Basic ADU Requirements
Summary: In Los Angeles, property owners can build ADUs on single-family residential lots without needing a conditional use permit. The state and local laws have been streamlined to encourage ADU development as a solution to the housing crisis.
The California state legislature has passed several bills in recent years that make it easier to build ADUs, including AB 68, AB 881, and SB 13. These laws preempt many local restrictions and establish statewide standards for ADU development.
Size Limitations
Summary: ADU size limits vary by type and lot size, with detached ADUs allowed up to 1,200 square feet on standard lots.
- Detached ADUs: Up to 1,200 square feet for lots 4,000 sq ft or larger. For smaller lots, up to 850 square feet is permitted.
- Attached ADUs: Up to 50% of the primary dwelling or 1,200 sq ft, whichever is less
- Junior ADUs (JADUs): Maximum 500 square feet, must be contained within existing or proposed single-family structure
- Garage Conversions: No size limit if converting existing structure, though must meet other code requirements
These size limits are minimums that cities must allow. Some jurisdictions may permit larger ADUs, but cannot restrict them below these thresholds.
Setback Requirements
Summary: Setback requirements have been significantly reduced, with most ADUs requiring only 4-foot side and rear setbacks.
One of the most significant changes in recent years is the reduction of setback requirements. ADUs can now be built with:
- 4-foot side and rear setbacks (reduced from 5 feet in most zones)
- No setback required for garage conversions or ADUs built in the same location as an existing structure
- Existing structures can be converted without meeting current setback requirements (grandfathered in)
- Front setbacks typically match the primary dwelling requirements
These reduced setbacks make it much easier to fit an ADU on smaller urban lots where space is at a premium.
Height Restrictions
Summary: Height limits range from 16 to 25 feet depending on the number of stories and roof type.
ADUs in Los Angeles are subject to the following height limits:
- 16 feet for detached ADUs (one story with flat roof)
- 18 feet with pitched roof (4:12 slope or steeper)
- 25 feet for two-story ADUs in certain zones
- Must not exceed the height of the primary dwelling in some cases
- Attached ADUs follow the height limits of the primary dwelling
Height is measured from the average finished grade to the highest point of the roof. Architectural features like chimneys and vents may extend beyond these limits.
Parking Requirements
Summary: California law has eliminated parking requirements for most ADUs, making development easier and more affordable.
You do NOT need to provide additional parking if:
- The ADU is within half a mile of public transit
- The ADU is part of the existing primary residence or garage
- There is a car share vehicle located within one block
- The ADU is in a historic district
- Street parking permits are required but not offered to ADU occupants
Even when parking is required, it can be provided as tandem parking, uncovered parking, or through mechanical lifts. Replacement parking is not required when converting a garage to an ADU.
Permit Process
Summary: The permit process typically takes 60-120 days, with cities required to approve or deny applications within 60 days of receiving a complete submission.
Key steps in the ADU permit process:
- Submit plans to LA Department of Building and Safety (LADBS)
- Plan check review (30-60 days) - reviewers check for code compliance
- Address corrections or revisions if needed
- Receive permit approval and pay permit fees
- Schedule inspections during construction (foundation, framing, rough, final)
- Obtain certificate of occupancy after final inspection
The city must approve or deny your application within 60 days of receiving a complete application. If they don't respond within this timeframe, your application is deemed approved.
Owner-Occupancy Requirements
Summary: Owner-occupancy requirements are currently suspended through 2026, allowing more flexibility for property owners.
As of 2025, owner-occupancy requirements for ADUs have been suspended until January 1, 2026. This means you can rent out both your primary residence and ADU without living on the property.
However, this suspension may not be extended, so it's important to:
- Consult with local authorities for the most current regulations
- Plan for potential reinstatement of owner-occupancy requirements
- Consider how this might affect your long-term rental strategy
Utility Connections
Summary: ADUs can have separate or shared utilities, with connection fees waived for units under 750 square feet.
ADUs can have separate utility connections or share utilities with the main house. Key points:
- Junior ADUs must share utilities with the primary dwelling
- Utility companies cannot charge connection fees for ADUs under 750 square feet
- Separate meters allow tenants to pay their own utilities
- Shared utilities are simpler but require landlord to pay or bill tenants separately
Fire Safety Requirements
Summary: All ADUs must meet current fire safety codes including smoke detectors, carbon monoxide detectors, and proper egress.
All ADUs must meet current fire safety codes, including:
- Smoke detectors in all bedrooms and hallways
- Carbon monoxide detectors if gas appliances are present
- Fire sprinklers if the primary dwelling has them (new construction)
- Proper egress windows in bedrooms (minimum 5.7 sq ft opening, 24" high, 20" wide)
- Fire-rated assemblies between attached ADUs and primary dwelling
Conclusion
Los Angeles has made significant strides in making ADU development more accessible. Understanding these zoning laws is crucial for a successful project. At ADU Build Pros, we handle all the zoning research, permits, and approvals so you can focus on enjoying your new ADU.
Ready to start your ADU project? Get a free consultation and estimate today.