ADU rules by zoning district
Setbacks for a detached ADU, the size limit and maximum lot coverage, from the published code (Grand Junction Municipal Code Title 21 (Zoning & Development Code, Ord. 5190 eff. 12/20/2023) as hosted on ecode360 (official host; codepublishing.com redirects there). ADU section 21.04.040 history runs through Ord. 5320 (5/20/2026); Ch. 21.03 residential districts through Ord. 5279 (10/1/2025).). The lot check applies the row for your parcel’s district.
| District | ADU allowed | Front | Side | Rear | Lot coverage |
|---|---|---|---|---|---|
| R-R Residential - Rural | Yes | 25 ft | 50 ft | 50 ft | 5% |
| R-ER Residential - Estate Retired | Yes | 25 ft | 5 ft | 10 ft | 15% |
| R-1R Residential 1 Retired | Yes | 25 ft | 3 ft | 10 ft | 20% |
| R-2R Residential 2 Retired | Yes | 25 ft | 3 ft | 5 ft | 30% |
| RL-4 Residential Low 4 | Yes | 25 ft | 3 ft | 5 ft | 50% |
| RL-5 Residential Low 5 | Yes | 25 ft | 3 ft | 5 ft | 60% |
| RM-8 Residential Medium 8 | Yes | 25 ft | 3 ft | 5 ft | 75% |
| RM-12 Residential Medium 12 | Yes | 25 ft | 3 ft | 5 ft | 75% |
| RH-16 Residential High 16 | Yes | 25 ft | 3 ft | 5 ft | 75% |
| RH-24 Residential High 24 | Yes | 25 ft | 3 ft | 5 ft | 80% |
Size limit: 900 sq ft of habitable space ); not gross floor area.
Sources: ecode360.com · ecode360.com · ecode360.com · ecode360.com
Questions people ask
Are ADUs allowed in Grand Junction?
Yes. The City of Grand Junction allows a detached ADU in all ten of its residential districts (R-R, R-ER, R-1R, R-2R, RL-4, RL-5, RM-8, RM-12, RH-16 and RH-24). One detached ADU is allowed per lot.
How big can an ADU be in Grand Junction?
Up to 900 square feet of habitable space inside city limits. Mechanical rooms, unconditioned space and stairwells don’t count toward that figure, and ADUs are exempt from the cap that limits other accessory buildings to 75% of the house.
What are the ADU setbacks in Grand Junction?
A detached ADU follows the accessory-building setbacks for its district: 25 feet from the front in every district, and in most districts 3 feet from the side lot line and 5 feet from the rear. Large-lot districts are larger (R-R is 50 feet). The table below lists every district.
Does an ADU in Grand Junction need parking?
The current code doesn’t list a parking requirement for ADUs. Older city guidance mentioned one space; that guidance predates the current code.
Is my lot in the city or the county?
A Grand Junction mailing address doesn’t settle it — areas like the Redlands and Orchard Mesa include both city and county parcels. The lot check reads the county parcel record and tells you which rules apply.