ADU Rules: Northglenn vs Westminster
How do adu rules rules compare between Northglenn, CO and Westminster, CO?
Northglenn and Westminster have similar restriction levels.
Northglenn, CO
Adams County
Adams County allows one Accessory Dwelling Unit on any legal single-family lot in any zone district under Section 4-03-03-02-01 of the Adams County Development Standards and Regulations. ADUs must be 500-1,500 sq ft (detached cap), max 25 ft tall, with one off-street parking space. There is no owner-occupancy requirement. Adams County aligned its rules in 2025 with Colorado HB24-1152 (effective June 30, 2025) for surrounding subject jurisdictions.
View full Northglenn rules →Westminster, CO
Adams County
Westminster regulates ADUs through local zoning. Colorado HB 24-1152 requires certain municipalities to allow ADUs. Rules vary by city.
View full Westminster rules →Key Facts Comparison
| Fact | Northglenn | Westminster |
|---|---|---|
| Code Section | Adams County Dev. Standards 4-03-03-02-01 | - |
| Min. Size | 500 sq ft | - |
| Max. Size (detached) | 1,500 sq ft | - |
| Max. Height | 25 ft (to roof mid-pitch) | - |
| Owner Occupancy | Not required | - |
| Parking | 1 off-street space | - |
| State Law | Colorado HB24-1152 (eff. 6/30/2025) | HB 24-1152 (2024) |
| Local Rules | - | Vary by city |
| Permit | - | Building permit required |
| HOA | - | May restrict |
Highlighted rows indicate differences between cities.
Northglenn FAQ
Do I have to live on-site to build an ADU in Adams County?
No. Adams County does not require owner occupancy for ADUs. You can build and rent an ADU even if you do not occupy the primary dwelling, but the ADU itself cannot be sold separately from the main home.
How big can my ADU be?
ADUs must be at least 500 sq ft. The maximum is 40% of the primary home's floor area or 750 sq ft (whichever is greater), with a 1,500 sq ft cap on detached ADUs. Height is limited to 25 ft measured to the roof mid-pitch.
Westminster FAQ
Can I build an ADU?
Check Westminster zoning. Colorado’s HB 24-1152 requires certain cities to allow ADUs but local rules vary.
Will my HOA allow it?
Many HOAs restrict or prohibit ADUs. Check your CC&Rs.
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