ADU Rules In Calabasas: What Homeowners Should Know

Thinking about adding an accessory dwelling unit to your Calabasas property? Whether you want a guest cottage for multigenerational living, a home office with privacy, or future rental income, an ADU can be a smart way to elevate both lifestyle and long‑term value. The key is understanding how California’s rules intersect with Calabasas’ local standards so you can design it right the first time.

In this guide, you’ll learn what state law requires, what Calabasas typically checks, how permits flow, and where hillside, fire, and HOA rules come into play. You’ll also get a simple checklist to move from idea to approved plans. Let’s dive in.

What counts as an ADU

An accessory dwelling unit is a secondary, self‑contained residential unit on the same lot as a primary home. It can be detached, attached, or created by converting existing space like a garage or bonus room. A junior ADU is a smaller unit created within the existing home.

State law recognizes ADUs and JADUs and limits how cities can restrict them. For an overview of definitions and statewide guidance, review the California Department of Housing and Community Development’s ADU resources, which explain unit types, approvals, parking, and fees. You can find that overview on the HCD ADU page.

State rules that shape local approvals

California Government Code § 65852.2 sets the statewide framework for ADUs. It requires streamlined, ministerial approval when your plans meet objective standards. It also limits parking requirements and allows a range of ADU types, including garage and interior conversions. You can read the statute text in California Government Code § 65852.2.

Key state highlights to know before you design:

• JADUs have a maximum size of 500 square feet and must be created within the existing single‑family home.
• Detached and attached ADUs are allowed statewide, subject to objective standards and local development rules that fit within state constraints.
• Parking is limited by exemptions that may apply if you convert existing space or are near transit. Details flow from the statute and are summarized by HCD.
• Cities must process qualifying ADUs ministerially, which avoids discretionary hearings when you meet objective standards.

For plain‑English guidance, the HCD ADU resources page provides a helpful overview.

Calabasas standards to confirm first

Calabasas implements state law through its municipal code and objective design standards. Before you hire an architect, verify the following with the City of Calabasas Planning Division:

• Zoning and overlays. Confirm your base zone and whether your lot sits in a scenic corridor, hillside overlay, open space, or other area with additional standards. Start with the City of Calabasas Planning Division page.
• Maximum unit size and FAR. Ask whether Calabasas uses an absolute cap, a percentage of your primary home, or lot‑based formulas. If converting a garage or interior space, confirm how that counts toward floor area rules.
• Setbacks and height. Many cities use modest side and rear setbacks for detached ADUs and apply standard front setbacks to new structures. Verify Calabasas’ exact setback and height limits, and how height is measured on sloped lots.
• Lot coverage and minimum lot size. Check whether coverage limits or lot size thresholds affect a detached ADU.
• Parking. Confirm if a space is required for your design and whether any state exemptions apply, such as proximity to transit or conversion of existing space.
• Utilities and sewer. Determine if you are on city sewer or septic, and whether separate meters or capacity upgrades are needed. For sewer and water service in much of Calabasas, review the Las Virgenes Municipal Water District resources.
• Fees. Ask Planning and Building about plan check, permit, and any impact or utility connection fees, including potential reductions for smaller units.
• Design standards. Learn which objective design rules apply to materials, windows, privacy, and roof forms, especially if the ADU is visible from public areas.

Parking and utilities basics

State law limits parking requirements for ADUs, and exemptions may apply when:

• You convert existing space, such as a garage or basement.
• The property is within one‑half mile of public transit.
• There are specific conditions outlined by state statute.

Because the details matter, confirm how Calabasas applies these exemptions to your address. For utilities, clarify whether your design needs separate water or electrical meters, and coordinate early on sewer capacity or septic design. Contact your utility providers to understand connection standards and timelines.

Permit path and timeline in Calabasas

Most compliant ADUs are reviewed ministerially, which means no public hearing and a more predictable process. Here is the typical path:

1. Pre‑application checks. Confirm zoning, overlays, setbacks, height, lot coverage, parking, and whether any design review triggers apply. A brief consultation with Planning can surface issues early.
2. Prepare your submittal. Provide a site plan, floor plans, elevations, construction and structural details, and utility plans. Conversions often require documentation of existing conditions.
3. Planning review. If your plans meet objective standards, expect ministerial approval. Discretionary items, such as variances or certain overlay triggers, can lengthen the process.
4. Building plan check. Structural, electrical, plumbing, mechanical, and energy compliance are reviewed by the Building Division.
5. Fire review and inspections. In high fire‑risk areas, additional access, defensible space, or sprinklers may apply.
6. Permit issuance and construction. After approvals and fees, permits are issued. Construction proceeds with staged inspections and a final sign‑off for occupancy.

Timelines vary by complexity and application completeness. Straightforward interior or garage conversions can move from submittal to permits in a few weeks to a few months. Detached ADUs, grading, or hillside work can take longer due to engineering, fire, and site constraints.

Hillside, fire, and environmental factors

Many Calabasas neighborhoods are in hillside and high fire‑severity areas. Plan for:

• Geotechnical studies for slopes, retaining walls, and soil stability if your lot is not level.
• Wildfire‑resilient design, including defensible space, ember‑resistant vents, and Class A roofing where required by the fire authority.
• Tree protection, creek setbacks, or biological resource review on sensitive sites.

Small, code‑compliant ADUs are often exempt from broader environmental review, but site conditions can add steps. Early conversations with Planning and your design team help you avoid redesigns later.

HOAs, CC&Rs, and design review

If your property is in an HOA, review your CC&Rs as early as possible. State law limits HOA bans on ADUs, but associations can apply reasonable aesthetic controls. Align your exterior materials, roof form, and window placement with both objective city standards and your HOA’s architectural rules.

On visible or scenic sites, expect objective design criteria to protect neighborhood character and privacy. Your architect can balance those standards with a floor plan that feels livable and private for both the main home and the ADU.

Quick feasibility checklist

Use this to scope your project in a single afternoon:

1. Confirm your zoning and overlays with the City of Calabasas Planning Division.
2. Identify whether your property is on sewer or septic and which utilities serve your address. Review Las Virgenes Municipal Water District if applicable.
3. Measure available side and rear yard areas to test detached ADU footprints against likely setbacks.
4. Assess conversion options first. Interior and garage conversions are often the fastest and most cost‑effective.
5. Note hillside, fire severity, or access constraints that could trigger extra reviews or costs.
6. Review HOA CC&Rs and start an HOA conversation if needed.
7. Get preliminary estimates from an architect and contractor, including permit and connection fees.
8. Ask Planning whether your plan is fully ministerial or if any discretionary items could extend your path.

When to bring in pros

Consider engaging these professionals early if your lot is constrained or in an overlay:

• Architect or residential designer to optimize size, privacy, and compliance.
• Contractor or ADU builder for realistic budgets and construction sequencing.
• Civil or geotechnical engineer for grading, drainage, or retaining structures on slopes.
• Planning consultant or land‑use attorney for HOA conflicts or variances.
• Permitting specialist to coordinate multi‑department submittals.

Bottom line for Calabasas homeowners

California has made ADUs more feasible, but your success still depends on aligning design, parking, utilities, and hillside or fire requirements with Calabasas’ objective standards. Start with a quick feasibility check, confirm the details with Planning, and bring in the right design and build partners early.

If you want to understand how an ADU could influence your home’s marketability, rental potential, or future resale strategy, connect with the local team that serves Calabasas, Westlake Village, and Lake Sherwood. Reach out to the Michelle Price Realty Group to Request a Confidential Consultation.

Helpful resources

• Review the statute in California Government Code § 65852.2 for statewide ADU rules.
• Explore the California HCD ADU resources for clear statewide guidance.
• Start with the City of Calabasas Planning Division to confirm local standards and submittal steps.
• For water and sewer service in much of Calabasas, check Las Virgenes Municipal Water District for connection requirements.

FAQs

What size ADU can you build in Calabasas?

• State law allows a range of ADU types and sizes within objective local standards; JADUs are capped at 500 square feet, and you should confirm Calabasas’ current maximums with the Planning Division.

Do you need parking for an ADU in Calabasas?

• Parking can be required, but state exemptions apply in several cases, such as conversions of existing space or proximity to transit, so verify how those apply to your address with Planning.

How long do ADU permits take in Calabasas?

• Ministerial approvals for complete applications can move in weeks to a few months, while detached units on slopes or with grading can extend timelines due to engineering and reviews.

Can you rent out an ADU in Calabasas?

• State law allows ADU rentals, but local rules may limit short‑term rentals; check Calabasas’ current regulations for minimum rental durations and occupancy.

What is the difference between an ADU and a JADU?

• An ADU is a self‑contained unit that can be detached or attached, while a JADU must be within the existing home and is capped at 500 square feet by state law.