff will implement the self‑certification pathway, develop outreach and guidance for homeowners and architects, and incorporate the program into permit workflows.