Calabasas ADUs,
Handled End to End

Most Calabasas lots qualify. California state law (Government Code §65852.2) requires every California city to allow at least one ADU on single-family residential lots, and Calabasas is predominantly zoned single-family with significant Hillside/Mountainous Area overlay across the southern and western foothills, plus the Oak Tree Ordinance applying citywide. What changes per lot is the type and size of ADU that fits, plus how it interacts with protected oaks, slope, and ridgeline. A detached new-build is common on deeper, flatter lots in Calabasas Park and on larger Mountain View Estates parcels. An attached ADU shares a wall with the primary house and is useful when the rear yard is tight or when a protected oak limits a freestanding pad. A garage conversion uses the existing detached-garage footprint and skips many setback rules — particularly useful in Saratoga Hills and Calabasas Highlands. A Junior ADU (JADU) is carved out of the existing primary home, up to 500 sq ft with its own entrance and efficiency kitchen — often the right answer when oaks or slope make a freestanding ADU pad impractical. We confirm zoning, Hillside/Mountainous overlay, oak inventory, and fire-zone classification at the first site visit and recommend the type that fits the property.

Neither. Calabasas is its own incorporated city (incorporated 1991) and issues ADU permits through the City of Calabasas Community Development Department, Building & Safety Division — not LADBS, not LA County. We handle the Calabasas submittal, plan-check corrections, Oak Tree Permit and Hillside/Mountainous Area review where they apply, and final inspection — end to end.

The City of Calabasas Oak Tree Ordinance protects native oak species citywide. Any encroachment within the protected zone of an oak — typically a 15-foot radius from the trunk or the dripline, whichever is greater — and any pruning, root cutting, or removal requires an Oak Tree Permit. For a Calabasas ADU that means the building envelope, foundation, utility trenching, driveway, and grading all need to be drawn around the protected zones of every qualifying oak on the lot. On heavily-oaked parcels in Old Topanga, Saratoga Hills, and parts of Calabasas Highlands the oak inventory often determines where the ADU can sit before zoning setbacks are even considered. A certified arborist report and oak tree protection plan are typically part of the submittal. We map oaks, dripline, and protected zones at the first site visit so the design is buildable and the Oak Tree Permit clears cleanly.

Three site-condition gates apply on top of standard ADU rules. (1) The Calabasas Hillside/Mountainous Area development standards apply to parcels above defined slope thresholds across the southern and western foothills — adding limits on grading and cut/fill volume, building height measured from natural grade, retaining-wall height, ridgeline impact, and driveway slope, and triggering Hillside design review for many projects. (2) Most of Calabasas — particularly Old Topanga, Mountain View Estates, Saratoga Hills, Calabasas Highlands, and Mulholland Heights — falls within a Very High Fire Hazard Severity Zone (VHFHSZ) and is treated as Wildland-Urban Interface (WUI) under Chapter 7A of the California Building Code: ignition-resistant siding and soffits, dual-pane tempered or multi-pane glazing, ember-resistant vents, Class A roof assembly, and defensible-space compliance. LA County Fire serves the area for emergency response and reviews defensible-space and fire-apparatus access on hillside lots. (3) Site work, retaining walls, drainage, and access driveways often dwarf the ADU itself in cost and schedule on hillside parcels — we size that during design rather than discover it in the field.

State law caps required side and rear setbacks at four feet for new detached or attached ADUs and waives setback requirements when you convert an existing garage in its footprint, but oak protected zones, hillside grading limits, and brush-management defensible-space distances often push the ADU envelope farther in. Utilities are real work, not paperwork: water service is by Las Virgenes Municipal Water District; sewer service exists in much of Calabasas, with some hillside parcels still on septic — we confirm at the first site visit. Many Calabasas homes need a panel upgrade before the ADU electrical load can land. Title 24 (California Energy Code) applies in full: new detached ADUs and significant additions trigger solar PV requirements, mandatory high-efficiency envelope and HVAC, electric-ready provisions for cooking and water heating, and EV-charger-ready circuits where the ADU has parking. We design to Title 24 and CALGreen baseline from day one rather than retrofit at plan-check.

Timeline depends on scope, site conditions, and material lead times. Site visit and feasibility, design and drawings, plan-check, and construction are each scoped during consultation, and we provide a realistic schedule in writing once the design is set. Budget varies with ADU type (detached, attached, garage conversion, JADU), lot conditions, finish level, and any hillside, oak, historic, or HOA review that applies — we provide an itemized written quote after the site visit. Rental income varies by neighborhood, finish, and ADU type, and we model realistic numbers with you. Owner-occupancy: AB 670 and AB 671 mean a detached or attached ADU does not require the owner to live on the property, but JADUs continue to require owner-occupancy of one of the two units. Family use is straightforward — adult children, aging parents, in-law suite, work-from-home flex space — and ADUs configured as family units can later convert to rental without rebuild, provided the design anticipated that path. We provide a written cost breakdown at the consultation.