Ferron planners target ADU, tiny-home and short-term rental rules in code update

Todd Thorn, regional planner with the Southeastern Regional Development Agency (SIRDA), told Ferron’s planning commission on June 26 that the quickest way to respond to housing and tourism pressures is to change the city code before undertaking a full general-plan rewrite. “I think we should update your ordinances first,” Thorn said.

The commission discussed three closely linked topics: accessory dwelling units (ADUs, also called granny flats or IADUs for internal ADUs), the possibility of tiny-home developments, and how to regulate short-term rentals such as Airbnbs. Thorn and multiple commission members said ordinance changes could be limited, short documents intended to give staff and applicants clear, enforceable rules while the city’s full general plan is revised.

Why this matters: Ferron faces local pressure from housing-affordability concerns and growing short-term rental use tied to regional tourism. Commissioners said unclear zoning language—examples included “adequate parking” and inconsistent references to residential in commercial zones—has left enforcement and development review ad hoc. The ordinance approach aims to give staff “teeth” to regulate uses consistently and quickly.

Details from the discussion

- State and building-code context: Thorn said state code already requires communities to allow internal ADUs (IADUs) —basement or interior conversions—though municipalities may adopt reasonable regulating standards. He contrasted that requirement with other ADU controls communities commonly adopt: fixed maximum square footage, lot-size limits and owner-occupancy requirements.

- Size limits and examples: Thorn described two common approaches: limit an ADU to a percentage of the primary dwelling or impose a fixed cap. He said Carbon County’s ordinance uses a 1,000-square-foot cap for ADUs so very large primary houses cannot effectively contain two full homes. He also noted the building code’s threshold for “tiny home” classification (roughly 400 square feet) and that tiny-home regulations are handled differently than ADUs.

- Lot-size and location limits: Communities sometimes restrict ADUs to parcels above a certain size (Thorn said Carbon County used a quarter-acre/12,000-square-foot threshold as an example). Another option discussed was allowing tiny-home clusters only in purpose-built zones so smaller units do not sit next to standard single-family lots.

- Renting and short-term rental limits: Commissioners raised options including (a) requiring an owner to occupy either the primary dwelling or the ADU, (b) allowing only one of the two units to be rented, (c) outright prohibiting ADUs as Airbnbs, or (d) capping the number of short-term rental licenses per capita or per zone. Thorn noted some Utah communities cap STR licenses and operate wait lists when capacity is reached.

- Fire, setbacks and spacing: Commissioners heard that building- and fire-code requirements influence allowable separations and required fire-rating when structures are closer than typical setbacks; a 5-foot setback can trigger fire-rating or other requirements depending on local code.

What will happen next

Thorn said SIRDA will provide short, example ordinances (ADU, tiny-home/small-lot development and Airbnb/STR rules) drawn from nearby rural cities for Ferron staff and the commission to edit. The plan is to draft compact ordinance language (in many cases one to several pages) so the commission can review and take items to public hearing and adoption more quickly than waiting for a full general-plan update.

Ending

Commissioners agreed to begin with ordinance drafts on ADUs, tiny-home approaches and STR rules, then review those drafts at upcoming planning-commission meetings. No formal policy changes were adopted at the June 26 session.