The Complete Calabasas ADU Requirements Guide
If you’re planning to build an accessory dwelling unit (ADU) in Calabasas, it’s worth getting familiar with the rules before you start. ADUs are secondary housing units—typically a backyard cottage, in-law unit, or converted garage—built on the same lot as a primary home.
Thanks to a series of statewide ADU laws, cities like Calabasas are now required to approve them in most residential areas. In response, Calabasas updated its ordinance in late 2024 to make the process clearer and more consistent.
Keep reading to learn the requirements for building an ADU in Calabasas and how to get it done with Samara.
Calabasas ADU regulations at a glance
Most ADU permits in Calabasas are approved in three to four months. The city is required to review complete submissions within 60 days. ADUs are allowed on any residentially zoned lot with an existing or proposed primary home. While Calabasas has its own zoning and overlay districts, state law sets baseline rules that all cities must follow.
Size and lot requirements
There is no minimum lot size for an ADU in Calabasas. Size and height limits depend on the type:
- Detached ADUs can be up to 1,200 square feet. The base height limit is 16 feet, but up to 18 feet is allowed if the property is within half a mile of a transit stop or has a multifamily building. Up to 20 feet is allowed if the roof pitch matches the primary home. Detached ADUs must also comply with a rear yard coverage limit of 30%.
- Attached ADUs can be up to 1,200 square feet or 50% of the main residence’s floor area, whichever is less. They may be built up to 25 feet tall or to the zoning height limit, whichever is lower. In the Hillside Overlay Zone, the height limit is 25 feet. Attached ADUs may not exceed two stories.
- Junior ADUs (JADUs) must be created entirely within the existing single-family home and are limited to 500 square feet.
All new ADUs must maintain 4-foot side and rear setbacks. Detached units typically need at least 10 feet of separation from the main home. Setbacks do not apply to conversions or rebuilds of existing structures. Additional height may be required in flood zones to meet elevation standards.
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Design requirements
Calabasas applies objective design standards to ensure ADUs are visually consistent with the main residence. These may include matching the roof pitch, exterior materials, or architectural style. In overlay zones like Old Topanga and Calabasas Highlands, additional objective standards may apply, but ADUs must still be approved ministerially if they meet state and local criteria.
Parking requirements
Most new ADUs require one off-street parking space, which can be uncovered and located in a legal driveway, including behind another parked car. However, no parking is required if the ADU is within half a mile of public transit, part of an existing structure, in a historic district, near a car-share location, or on a lot with restricted permit parking. No replacement parking is required when a garage is converted to an ADU. JADUs never require parking.
Zoning eligibility
ADUs are allowed on all residentially zoned lots in Calabasas, including RS (Single-Family Residential), RM (Multi-Family), RR (Rural Residential), HM (Hillside Mountain), RC (Residential Commercial), PD (Planned Development), and OS (Open Space) zones. They are not permitted in RMH (Mobile Home Park) zones. All ADUs must be located on a lot with an existing or proposed primary home. JADUs are allowed only within existing or proposed single-family homes and must be created within the main residence. ADUs are also allowed in overlay areas like Old Topanga and Calabasas Highlands, but must meet additional objective standards.
Meet the KurodasNumber of ADUs allowed
On single-family lots, you can build one detached or attached ADU, plus one JADU within the existing home.
On multifamily lots with an existing residential building, California law allows up to eight detached ADUs—or fewer if that would exceed the number of existing units—and interior conversion ADUs totaling up to 25% of the unit count. If the multifamily building is still under construction, up to two detached ADUs are allowed during development.
Streamline your Calabasas ADU project
If you’re looking to build an ADU, Samara makes it easy. We handle everything from permits to installation and even offer our own financing. Call us at 650-420-2607 to schedule a 15-minute consultation and discover how simple adding a Backyard ADU can be.
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