Potential of ADUs

Streamlining Policy, Planning, and Codes for ADUs


At the start of 2020, new legislative changes governing ADUs and secondary building units have gone into effect in California to promote more housing on existing single and multi-family residential lots. The most recent set of laws has removed many of the zoning obstacles like requiring off-street parking in most cases, and minimum lot sizes, however, this has led to emerging tensions between confused homeowners, contractors, and understaffed and underprepared permitting offices. The rules at the state level still need to be adopted and customized by jurisdiction, and cities and counties are in very different stages of adopting new policies with very different practices and resources for homeowners and builders.

In addition, ADU’s are required to pass the current residential building codes, however, some of these codes—especially California’s ambitious energy and green building codes—may need to be right sized for these smaller homes to be more accessible and comfortable to live in. In this session we explore how we might address some of these challenges and explore some best practices and approaches by welcoming three different perspectives on policies, planning and code for ADUs.

Learn more about this series here

Hosted by:

Darin Ranelletti

As Policy Director for Housing Security, Darin works to promote safe, healthy, affordable, and stable housing in the City of Oakland and recognizes ADUs as part of the solution. 

Guest Speakers:

Peggy Jensen

Peggy is the Deputy County Manager for the County of San Mateo. She leads their task force for the Second Unit Center, a program to empower homeowners to build second units and help increase the affordable housing supply in the County.

“Over 70% of San Mateo County are single family. We have land available, we have equity available. And the thought was ADUs could very well be a solution for affordable housing.”

– Peggy Jensen

Sarah Shull

As the City of San Jose’s ADU Ally, Sarah helps guide homeowners and building professionals through the process of building an ADU and accessing the City’s pre-approved ADU designs, financing options and educational workshops.

“Education and helping homeowners understand where their money is going is really important. Homeowners want to know: how do I pay for it? How long is it going to take? How many professional teams do I need in my corner? And do I want to do this with all of this information?”

– Sarah Shull

Wes Sullen

Wes is Director of the LEED program team at the US Green Building Council. He leads the organization’s technical alignment with LEED and green building codes, and directs Materials and Resources activities for the USGBC. 

“With climate change, codes have had to pick up new strategies and techniques, but that often means more complexity. California building code, which is one of the best in the world, has about 6,000 pages in it currently, but that is a lot to get through when you’re trying to build something fast.”

– Wes Sullen

Action steps you can take

  1. Learn more about Life Cycle Analyses (LCAs). and answers to commonly asked questions by reading the Department of Housing and Community Development (HCD)’s ADU Handbook.
  2. Explore pre-approved ADU designs and pre-certified factory-built (pre-fab) homes for faster permitting and reduced upfront costs. Individual cities and counties are always updating what’s been pre-approved.
  3. New to homebuilding? Learn more about California’s building code, specifically Title 24 energy code and CalGREEN. This will help clarify what to include in your ADU to make it code-compliant and healthier for occupants and the environment.
  4. Thinking of doing a garage conversion? The Casita Coalition and its members across the state have created a resource called Guidelines for Garage Conversion ADUs to help better understand the different requirements of attached and detached garage conversions, the implications of unpermitted structures, and answers to commonly asked questions. 
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Alex Coba

Communications Associate

As a proud California native from Stockton, Alex brings a wealth of experience and a versatile skill set. He has a solid communication background with a Bachelor of Arts in Journalism and Public Relations from California State University, Chico. Alex is adept at strategic communications and media relations, with experience gathering and sharing stories from his local communities that uplift the unique spirit and values of those places. He is excited to join Build It Green, where he can apply his talents to further BIG’s mission to help communities across California thrive.