Hooper staff recommend raising size threshold for accessory structures, propose ordinance draft to cut hearing load

Amanda, a city planning staff member, told the Hooper City Council that the city has seen dozens of oversized accessory-structure applications in recent years and presented options to reduce the number of conditional-use hearings those projects require.

The proposal grew from city data, Amanda said: in 2023 there were 14 oversized accessory-structure approvals averaging about 3,021 square feet and five oversized structures that included accessory dwelling units (ADUs) averaging about 3,200 square feet; in 2024 there were 12 oversized structures (about 2,500 square feet average) and four oversized-plus-ADU projects averaging about 2,124 square feet; through early 2025 the city had received three oversized-structure applications averaging closer to 3,000 square feet. Amanda said those figures suggested Hooper’s current 2,000-square-foot threshold (for R-1) is below what residents are building and is producing more applications than staff regard as necessary.

“I'm not taking a side here,” Amanda said while presenting the data, describing the numbers and policies used by nearby jurisdictions. She told the commission that three of the four peer cities she contacted use a 25 percent rear-yard limit on accessory structures; in those places the rule either blocks projects over that threshold outright or requires only limited review. Amanda proposed the city could either raise its square-foot thresholds or adopt a percentage-of-rear-yard approach to limit which projects must come to the commission.

Why it matters: raising a threshold or adopting a rear-yard percentage would reduce the number of conditional-use hearings and staff time spent on routine applications, while preserving review for very large or potentially problematic projects. Amanda said the change could reduce the commission’s workload — she estimated it “probably” would reduce the number of applications the commission sees by a noticeable percentage if staff implemented a higher threshold.

Commission members and staff discussed operational details and potential side effects. Amanda and others noted existing zoning maximums in Hooper’s zones (as discussed in the meeting): roughly 1,600 square feet in R-2, 1,800 in R-7.5, and 2,000 in R-1. Amanda said that if the city moved to a 25 percent rear-yard approach, those numbers would be replaced by a lot-size-driven calculation and that she would need to “wrap [her] mind around” some implementation details before drafting language.

ADUs: Amanda also addressed accessory dwelling units. She noted the city’s current ADU maximum (as discussed) of 960 square feet and said staff’s preferred approach was to keep ADUs subject to building permits and existing setback/impervious-surface limits rather than requiring every ADU to come to the planning commission. “I would lean more to just letting the lot size dictate what that size is,” Amanda said in the meeting, explaining that lot-size, setbacks and drainage rules already limit how large an ADU can realistically be.

Pool enclosure and fencing safety: Commissioners raised safety questions about one applicant, Bryce Clark, who proposes an attached accessory building that would contain a swimming pool with bay doors that could be opened for ventilation. Brandon, a staff member, summarized the code requirement the commission is considering: “All gates on deck fences shall be self-closing and fitted with a self-latching device located on the interior side of the gate.” Commissioners asked whether bay doors that open to the outside would create the same hazard as a gate without an automatic latch; Brandon told the commission the structure is an enclosed building and staff were comfortable with the enclosure but that fencing around the pool or property could be required if commissioners preferred. Nathan (Nate), referenced in the discussion as an enforcement or inspection staff member, was identified as the person who would check required clearances such as the three-foot separation from sewer laterals.

Impervious-surface concerns were raised: staff reported a building-inspector check that had placed one property’s impervious surface at about 55 percent and said the lot was “about 10 percent away” from a higher threshold; the commission flagged this as a factor that could limit structure size regardless of a new square-foot or percentage rule.

What the commission directed: commissioners did not adopt a code change at the meeting. Instead, staff were asked to draft ordinance-change options for the commission’s review — either a raised square-foot threshold, a 25 percent rear-yard rule, or a hybrid approach that keeps ADU review administrative while sending larger accessory-structure proposals to the commission. Amanda said she would prepare language and return for the commission to fine-tune before sending anything to City Council.

Next steps: staff will prepare ordinance-change drafts and additional implementation detail (including how the rear-yard percentage would be calculated and how impervious-surface limits are applied) for a future commission meeting; the commission agreed it would consider whether to recommend the drafts to the City Council for adoption.