ADU Rules: Centennial vs Littleton
How do adu rules rules compare between Centennial, CO and Littleton, CO?
Centennial and Littleton have similar restriction levels.
Centennial, CO
Arapahoe County
Centennial approved ADU regulations unanimously in 2024. Interior ADUs are limited to 50% of the primary residence. Detached ADUs cannot exceed 800 sq ft. ADUs must match the primary home's design. Under HB 24-1152, owner occupancy cannot be required, and STRs in ADUs are prohibited except in PUDs.
View full Centennial rules →Littleton, CO
Arapahoe County
Littleton passed Ordinance No. 09, Series 2025, allowing ADUs in all residential zones to comply with Colorado HB 24-1152. The ordinance increases maximum ADU size to 1,000 sq ft, eliminates extra parking requirements, and removes design restrictions that don't apply to primary homes. Effective June 2025.
View full Littleton rules →Key Facts Comparison
| Fact | Centennial | Littleton |
|---|---|---|
| Interior Max | 50% of primary residence | - |
| Detached Max | 800 sq ft | - |
| Design | Must match primary home | - |
| STR in ADU | Prohibited (except PUDs) | - |
| Max Size | - | 1,000 sq ft |
| Parking | - | No additional required |
| Owner Occupancy | - | Not required |
| Ordinance | - | No. 09, Series 2025 |
Highlighted rows indicate differences between cities.
Centennial FAQ
Can I build an ADU on my property in Centennial?
Centennial approved ADU regulations unanimously in 2024. Interior ADUs are limited to 50% of the primary residence. Detached ADUs cannot exceed 800 sq ft. ADUs must match the primary home's design. Under HB 24-1152, owner occupancy cannot be required, and STRs in ADUs are prohibited except in PUDs.
What are the size limits for an accessory dwelling unit in Centennial?
Interior Max: 50% of primary residence. Detached Max: 800 sq ft. Design: Must match primary home. STR in ADU: Prohibited (except PUDs).
Littleton FAQ
Can I build an ADU on my property in Littleton?
Littleton passed Ordinance No. 09, Series 2025, allowing ADUs in all residential zones to comply with Colorado HB 24-1152. The ordinance increases maximum ADU size to 1,000 sq ft, eliminates extra parking requirements, and removes design restrictions that don't apply to primary homes. Effective...
What are the size limits for an accessory dwelling unit in Littleton?
Max Size: 1,000 sq ft. Parking: No additional required. Owner Occupancy: Not required. Ordinance: No. 09, Series 2025.
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