ADU rules in Cottonwood Heights

Detached ADUs may be allowed as conditional uses in the R-1 (single-family), RR-1 (rural residential), and F-1 (foothill residential) zones; requires planning commission approval following a public hearing. Must be a permanent structure in the rear yard, set back at least 6 feet from the primary structure, and meet accessory building standards for the zone.

Internal ADUs are permitted uses in R-1, RR-1, and F-1 zones on owner-occupied lots larger than 6,000 sq ft; prohibited on lots of 6,000 sq ft or less or where the primary dwelling is served by a failing septic tank. Must be created within the footprint of the primary dwelling and must not change its single-family appearance. Requires an ADU permit with annual renewal.

Internal ADUs must fit within the footprint of the primary dwelling at the time created (§19.75.020 definition). Detached ADUs must meet the underlying zone's accessory building standards for height, lot coverage, rear-yard coverage, and size (§19.75.050); those zone-specific accessory building limits were not extracted in this session.

The record owner must occupy either the primary dwelling or the ADU as their permanent residence and may never receive rent for the owner-occupied unit; owner occupancy is defined as legal residence at the site at least 200 days per calendar year. Proven by notarized affidavit (§19.75.060); ADU use terminates if the owner no longer permanently resides there (§19.75.090).

Tandem parking is prohibited for both types. New front-yard parking spaces are prohibited for detached ADUs (existing driveways excluded). Garage/carport spaces converted to an internal ADU must be replaced.

Internal ADUs are permitted uses (by right, but still require an ADU application, inspection, affidavit, and annual permit renewal). Detached ADUs are conditional uses requiring planning commission approval after a public hearing, also with annual renewal.

'ADUs shall not be used as short-term rentals' (§19.75.050); short-term rental is defined as fewer than 30 consecutive days (§19.75.020). The owner may never receive rent for the unit they occupy.