Hooper planners propose changes to accessory dwelling and accessory‑structure rules; commission to review

Hooper City planning staff presented draft amendments to the city’s accessory dwelling unit (ADU) and accessory‑structure rules and asked the Planning Commission for feedback before the city council takes up the ordinance. The draft includes changes to minimum and maximum sizes, lot‑size thresholds by residential zone, and parking requirements for ADUs and detached accessory units.

Staff said the proposal would keep a 400‑square‑foot minimum for accessory dwellings but would cap ADU area as a share of principal‑lot buildable area. Staff discussed a model in which ADUs could be limited to 50 percent of the allowable accessory‑structure square footage, with a conditional‑use option to allow larger units in some cases. Commissioners and staff discussed alternative approaches such as setting a higher fixed maximum in R‑3 zones (for example, 1,800–2,000 square feet) or allowing a higher percentage in specific circumstances so that a 900‑square‑foot ADU could remain possible on typical lots.

The draft also proposes revising lot‑size thresholds for certain zoning categories: staff said a draft would move some R‑2 thresholds to 2,500 square feet, R‑3 to 3,000, and R‑1 to 5,000 (staff characterized these as proposed thresholds for the city’s review). Commissioners asked staff to clarify how those thresholds interact with the ADU percentage caps so that existing applicants would not be unintentionally excluded.

Parking rules were flagged for more work. Current parking requirements were discussed as one parking space per dwelling; staff said the commission had discussed requiring two parking spaces for some ADUs or providing staff discretion during review. Commissioners also asked staff to identify rear‑yard coverage limits, setback and utility separation rules, and enforcement approaches for accessory structures that convert into living units.

Commissioners discussed allowing detached accessory structures while limiting total lot coverage to protect neighboring yards and drainage. Staff noted other cities use rear‑yard‑specific limits to avoid excessive impervious surface in back yards and suggested the commission consider a similar provision.

Staff asked the commission whether R‑3 allowances should increase from a strict 50 percent cap to 75 percent in specific cases; one commissioner suggested 75 percent for R‑3 as a compromise. Staff said they would draft clearer, simpler language for the city council packet and return with model ordinance text showing how percentage caps and fixed maximums would work in each zone.

Ending: Staff will revise the draft language to address parking, percentage caps, rear‑yard coverage and clearer interaction with zone thresholds and will email that revision before the next meeting. No formal vote on ordinance adoption occurred at this meeting.