Accessory Dwelling Unit Setback Requirements in Concord

Accessory Dwelling Units (ADUs) in Concord are generally required to maintain an interior side and rear setback of at least four feet. In cases where the principal dwelling encroaches into a setback, the accessory dwelling unit may encroach to the same extent as the principal dwelling to comply with established front and corner-side setback requirements.

Setback Requirements for Accessory Dwelling Units

The City of Concord maintains specific setback standards for Accessory Dwelling Units (ADUs) to ensure compatibility with principal dwellings and neighboring properties. These standards are established under the Development Code:

• Interior Side and Rear Setbacks: Accessory dwelling units in Concord shall provide interior side and rear setbacks of at least four feet [Section 18.200.180(C)(16)(a)].
• Front and Corner-Side Setbacks: Accessory dwelling units in Concord shall comply with the front and corner-side setbacks required for the principal dwelling [Section 18.200.180(C)(16)(b)].
• Encroachment: If the principal dwelling on a Concord property encroaches into a required setback, the accessory dwelling unit may encroach to the same extent as that principal dwelling [Section 18.200.180(C)(16)(b)].

Summary Table of ADU Setback Standards

Setback Type	Minimum Requirement
Interior Side Setback	4 feet
Rear Setback	4 feet
Front Setback	Same as principal dwelling
Corner-Side Setback	Same as principal dwelling

Exceptions and Special Conditions

The City of Concord allows for specific exceptions and variations regarding setback requirements for accessory dwelling units:

• Exempt Accessory Dwelling Units: Certain attached or detached accessory dwelling units measuring up to 800 square feet may be permitted with four-foot side and rear yard setbacks, and these units are not subject to standard lot coverage, floor area ratio, or open space requirements if applying such standards would prohibit the unit's construction [Section 18.200.180(B)].
• Hillside Development: The living areas of accessory dwelling units proposed on any hillside lot are exempt from the hillside development use permit requirements described in Chapter 18.300 [Section 18.200.180(C)(12)].
• Nonconforming Zoning Conditions: The City of Concord will not deny a building permit application for an accessory dwelling unit based on existing nonconforming zoning conditions, building code violations, or unpermitted structures on the property, provided they do not pose a threat to public health and safety [Section 18.200.180(C)(6)].

Sections Cited

• Section 18.200.180(B)
• Section 18.200.180(C)(6)
• Section 18.200.180(C)(12)
• Section 18.200.180(C)(16)(a)
• Section 18.200.180(C)(16)(b)