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If you are looking for an adu contractor in Calabasas, the permit path and the lot itself both shape the project before a single drawing gets made. California consolidated its ADU rules into Government Code sections 66310 through 66342 in 2024, and those rules were updated again on January 1, 2026. Square footage is now measured as interior livable space. Once you submit, the reviewing agency has 15 business days to determine whether the application is complete and 60 days to approve or deny it. Approval is ministerial, meaning no public hearing and no discretionary design review.

For a Calabasas property, that application goes to the City of Calabasas Building and Safety Division, not to Los Angeles County. That distinction matters. Los Angeles County has 88 incorporated cities, and the counter changes from one city to the next even where state rules do not. As a reminder of how local rules can drift from state law, the county’s own ADU ordinance, amended in July 2025 and covering only unincorporated territory, was found non-compliant with state law by the California Department of Housing and Community Development in December 2025. Among other findings, it caps detached ADUs on a multifamily lot at two where state law allows up to eight. A local handout is not always current with the statute.

Calabasas added one more layer worth flagging early. The city adopted an Oak Tree Ordinance under Section 17.32 of its municipal code, and work near a protected oak can require an oak tree permit before construction begins. We identify any protected trees during the initial site walk so that requirement does not surface as a surprise after plans are already drawn.

The housing stock here adds its own set of variables. Most homes are two-story hillside or gated tract builds from roughly the 1970s through the 1990s, a product of the planned hillside subdivisions that were largely built out before the city incorporated on April 5, 1991. Typical layouts include a large but dated kitchen centered on an island and a formal separation from the family room. That floor plan and the grade of the lot together determine where a detached unit can sit, how far utilities need to run, and whether a garage conversion or a new detached build makes more sense for your parcel. We walk the site and check setbacks, grade, equipment access, and utility routes before anything gets drawn.

State law sets a floor that Calabasas cannot go below regardless of local preferences. A local agency cannot cap an ADU below 850 square feet of interior livable space, or 1,000 square feet when the unit has more than one bedroom. Side and rear setbacks cannot exceed four feet. Owner-occupancy cannot be required as a condition of building an ADU. Adding a unit cannot trigger a fire sprinkler retrofit of the main house. And there are no impact fees on a unit of 750 square feet or less. Those protections travel with the parcel wherever it sits within the city.