Weber County · about 9,200

Riverdale

Confirm detached with the city

Internal accessory dwellings follow state law. We did not find a 2026 detached ordinance with a recorded vote. State law now requires a permitted detached unit on a lot of 11,000 square feet or larger with a house. Many Riverdale lots are tighter than that — the first question is whether the building fits.

Internal ADU: Permitted in most residential zones under House Bill 82.
Detached ADU: Confirm the local table. On a qualifying lot the use is permitted under state law, not conditional.
Lot: 11,000 square feet is the statewide detached floor, now in effect. The city may allow a smaller lot.
Size: Per ordinance. The city may limit size and may require that the unit not exceed the house.
Parking: Per ordinance, and not more than the state cap: one stall under 650 square feet, two at 650 and above.
Owner occupancy: Owner occupancy is typical. Confirm.
Rental: Long-term occupancy is the usual rule.
Design: Setbacks, height, and coverage remain local.

Notes

A parcel map and a call to Riverdale planning will tell you more than a generic ADU article.

Statewide floor

Senate Bill 284, Utah Code §10-21-304, has been in effect since October 1, 2026. Every city on this list must allow a detached ADU as a permitted use — not a conditional use — on a lot of 11,000 square feet or larger that already has a permitted single-family house. A city may also allow one on a smaller lot. It may still set size, height, coverage, setbacks, and owner occupancy, and it may require that the unit not be larger than the house, not sit in the front yard, and not be rented for fewer than 90 days. Parking may not exceed one stall under 650 square feet, or two stalls at 650 square feet and above. A printed ban, or a conditional-use requirement, on a qualifying lot conflicts with the statute even if the code book is late. Confirm the city’s ordinance before anyone draws.

Inquire about a lot in Riverdale

We verify the ordinance that applies to your parcel as part of feasibility. Riverdale City