Mar 1, 2021 0 Comments in Uncategorized by

HAC recently welcomed architect Mark Hogan (OpenScope Studio) and attorney Brett Gladstone (Goldstein, Gellman, Melbostad, Harris & McSparran) to discuss updates to California ADU laws. 


But what, you may be wondering, are ADUs? Let’s take a quick(ish) look. 


Commonly called  “Granny Flats” or  Secondary Units, an Accessory Dwelling Unit (ADU) is a secondary residential unit constructed on the same property as the primary structure and consists of independent living facilities. ADUs have been widely publicized for  serving as affordable sanctuaries in communities  with soaring housing prices and also providing physical separation among family members while still ensuring proximity. In addition to offering more affordable rents,  ADUs   also require lower construction costs because   they don’t  require the infrastructure or impact fees of a single-family home. For these and other reasons ADUs have become an increasingly popular solution to California’s housing shortage and affordability crisis among  housing advocates, developers, and legislators.  


Today’s ADUs fall under four categories: Conversion, Junior, Attached, and Detached ADUs. 

  • Conversion ADUs are constructed by converting space of the primary residence, such as a basement, or the entire accessory building, such as a shed, into an independent living space. 
  • Junior ADU (JADU) is a specific Conversion ADU constructed entirely within an existing or proposed single-family home, distinguished by its reduced construction costs and shared facilities.
  • Attached ADUs add onto the single-family residence. 
  • Detached ADUs are independent structures, unattached to the primary building. 

In planning an ADU’s construction, one needs to consider the property’s zoning code, parking requirements, bicycle parking, set backs and open space, access to natural light, height limits, and residential designs.  


In response to rising housing costs, state and local municipalities have sought to increase ADU production by reducing bureaucratic regulations and waiving areas of the Planning Code. For example, California passed SB 1069 and SB 2299 in 2016 to limit cities’ authority in regulating ADUs by ensuring their accordance with the state program. In 2017, the passage of SB 229 and AB 494 authorized ADUs through a ministerial, rather than a discretionary, process and waived parking requirements for ADUs within a half-mile radius of transit stops. 


In 2020, AB 68 and AB 881 were enacted to further streamline and expedite the ADU permitting process by allowing a 60-day review timeframe and waiving requirements for design review, CEQA, Planning Code Section 311, and discretionary reviews. The bills also enable greater residential infill by granting the addition of ADUs and JADUs to existing single-family and multi-family dwellings and prohibiting local agencies from establishing the maximum size of an ADU of less than 850 square feet or 1000 square feet if it contains more than one bedroom. 


In response to these more flexible regulations, cities have seen a substantial increase in ADU permit applications. 


Which brings us to 2021 and HACs conversation with Mark and Brett about the most recent ADU updates.


Mark discussed changes at the state level which now: 

  • Authorize two ADUs per parcel on single family lots
  • Remove size limits on ADU 
  • Grant automatic approval to Conversation ADUs 
  • Eliminate parking restrictions within a half mile of a bus stop 

Brett discussed changes at the local level in San Francisco which now:

  • Proposed two options for the approval process: A streamlined ADU approval process that’s more in line with state law, and a ministerial process that is entirely administrative.
  • Allows for one ADU through the streamlined approval process and two ADUs through the ministerial process. 

The speakers’ presentation also highlighted the ambiguity of the City’s ADU guidelines, distinct from the concrete requirements of the state regulations, and permits a “picking and choosing” of ADU requirements. It also seems to inevitably push people towards additional steps, such as acquiring a Costa Hawkins waiver and a NSR. The need for greater consistency and HCD’s enforcement of state provisions would foster a more smooth process in permitting and constructing ADUs for our housing supply. 


About the Author

Housing Action Coalition

The Housing Action Coalition is a member-supported nonprofit that advocates for building more housing at all levels of affordability to help alleviate the Bay Area's housing shortage, displacement, and affordability crises.

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