Accessory Dwelling Unit Zoning Regulations in Concord

Accessory dwelling units (ADUs) and junior accessory dwelling units (JADUs) are permitted in several zoning districts within the City of Concord, provided they meet specific development and design standards. These units are allowed in districts that permit single-family or multifamily principal dwelling residential uses to increase the availability of smaller and affordable housing options.

Permitted Zoning Districts for Accessory Dwelling Units

Accessory dwelling units are permitted in the following zoning districts within the City of Concord that allow for single-family or multifamily principal dwelling residential uses [Section 18.200.180(C)(7)]:

Zoning District
R (Residential)
NTS (North Todos Santos)
CO (Community Office)
CMX (Commercial Mixed-Use)
NC (Neighborhood Commercial)
DP (Downtown Pedestrian)
DMX (Downtown Mixed-Use)

General Development Standards for Accessory Dwelling Units

Accessory dwelling units must comply with the requirements of the zoning district in which they are located, in addition to specific standards set forth in the Concord Development Code [Section 18.200.180(C)(9)].

Size Limitations

The living area of an accessory dwelling unit must be at least 150 square feet and may not exceed 50 percent of the floor area of the principal dwelling, subject to the following maximums [Section 18.200.180(C)(8)]:

Lot Net Area	Maximum ADU Size
Less than 12,000 square feet	1,000 square feet
12,000 square feet or greater	1,200 square feet

Note: This limitation will be waived if it restricts the accessory dwelling unit to less than 800 square feet [Section 18.200.180(C)(8)].

Height and Setback Requirements

Accessory dwelling units must maintain an interior side and rear setback of at least four feet [Section 18.200.180(C)(16)]. Height requirements for accessory dwelling units are as follows [Section 18.200.180(C)(17)]:

Attached Accessory Dwelling Units: Height shall not exceed 25 feet or the height limit of the principal dwelling, whichever is lower.
Detached Accessory Dwelling Units: Generally limited to 16 feet in height, though this may be increased to 18 feet under specific conditions related to transit proximity or if located on a lot with an existing multifamily principal dwelling.

Prohibitions and Requirements

Subdivision: No subdivision of land or air rights is permitted that would result in the accessory dwelling unit existing on a separate lot from the principal dwelling [Section 18.200.180(C)(4)].
Rentals: Accessory dwelling units or junior accessory dwelling units shall not be rented for a term of less than 30 days [Section 18.200.180(C)(5)].
Parking: Required parking for an accessory dwelling unit is in addition to the parking required for the principal dwelling, unless a specific exemption applies (such as location within one-half mile of public transit) [Section 18.200.180(C)(11)].

Sections Cited