Herriman City has become one of the first communities in Utah to adopt a new Detached Accessory Dwelling Unit (DADU), or backyard cottage, ordinance following the passage of Senate Bill 284 during the 2026 Legislative Session. The ordinance establishes a local framework for homeowners interested in building backyard homes while complying with the new statewide standards created by the Legislature.

WALC appreciates the thoughtful work of Herriman's elected officials, planning staff, and Planning Commission throughout this process. The city's discussions reflected a genuine effort to balance neighborhood concerns with the need for more housing options, resulting in several meaningful policy improvements.

One of the ordinance's most significant achievements is the decision to allow DADUs on residential lots as small as 10,000 square feet. While Senate Bill 284 established an 11,000-square-foot threshold for statewide implementation, Herriman chose to modestly expand eligibility by lowering that requirement. The city also committed to tracking inquiries from homeowners on smaller lots so future policymakers will have real-world data to evaluate whether additional reforms are warranted.

The adopted ordinance represents meaningful progress, though several opportunities remain for future improvements. Earlier in the process, planning staff recommended allowing DADUs on lots as small as 6,000 square feet, matching the city's existing standard for internal ADUs. The Planning Commission ultimately recommended a 7,000-square-foot minimum before the City Council settled on 10,000 square feet. As Herriman gains experience with its new ordinance, this issue may be worth revisiting to expand housing opportunities for more homeowners.

The City Council also chose not to allow homeowners to have both an internal ADU and a detached ADU on the same property, requiring homeowners to choose one housing option or the other. This differs from the recommendation made by the Planning Commission, which supported allowing both types of ADUs on the same lot as long as all other development standards were satisfied. Allowing both an internal and detached ADU can create additional housing opportunities while still maintaining appropriate neighborhood standards.

Finally, Herriman adopted the off-street parking requirements established in Senate Bill 284 rather than pursuing more flexible local standards. While this approach complies with state law, research from successful ADU programs across the country shows that reducing unnecessary parking requirements can lower construction costs, increase the number of eligible properties, and make backyard homes more practical for homeowners to build.

Overall, Herriman's ordinance represents an important step forward in implementing Senate Bill 284 and expanding housing choice within the community. While WALC believes additional opportunities exist to make DADUs more accessible over time, the ordinance provides a solid foundation that will allow homeowners to begin creating gentle, neighborhood-scale housing in existing neighborhoods. As cities across Utah continue implementing SB 284, Herriman's experience will provide valuable lessons for communities working to expand housing opportunities while preserving neighborhood character.