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All ADU Regulations

Berkeley, California

Berkeley has updated its ADU ordinance to comply with new state laws. Read the up-to-date requirements & what to watch out for when building an ADU in Berkeley.
Updated Sep 04, 2020


All properties zoned for residential use may be eligible to build ADUs, with the exclusion of:
  • Environmental Safety- Residential (ES-R)
  • Manufacturing (M)
  • Mixed Manufacturing (MM)
  • Mixed Use-Light Industrial (MU-LI)
  • Unclassified (U)
  • on a lot with frontage on a roadway with less than 26 feet in pavement width in the Hillside Overlay (H)

Types of ADUs

Berkeley defines different types of ADUs:
  • Jr. ADU (JADU): interior conversion of existing livable space (e.g. bedroom or finished basement)
  • Conversion ADU: interior conversion of existing non-habitable area (e.g. garages, carports, unfinished basements)
  • Attached ADU: new construction attached to existing structure
  • Detached ADU: new construction detached from existing structures

Number of units

The number of ADUs you’re able to build depends on how your lot is zoned:
  • Lots zoned for single family use may add 1 ADU and1 Jr. ADU (JADU).
  • Lots zoned for multi-family may add 2 new detached ADUs and at least one conversion ADU (interior conversion of existing building, but no more than 25% of the original number of units. (E.g. an apartment with 4 units may add 2 detached ADUs and 1 conversion ADU.)

Building size

The maximum ADU you can build depends on your zoning and ADU type:
  • JADUs may reach a maximum of 500 sq. ft.
  • Conversion ADUs can reach 850 sq. ft. for a studio / 1 bedroom, and 1,000 for a 2+ bedroom
  • Attached ADUs can reach no more than 50% of the floor area of the existing dwelling
  • Detached ADUs can reach 1,200 sq. ft.

Building height

Detached ADUs can reach a maximum height of 16 feet. Attached ADUs must comply with the height requirements of the applicable zoning district.


Existing unfinished basement space can be used for a conversion ADU.


Minimum setbacks of 4 feet from the side and rear lot lines, as well as 6 feet from any existing structures are required for detached ADUs.


No additional parking is required for ADUs. Even when converting a garage or carport, replacement parking is not required.


Owner occupancy is not a requirement for permitting an ADU from January 1, 2020 until January 1, 2025. This is a great opportunity for rental property owners to increase their yields in a cost-effective way.


While long-term rentals are permitted for ADUs, short-term rentals (e.g. Airbnb for less than 30 days) are not permitted in Berkeley.


Impact fees are waived for ADUs less than 750 sq. ft. Utility and connection fees are waived for JADUs and conversion ADUs in single family properties.


Do you have a utility easement over your property? Do you have special setbacks? Reach out to us and we’ll help you build a custom ADU to fit your unique property characteristics and local regulations!

Want to learn more about ADU regulations in your area?

Book a free consultation and estimate with a Cottage ADU Expert to find out what’s possible on your property!