ADU Regulations in Antioch, California
Contra Costa County · CA · Pop. 115,000
Max ADU Size
1,200
sq ft detached
Rear Setback
4 ft
Permit Timeline
60 days
Build Cost
$150,000 – $305,000
Zoning
Allowed ADU Types
ADUs and JADUs permitted by right on all residentially zoned lots. Antioch is an East Bay inland city that has expanded transit access through the eBART extension, increasing its appeal as an affordable Bay Area alternative. State law preempts owner-occupancy requirements.
Source: City of Antioch — Accessory Dwelling Units · Antioch Municipal Code Title 9 (Zoning), Chapter 9-5.35
Dimensions
Size & Setback Requirements
Detached
1,200
sq ft max
JADU
500
sq ft max
Attached
50% of primary home, max 1,200 sq ft
Setbacks
front
Same as primary dwelling per underlying zone
side
4 ft
rear
4 ft
Max height: 16 ft
Lot coverage: Per underlying zone
Antioch's mix of older and newer residential neighborhoods provides a range of ADU opportunities. Newer east Antioch subdivisions have larger lots while older west Antioch neighborhoods feature smaller lots more suited for garage conversions or attached ADUs.
Permitting
Permit Process
Department
City of Antioch — Planning and Community Development Department
Review Timeline
60 days
Permit Fees
$7,000 – $13,000
Impact Fees
Impact fees waived for ADUs under 750 sq ft; prorated for larger units
Required Documents
- ›Site plan with property dimensions and setbacks
- ›Floor plans
- ›Elevations
- ›Title 24 energy compliance report
- ›Structural drawings
- ›Grading and drainage plan (if applicable)
Antioch processes ADU permits within state-mandated timelines. The eBART extension to Antioch (Pittsburg/Bay Point and beyond) has made the city more transit-accessible, driving interest from Bay Area workers seeking affordable housing options. Permit fees reflect Contra Costa County staffing costs.
Visit City of Antioch — Planning and Community Development Department →Infrastructure
Utilities & Requirements
Solar
Required
Parking
Not required
Separate Meter
Optional
Fire Sprinklers
See note
Financials
ADU Costs in Antioch
Typical Build Cost
$150,000 – $305,000
Cost per Sq Ft
$210 – $275
Monthly Rental
$1,500 – $2,300/mo/mo
Property Value Added
Adds $115,000 – $210,000 to property value
Available Grants & Programs
- ★CalHFA ADU Grant Program available (up to $40,000)
- ★Contra Costa County housing programs may be available
The eBART extension has made Antioch a more viable Bay Area bedroom community, boosting ADU rental demand. As one of the more affordable East Bay cities, Antioch attracts renters priced out of Oakland, Walnut Creek, and Concord. ADU returns are favorable relative to construction costs.
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Antioch Quick Facts
- Max size1,200 sq ft
- Rear setback4 ft
- Permit timeline60 days
- Build cost$150,000 – $305,000
- Rental income$1,500 – $2,300/mo/mo
- Owner occupancyNot required
Official Source
City of Antioch — Accessory Dwelling UnitsAntioch Municipal Code Title 9 (Zoning), Chapter 9-5.35
Last verified: March 14, 2026
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