Accessory Dwelling Units (ADUs) in the RR-40 Rural Residential District
Accessory Dwelling Units (ADUs) are permitted in the RR-40 Rural Residential district of the City of Concord, subject to development and design standards set forth in the Concord Development Code. Owners must obtain a building permit for the construction of an Accessory Dwelling Unit, and the unit must be located on the same lot as a single-family or multifamily principal dwelling.
Permissibility and General Requirements
In the City of Concord, the RR-40 district is classified as a Rural Residential district. Under the Concord Development Code, Accessory Dwelling Units are allowed in all residential districts, including the RR-40 district [Section 18.200.180(C)(7)].
An Accessory Dwelling Unit in the RR-40 district must be subordinate to the principal dwelling. Subdivisions of land that would result in an Accessory Dwelling Unit existing on a separate lot from the principal dwelling are prohibited; however, an Accessory Dwelling Unit may be leased separately from the principal dwelling [Section 18.200.180(C)(4)]. Additionally, short-term rentals (less than 30 days) of an Accessory Dwelling Unit are prohibited [Section 18.200.180(C)(5)].
Size and Design Standards for RR-40 ADUs
Accessory Dwelling Units in the RR-40 district must comply with specific size limitations and design criteria to ensure compatibility with the principal residence.
| Standard | Requirement |
|---|---|
| Minimum Living Area | 150 square feet |
| Maximum Size | Lesser of 50% of the principal dwelling floor area or 1,000 square feet (for lots < 12,000 sq. ft.) / 1,200 square feet (for lots ≥ 12,000 sq. ft.)* |
| Minimum Interior Setback | 4 feet |
| Minimum Rear Setback | 4 feet |
| Maximum Height (Attached) | 25 feet (or lower of principal dwelling height) |
| Maximum Height (Detached) | 16 feet (general); 18 feet (if within 0.5 miles of transit stop/corridor) |
*Note: This size limitation is waived if it restricts the Accessory Dwelling Unit to less than 800 square feet [Section 18.200.180(C)(8)].
Parking Requirements for RR-40 Accessory Dwelling Units
Parking for an Accessory Dwelling Unit is required in addition to the off-street parking required for the principal single-family dwelling.
- Requirement: One off-street parking space is required per Accessory Dwelling Unit or per bedroom, whichever is less [Section 18.200.180(C)(11)(a)].
- Exceptions: Parking is not required if the Accessory Dwelling Unit is within one-half mile walking distance of public transit, is located within a designated historic district, is part of an existing structure conversion, or if there is a car share vehicle site located within one block [Section 18.200.180(C)(11)(b)].
Sections Cited
- Section 18.200.180: Accessory dwelling units
- Section 18.200.180(C)(4): Subdivision
- Section 18.200.180(C)(5): Short-term rentals
- Section 18.200.180(C)(7): Allowed Use
- Section 18.200.180(C)(8): Size
- Section 18.200.180(C)(11): Parking