Commission reviews accessory‑structure standards, driveways and ADUs amid stormwater concerns

Planning staff told the commission that existing code exempts driveways and drive‑turnarounds from impervious‑coverage calculations, and commissioners said driveway expansion, cumulative accessory additions, and phased permitting are increasingly affecting stormwater and neighborhood character. Commissioners discussed: (1) calculating driveways and turnarounds into impervious coverage or defining thresholds that would bring larger proposals to the commission; (2) treating accessory structures and attached decks consistently for footprint and stormwater review; (3) addressing phased projects that add multiple accessory items over time to avoid piecemeal circumvention of caps; (4) making ADU approvals contingent on driveway, parking and stormwater feasibility; (5) treating pools as potentially higher‑impact accessories warranting review because of location and discharge; and (6) permitting pervious pavement, pavers or two‑track drive options instead of limiting “hard surface” materials to only concrete and asphalt. Staff said the code currently lists concrete and asphalt as acceptable parking/hard surfaces and that the commission has the discretion to require additional design or stormwater mitigation through special permits. Commissioners suggested updating the code to allow pervious alternatives and clearer cumulative caps on accessory square footage so staff can uniformly apply stormwater standards during plan review. No formal code change was adopted on Sept. 4; staff will return with proposed language and examples.