Westlake Village ADU: Regulations, Costs & Permits

• Step 1, City Zoning Clearance: the Planning Director reviews the ADU against the city's standards. It's ministerial, and a denial comes with written comments on how to fix it.
• Building-permit-only path: units that fit state-mandated categories (conversions, or an 800 sq ft detached unit with 4 ft setbacks) can skip the local standards.
• Step 2, LA County building permit: submitted online through LA County's EPIC-LA portal, handled by the county's Calabasas district office. Virtual appointments with plan check engineers are available.
• Standard plans: the city points homeowners to LA County's standard plans and homeowner guide for garage conversions to an ADU or JADU.

ADUs are allowed in the R-1 and RPD zones and in the Mixed Use Lindero and Mixed Use Corsa districts of the North Business Park Specific Plan, on lots with an existing or proposed detached home.

• Detached ADUs: up to 850 sq ft with one bedroom, 1,000 sq ft with two or more.
• Attached ADUs: the same, or 50% of the home's living area, whichever is less.
• Porches count: a covered balcony, porch, or patio counts toward the ADU's square footage.
• Height: detached ADUs are 16 ft, rising to 18 ft near major transit (20 ft to match the roof pitch). Attached ADUs follow the house, up to 25 ft.
• Setbacks: 4 ft side and rear, and the house's front setback unless it would block an 800 sq ft unit. None for conversions or same-footprint rebuilds.
• Separation: 10 ft from other buildings and 8 ft eave to eave, unless that would block the 800 sq ft unit.
• Lot coverage: applies, except where it would block an 800 sq ft, 16 ft ADU with 4 ft setbacks.

The ADU's color, materials, and details, including windows and roof pitch, must match the main house, and the ADU area has to be landscaped consistently with the rest of the lot.

The city's Housing Element notes that every neighborhood but one is governed by CC&Rs, and each of the 20 recognized residential neighborhoods has an active HOA. State law voids CC&Rs that ban or unreasonably restrict ADUs, but HOAs can apply reasonable, objective design rules. Plan for HOA architectural review alongside the city and county.

• Map changes: the city says the state's March 2025 update to LA County's fire hazard maps changed severity areas in Westlake Village, so some neighborhoods are now in moderate, high, or very high zones.
• Code limit in very high zones: the city code allows only one ADU or one JADU on lots in the very high zone, with brush clearance and sprinklers if the house has them. The state has told nearby cities that this kind of cap needs findings and can't block state-guaranteed units, so ask Planning how it's applied today.

Westlake Village's ADU ordinance predates recent state law, and state law controls where they conflict. Under current law, a city can't require owner occupancy for an ADU or a recorded deed restriction on one, JADU owner occupancy is only allowed when the JADU shares a bathroom with the house, and existing multifamily lots can have up to 8 detached ADUs, not the 2 in the city code. If a city handout says otherwise, confirm with Planning.

• Parking: one space for an ADU with at least one bedroom (tandem in the driveway works), with the usual exemptions such as within half a mile of transit. No replacement when you convert or remove a garage. JADUs need no parking.
• Water and sewer: Las Virgenes Municipal Water District, which charges meter and hook-up fees. Lots on septic need local health officer approval.
• Impact fees: none on ADUs with 750 sq ft or less of living space under state law, and proportional fees above that.
• School fees: Las Virgenes Unified, only on ADUs over 500 sq ft.
• Rentals: 30 days or more, and ADUs can't be sold separately.

Who issues ADU permits in Westlake Village?

Both the city and the county. The city Planning Department issues a Zoning Clearance, then LA County Building and Safety issues the building permit through its EPIC-LA portal.

Can my HOA stop me from building an ADU in Westlake Village?

No. State law voids CC&Rs that ban or unreasonably restrict ADUs, but your HOA can apply reasonable, objective design rules.

How big can an ADU be in Westlake Village?

850 sq ft with one bedroom or 1,000 sq ft with two or more, and covered porches and patios count toward that total.

Do I have to live on the property to build an ADU in Westlake Village?

No. The city code still has an owner-occupancy rule, but state law now bars owner-occupancy requirements for ADUs.

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