Clinton Updates ADU Rules: Earlier Site-Plan Review, Clearer Foundation Standards and a New Yard-Coverage Count

Clinton has updated its rules for accessory dwelling units, the basement apartments, attached suites and backyard cottages often called ADUs. The City Council adopted Ordinance 26-02Z on Aug. 25 by a unanimous roll-call vote, according to the official minutes of that meeting.

What changed

Senior Planner Keaton Jones told the council that after processing internal, attached and detached ADU applications under the old rules, staff found several spots that needed clarifying. The amendments to Section 28-3-27 of city code include:

• A preliminary site-plan review before an ADU application reaches the building-permit stage.
• Clearer foundation requirements for detached ADUs and tiny homes. A unit can be delivered to a site, but it must be permanently set on an approved foundation and meet building codes to count as a dwelling.
• A new definition of “recreational vehicle.”
• Updated parking provisions.
• Adjustments to match current state law.

A new way to count backyard coverage

The biggest practical change involves the 25 percent rear-yard limit. Under the update, patios, driveways, sport courts, structures and other hard surfaces all count toward that 25 percent, rather than an ADU being allowed to take up 25 percent on top of them. City leaders said the change helps keep stormwater on the property. Staff told the council that setbacks and the rule tying ADU size to the main home are usually more limiting than the coverage cap, so the change should rarely block an otherwise workable ADU.

Mayor Marie Dougherty noted the old ordinance also did not allow a tiny home on wheels to serve as an ADU without a permanent foundation, but the wording had not been clear. The Planning Commission reviewed the changes several times and recommended approval.

What it means for residents

If you are thinking about adding an ADU in Clinton, expect an earlier site-plan step and plan your backyard layout with all hard surfaces in mind. Talk with the city’s planning staff before buying a prefabricated unit; the mayor said the city has seen units bought without review that lacked proper certifications.

The council heard one public comment, from a resident finishing an ADU who praised city staff for their help. Find the meeting materials on the Utah Public Notice Website. For more local coverage, visit our Clinton page or news section.