ADU laws for LA apartment buildings have evolved significantly, creating new opportunities for property owners. This guide explains current regulations and how you can add units to your existing building.
What Is an ADU?
Understanding ADU laws for LA apartments starts with the basics. An Accessory Dwelling Unit (ADU) is a secondary housing unit on a single-family or multifamily property. In Los Angeles, recent state and local laws have made it significantly easier to add ADUs to existing apartment buildings—potentially increasing your unit count and property value.
Why LA Apartment Owners Are Adding ADUs
Adding units to your existing building can:
- Increase rental income without buying a new property
- Boost property value (more units = higher NOI = higher value)
- Take advantage of relaxed regulations that didn’t exist a few years ago
- Address LA’s housing shortage while benefiting financially
Types of ADUs for Multifamily Properties
1. Conversion ADUs
Convert existing non-livable space into a unit:
- Garages and carports
- Storage rooms
- Basements
- Unused common areas
Key benefit: Often the most cost-effective option since the structure already exists.
2. Detached ADUs
Build a new standalone structure on your property:
- Up to 1,200 sq ft allowed
- Must meet setback requirements (4 ft from side/rear)
- 16 ft height limit typically
3. Junior ADUs (JADUs)
Smaller units (up to 500 sq ft) created within existing space:
- Must be within the existing building footprint
- Can share bathroom with main unit
- Requires separate entrance
Current LA ADU Regulations (2025)
What’s Allowed:
- No parking required for ADUs within ½ mile of public transit
- Ministerial approval (no discretionary review) for compliant projects
- No lot size minimum for most ADU types
- Multiple ADUs allowed on multifamily properties
- No owner-occupancy requirement for most ADUs
Multifamily-Specific Rules:
For existing apartment buildings, you can typically add:
- At least 2 detached ADUs
- Conversion ADUs equal to 25% of existing units (minimum of 1)
- Example: A 12-unit building could add 2 detached ADUs + 3 conversion ADUs = 5 new units
The ADU Development Process
- Feasibility assessment: Evaluate your property’s potential
- Design & plans: Work with an architect familiar with LA ADU rules
- Permit application: Submit to LA Department of Building & Safety
- Plan check: City reviews for code compliance (60-day timeline mandated)
- Construction: Build per approved plans
- Final inspection: Get certificate of occupancy
Costs & ROI Considerations
Typical ADU costs in Los Angeles:
- Garage conversion: $100,000 – $200,000
- Detached new construction: $200,000 – $400,000+
- Permits & fees: $10,000 – $30,000
ROI Example:
Adding a 1-bed ADU renting for $2,000/month:
- Annual income: $24,000
- At a 5% cap rate, adds ~$480,000 to property value
- If construction cost is $250,000, you’ve created $230,000 in equity
Impact on Rent Control (RSO)
Important: New ADUs built after 2020 are generally exempt from LA’s Rent Stabilization Ordinance for 15 years, giving you more flexibility on rents.
Common Challenges
- Parking loss: Converting garages means losing parking (but no replacement required near transit)
- Utility connections: May need new meters and service upgrades
- Existing tenant impact: Construction can be disruptive
- Financing: Some lenders don’t count ADU income until stabilized
Quick FAQs
Q: Do I need to live on the property to build an ADU?
A: No. Owner-occupancy requirements have been largely eliminated for ADUs in LA.
Q: Can I short-term rent (Airbnb) my ADU?
A: LA has strict short-term rental rules. ADUs are generally subject to the same restrictions as your primary units.
Q: Will adding an ADU trigger a property tax reassessment?
A: Only the new construction value is reassessed, not your entire property (thanks to Prop 13).
Wondering if ADUs make sense for your building? Request a valuation and we can discuss the potential.
Understanding ADU laws for your LA apartment building can help you maximize property value. Reach out to discuss the ADU potential for your specific property.