Herriman council continues ADU code amendment, directs staff to return with revisions and impact-fee recommendations

Michael (speaker 4) introduced proposed amendments to Title 10 (land development code) to permit detached accessory dwelling units (ADUs) in single-family zones, summarizing planning commission recommendations and potential state legislative constraints. Key features discussed included allowing detached ADUs citywide for single-family lots, a maximum ADU size of 1,000 square feet, a proposed maximum height of 25 feet, required off-street parking (one additional stall, two stalls if ADU > 650 sq ft), and an initial planning commission recommendation of a 7,000 sq ft minimum lot size.

Council members debated policy choices at length. Some councilmembers (including Jared, speaker 9) favored a "one or the other" approach—allowing either a detached ADU or an internal ADU on a single lot—to reduce parking, access and density impacts. The mayor (speaker 1) proposed raising a working minimum lot size to 10,000 sq ft as an initial policy to limit staff workload and reduce small-lot complications, and several colleagues agreed that the council could revisit the threshold later.

Members also discussed whether a detached ADU could be taller than the primary home (some favored limiting height to the existing dwelling, other staff language allowed 25 ft), setbacks (planning commission recommended mirroring accessory-structure setbacks), metering and utility connections (options for shared or separate meters), impact fees (police, fire, roads) and enforcement concerns including spec-built ADUs marketed as rentals versus owner-occupied ADUs. Staff noted internal ADUs cannot be charged impact fees by statute and recommended caution until the state legislative session completed its current bills.

After discussion, Jared (speaker 9) moved to continue item 9.3 and direct staff to return with the revisions discussed and to include recommendations on impact fees; Teddy (speaker 8) seconded and the motion passed on roll call. Staff will return with a rewritten ordinance informed by council direction and pending state legislation.