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Accessory Structures

How Centennial Handles Accessory Structures: A Practical Guide

By CityRuleLookup Editorial Team

Centennial maintains 86 local ordinances across all categories, and 2 of those deal specifically with accessory structures. Here is a breakdown of what the city actually requires, what is prohibited, and where Centennial falls on the strict-to-permissive spectrum compared to other cities.

Shed & Carport Rules

Centennial lets sheds up to 120 square feet and 10 feet tall sit anywhere in a side or rear yard, but sheds within two feet of the property line need a five-foot opaque screen or a hedge that reaches three feet within 18 months.

Key details: Maximum floor area: 120 square feet. Maximum height: 10 feet to roof peak. Buffer if under 2 ft from line: 5-ft screen or growing hedge. Utility easements: Not allowed without written permission.

Placing a shed within two feet of a lot line without the required screen or hedge, or siting one in a utility easement without written permission, violates § 12-3-603(E)(2) and can trigger a Community Development order to fix or relocate it.

ADU Rules

Centennial allows one accessory dwelling unit per single-family lot, capped at 50% of the principal home's footprint and 17 feet tall if detached, with mandatory registration for non-owner-occupants.

Key details: ADUs per lot: One, single-family lots only. Size cap: 50% of principal home footprint. Detached ADU height: 17 ft. max. Registration: Required if non-owner-occupied; renews annually.

Occupying an unregistered ADU, or failing to renew registration or notify adjacent owners as required, is a Code violation: each day of noncompliance is a separate offense under § 12-3-603(H)(8).

The Bottom Line

Centennial's accessory structures rules are a mixed bag. Some areas are strict, others are relaxed, and the details matter. The best approach is to check the specific rule that applies to your situation rather than assuming Centennial is broadly strict or permissive.

These rules come from Centennial's publicly available municipal code. For complete penalty schedules, exemption details, and answers to common questions, see the individual ordinance pages throughout this guide.