ADU Regulations in Concord, California
Contra Costa County · CA · Pop. 130,000
Max ADU Size
1,200
sq ft detached
Rear Setback
4 ft
Permit Timeline
60 days
Build Cost
$170,000 – $340,000
Zoning
Allowed ADU Types
ADUs are permitted by right on all residential lots. Concord uses functional zone names (SFR = Single-Family Residential, LDR/MDR/HDR = Low/Medium/High Density Residential). The former Naval Weapons Station redevelopment area is planned for mixed-use development; ADU rules in that area will follow standard residential regulations once built out.
Source: City of Concord — Accessory Dwelling Units · Concord Municipal Code Title 18 (Zoning), Chapter 18.165
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
side
4 ft
rear
4 ft
Max height: 16 ft (detached); up to 25 ft if attached or above garage
Lot coverage: Per underlying zone; SFR typically 40–45%
Concord's post-war tract neighborhoods offer consistently sized lots (typically 6,000–8,000 sq ft) that comfortably accommodate detached ADUs while meeting setback requirements. Neighborhoods near the Pleasant Hill/Contra Costa Centre BART station — which straddles the Concord/Pleasant Hill border — are particularly desirable for transit-oriented ADUs.
Permitting
Permit Process
Department
Community and Economic Development Department
Review Timeline
60 days
Permit Fees
$8,000 – $16,000
Impact Fees
Impact fees waived for ADUs under 750 sq ft; Mt. Diablo Unified or other school district fees assessed separately
Required Documents
- ›Site plan with dimensions, setbacks, and existing improvements
- ›Floor plans
- ›Elevations
- ›Title 24 energy compliance
- ›Structural drawings
- ›Utility connection diagram
Concord maintains a dedicated ADU webpage with submittal requirements and fee schedules. The city participates in Contra Costa County's countywide ADU resource program. Plan check is handled jointly by Planning and Building; inspections are managed by the Building Division. Concord Fire Department reviews fire/life-safety.
Visit Community and Economic Development Department →Infrastructure
Utilities & Requirements
Solar
Required
Parking
Not required
Separate Meter
Optional
Fire Sprinklers
See note
Financials
ADU Costs in Concord
Typical Build Cost
$170,000 – $340,000
Cost per Sq Ft
$235 – $305
Monthly Rental
$1,800 – $2,800/mo/mo
Property Value Added
Adds $170,000 – $310,000 to property value
Available Grants & Programs
- ★CalHFA ADU Grant Program available (up to $40,000 for pre-development costs)
- ★Contra Costa County HOME Investment Partnership funds
- ★Bay Area HEART (Housing Endowment and Regional Trust) programs
Concord's BART connectivity is its strongest ADU value driver. Units within a half-mile of the Concord or Pleasant Hill/Contra Costa Centre BART stations consistently command rents at the upper end of the range and experience minimal vacancy. Bay Area housing costs continue to push renters outward, sustaining strong demand in Contra Costa County.
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Concord Quick Facts
- Max size1,200 sq ft
- Rear setback4 ft
- Permit timeline60 days
- Build cost$170,000 – $340,000
- Rental income$1,800 – $2,800/mo/mo
- Owner occupancyNot required
Official Source
City of Concord — Accessory Dwelling UnitsConcord Municipal Code Title 18 (Zoning), Chapter 18.165
Last verified: March 14, 2026
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