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September 14, 2021

Proposed Revision of San Diego ADU Code

Full details of NFABSD's ADU code changes proposed to the Mayor and City Council

Over the past several months, Neighbors For A Better San Diego has conducted detailed analysis of the ADU code changes that were approved by the San Diego City Council in October 2020, including responses to numerous questions to Development Services Department staff.

Our analysis has focused on the particular instances where the city has deviated significantly from state law. We also feel that from a policy standpoint, the state's guidelines represent a reasonable compromise between adding housing units to existing single-family neighborhoods and overloading the infrastructure of those neighborhoods. We also feel that by keeping the scope of ADUs within what homeowners can build, ADUs help homeowners provide housing for family members or provide rental income to help pay the mortgage. The number of homeowner ADUs being built was already ramping up before the city's changes went into effect last November, and the revisions that we propose will not hamper that production.

We have also studied a variety of economic data and trends to understand the benefits and shortcomings of San Diego's density bonus incentives. We conclude that the marginal benefit achieved by the allowance of additional units over the state requirements is outweighed by the negative impacts of investor-fueled overbuilding of single-family properties, including crowding out first-time homebuyers, vast increases in vehicle traffic, and overall destabilization of our neighborhoods. We have looked at what other cities have done with regard to affordable housing incentives for ADUs, and our proposed changes include what we think are more effective alternatives to the current density bonus.

Over the past couple of months, we have presented our concerns and discussed possible code changes with Mayor Gloria and all nine Council members and their staffs, culminating with the submission of our specific code revisions to the Council at its September 14 meeting. This submittal included the following documents:

Non-Agenda Public Comments:

Summary of Proposed ADU Code Changes:

Draft Markup of Proposed ADU Code (141.0302 )

Annotated Comparison of State ADU Law and San Diego Code

CA VS SD 2020 ADU Codes

Full text of San Diego's current ADU code (Municipal Code §141.0302):

In addition to providing our recommendations to the City Council, we are also publishing these on our website in order to get public feedback on the proposed changes. If you have any questions or comments, please email them to:

UPDATE 10/4/21: With Governor Newsom's signing of Senate Bill 9 on September 16, NFABSD has updated its proposed San Diego ADU code changes to ensure that no more than 4 units will arise from the splitting of a lot using the rules of SB 9. The Summary of Proposed changes and the Draft Markup have been updated to reflect these changes. For full details, visit:

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