Permit Required? Required
Typical Fee Range $1,500–$6,000 Impact fees are waived for ADUs under 750 sq ft of interior livable space per SB 543 (2026).
Fee Method Valuation-based
Apply Online Apply at Los Angeles Department of Building and Safety →

What's Required in Los Angeles

  • Interior livable space definition now excludes wall thickness per 2026 CA state law.
  • Maximum size of 1,200 sq ft for detached ADUs or 50% of the primary dwelling for attached units.
  • Must be located on a lot with an existing or proposed residential unit.
  • No additional parking required if within 0.5 miles of public transit.
  • Solar panels required for newly constructed detached ADUs per Title 24 energy code.
  • Fire sprinklers only required if they are required for the primary residence.

How Much Does an ADU Permit Cost in Los Angeles?

Budget $1,500–$6,000 for the Los Angeles permit itself (valuation-based), issued by the Los Angeles Department of Building and Safety — but treat that as the entry fee, not the total. ADUs are full dwelling units, so the permit stack usually includes building, electrical, plumbing, and mechanical trade permits, plus plan review. One break on record here: impact fees are waived for ADUs under 750 sq ft of interior livable space per SB 543 (2026). Get an itemized fee estimate from the department before finalizing your budget; the spread between a simple conversion and a new detached build is wide.

ADU Size Limits and Zoning Rules in Los Angeles

Before drawing plans, check the two gates that sink most ADU projects: size and zoning. On record here, the size ceiling is 1,200 square feet for detached ADUs or 50% of the primary dwelling for attached units. Other recorded conditions: must be located on a lot with an existing or proposed residential unit; no additional parking required if within 0.5 miles of public transit. Setbacks, height limits, and utility connections layer on top of those rules. The Los Angeles Department of Building and Safety can confirm what your specific lot allows — worth doing before you pay for architectural drawings rather than after.

How to Get a ADU Permit in Los Angeles

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Step 1: Standard Plan Option

Optional: Select an 'LA ADU Standard Plan' to significantly reduce plan check time.

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Step 2: BuildLA Application

Submit the application and plans through the BuildLA portal.

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Step 3: Zoning Review

Planning Dept verifies density, setback, and transit-proximity criteria.

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Step 4: Permit Issuance

Pay building and sewer connection fees (Impact fees waived if <750 sq ft).

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Step 5: Inspection Sequence

Schedule standard inspections (Foundation, Framing, Rough MEP, Final).

Frequently Asked Questions

Yes, the LADBS Standard Plan Program offers dozens of designs that bypass full structural review.
On most single-family lots, you can build one ADU and one Junior ADU (JADU) under 500 sq ft.
Detached ADUs are generally allowed up to 16–18 feet in height depending on transit proximity.
On record, the ceiling is 1,200 square feet — with the exact limit depending on ADU type and lot. Confirm your configuration with the Los Angeles Department of Building and Safety.
Impact fees are waived for ADUs under 750 sq ft of interior livable space per SB 543 (2026).