ADU Regulations in Thousand Oaks, California
Ventura County · CA · Pop. 130,000
Max ADU Size
1,200
sq ft detached
Rear Setback
4 ft
Permit Timeline
60 days for ministerial review
Build Cost
$150,000 – $400,000
Zoning
Allowed ADU Types
Thousand Oaks is a planned community with many HOAs — check with your HOA for any architectural review requirements, though HOAs cannot prohibit state-law-compliant ADUs
Source: City of Thousand Oaks — Accessory Dwelling Units · Thousand Oaks Municipal Code Chapter 9-6 (Zoning Ordinance)
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; typically 20–25 ft
side
4 ft
rear
4 ft
Max height: 16 ft (detached); attached follows primary structure height
Lot coverage: Subject to base zone lot coverage; most R-1 lots allow 35–40% coverage
Hillside Grading Ordinance may apply to properties on slopes — verify grading requirements before planning new detached ADU
Permitting
Permit Process
Department
Thousand Oaks Community Development Department
Review Timeline
60 days for ministerial review; typically 30–45 days for conversions
Permit Fees
$4,000 – $16,000
Impact Fees
Waived for ADUs 750 sq ft and under
Required Documents
- ›Building permit application
- ›Site plan showing all structures and property lines
- ›Architectural drawings (floor plans, elevations)
- ›Title 24 energy compliance documentation
- ›Structural calculations (new detached construction)
- ›Grading plan (if site has significant slope)
Thousand Oaks does not currently offer a pre-approved plan program; each submittal reviewed individually
Visit Thousand Oaks Community Development Department →Infrastructure
Utilities & Requirements
Solar
Required
Parking
Not required
Separate Meter
Optional
Fire Sprinklers
See note
Southern California Edison serves Thousand Oaks; panel upgrade is commonly required for new construction ADUs
Financials
ADU Costs in Thousand Oaks
Typical Build Cost
$150,000 – $400,000
Cost per Sq Ft
$250 – $360
Monthly Rental
$1,600 – $3,500/mo
Property Value Added
Adds $170,000 – $320,000 to property value
Available Grants & Programs
- ★CalHFA ADU Grant Program (up to $40,000)
- ★Ventura County home improvement loan programs
Thousand Oaks is one of the more affordable Ventura County markets for ADU construction. Garage conversions are popular given the prevalence of 2-car garages in this suburban community.
Use the free ADU Cost Calculator →Free Service
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Thousand Oaks Quick Facts
- Max size1,200 sq ft
- Rear setback4 ft
- Permit timeline60 days for ministerial review
- Build cost$150,000 – $400,000
- Rental income$1,600 – $3,500/mo
- Owner occupancyNot required
Official Source
City of Thousand Oaks — Accessory Dwelling UnitsThousand Oaks Municipal Code Chapter 9-6 (Zoning Ordinance)
Last verified: March 14, 2026
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