Boise staff recommend code change to permit tiny homes on wheels; council asks for fee and safety details

City planning staff told the Boise City Council the tiny-home-on-wheels (THOW) pilot yielded early evidence that movable tiny homes can provide lower-cost housing options without known health or life-safety failures, and asked whether council wants staff to draft a permanent zoning code change as part of year-1 code updates.

Nikki Olivier Hellingamp, planning staff lead on the pilot, said the 2023 pilot allowed movable tiny homes on trailers—built with standard housing materials, under 400 square feet—to be sited in backyards for 1218 months. The city received 56 applicants and permitted six pilot sites across Boise (two in the North End, two near Broadway and Boise Avenue, one near Orchard and I-84, and one at Maple Grove and McMillan). Staff said tiny-home villages were contemplated but none participated in the pilot.

Staff reported no known health or safety issues to date and said the structures "wintered well." Occupant-reported costs varied: tenants who paid only space fees generally paid $500$650 per month; some sites in Hailey charged up to $800. Renting both space and the tiny home could be about $1,070 per month, which staff said would be affordable for a two-person household at 60% area median income under federal guidelines. Property-owner site setup costs ranged widely, from about $1,500 to $11,000.

Staff proposed several code elements if council wants to proceed: permit THOWs in zones where ADUs are allowed (plus MX-1, -2 and -3), require adherence to zone setbacks and a minimum 6-foot separation from other structures, allow one THOW per property as accessory to the primary residence, require permanent utility connections and high-quality skirting and a flat compacted pad, and consider whether to restrict rentals to long-term (31+ days) as the City of Hailey has done. Staff also noted Hailey's ordinance requires NOAH/ANSI certification standards for THOWs.

Council members pressed staff for details on impact fees (staff said the pilot did not charge impact fees and that, if permitted long term, fees would be assessed on the same basis used for hotel rooms and would likely be lower than those for ADUs because of smaller square footage), utility hookup expectations (staff said permanent connections were proposed for long-term allowance but that pilot participants used a mix of above-ground, freeze-protected hookups and, in some cases, simple plug-in arrangements), and funding or incentive options (state law permits waiving impact fees for deed-restricted affordable housing if the city makes up the fees from the general fund; naturally occurring affordable housing lacks that statutory waiver unless the city provides funding).

Multiple council members signaled support for advancing the proposed ordinance into the March year-1 code updates while asking staff to return with specific fee estimates, utility-connection cost ranges, input from Boise Fire Department on addressing emergency response and addressing neighborhood impacts such as parking. Council members also asked staff to analyze whether the one-per-parcel limit should have parity with any ADU limits that council later sets.