Agoura Hills ADU: Regulations, Costs & Permits

• City Planning: zoning review, with a decision or a written list of fixes within 60 days of a complete application.
• City Building & Safety: building permits, applied for on the MGO Connect portal.
• LA County Fire: fire review, including an approval letter at submittal and sign-off before final.
• LA County Environmental Health: septic approval, for lots that aren't on sewer.
• Las Virgenes Unified: school fee receipt before the permit is issued.

• Detached ADUs: up to 850 sq ft of living space for a studio or one-bedroom, 1,000 sq ft with more bedrooms.
• Attached ADUs: the same 850 or 1,000 sq ft, or 50% of the home's living area, whichever is less. They need their own exterior entrance and no interior connection to the house.
• Conversions: a legal accessory structure can become an ADU in its entirety, with any expansion capped at 1,000 sq ft total.
• Height: detached ADUs are 16 ft to the peak, or 18 ft where state law allows. Attached ADUs follow the house's limit, up to 25 ft.
• Setbacks: 4 ft side and rear, the house's front setback, and 10 ft between a detached ADU and the house. None for conversions or same-footprint rebuilds.
• The 800 sq ft guarantee: one ADU up to 800 sq ft, 16 ft tall, with 4 ft setbacks is always allowed, regardless of lot coverage, front setback, or horse-keeping area rules.

• Matching: exterior materials, colors, and finishes match the main home.
• Lighting: fully shielded and aimed down.
• Old Agoura: in the Old Agoura Design Overlay District, a detached ADU can sit in the required front yard if it covers no more than 25% of it.
• State-exempt units: ADUs that qualify under state law get only building, fire, and health review, without these local standards.

• Most of the city is high or very high: the city's own ADU FAQ says most properties are in a High or Very High Fire Hazard Severity Zone, and fuel modification may be required.
• Separation: in a very high zone, detached ADUs stay 10 ft from other structures, unless that would block an 800 sq ft unit. Then a smaller gap is allowed with fire-resistant construction.
• Access roads: LA County Fire may require a fire access road or driveway if any part of the ADU is more than 150 ft from the street.
• Sprinklers: required in the ADU if the main house requires them.

• Protected trees: all scrub oaks of any size, and any oak, California sycamore, or Southern California black walnut 6 inches or more in diameter, are protected. Removing one or working inside its protection zone needs a protected tree permit. On wooded Agoura lots this often decides where the ADU can go.
• Hillside lots: parcels with an average slope over 10% fall under the city's hillside grading and design rules. Grading over 50 cubic yards generally needs a grading plan and permit.
• Equestrian Overlay: the city can make the horse-keeping area optional on lots under 10,890 sq ft or with slopes over 25%.
• Septic: if the house is on sewer, the ADU connects too, with a Las Virgenes Municipal Water District connection permit and fee. If not, a new or upgraded septic system may be needed, approved by LA County Environmental Health before the city signs off.

Agoura Hills offers free plans by RRM Design Group in three sizes (a 550 sq ft studio, a 750 sq ft one-bedroom, and a 1,000 sq ft two-bedroom) and three styles (Cottage, Ranch, and Spanish), with slab or raised foundations. They're all-electric, so no gas line. Pre-approved plans skip building plan review fees, and the city estimates about 5 business days for the first review and 5 for a second. You still provide a site plan, plus grading or septic plans if your lot needs them.

• Impact fees: none on ADUs with 750 sq ft or less of living space. Larger units pay in proportion to the house.
• School fees: paid to Las Virgenes Unified, which can only charge on ADUs over 500 sq ft.
• Building fees: based on the construction valuation.
• Solar: required on newly built detached ADUs, with a separate permit.
• Parking: one space (tandem on the driveway is fine), unless a state exemption applies. None for JADUs, and no replacement when you convert a garage.
• Rentals: 30 days or more. Short-term rentals are prohibited, and ADUs can't be sold separately.
• Owner occupancy: not required for ADUs. The city code requires JADU owners to live on site with a recorded deed restriction, though state law now limits owner occupancy to JADUs that share a bathroom with the house.

Does Agoura Hills have free ADU plans?

Yes. The city offers free pre-approved plans for a 550 sq ft studio, a 750 sq ft one-bedroom, and a 1,000 sq ft two-bedroom, in Cottage, Ranch, or Spanish styles, with about 5 business days per review.

How big can an ADU be in Agoura Hills?

Up to 850 sq ft for a studio or one-bedroom and 1,000 sq ft with more bedrooms. An 800 sq ft ADU is always allowed, whatever the lot coverage.

Can I build an ADU in a very high fire zone in Agoura Hills?

Yes. The 2025 ordinance removed the old one-unit limit on very high fire lots. Expect fuel modification, 10 ft separation where feasible, and LA County Fire review, including a possible access road if the ADU is over 150 ft from the street.

Will oak trees affect my Agoura Hills ADU?

Often. All scrub oaks and any oak, sycamore, or black walnut 6 inches or more across are protected, and building inside a tree's protection zone requires a protected tree permit.

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