Methodology

For this report, we reviewed the 201 ordinances received by California’s Department of Housing and Community Development (HCD) by September 6, 2019. We evaluated the ordinances that had been submitted to HCD, and when information was missing from an ordinance (e.g., for data on fees), we searched the jurisdiction’s website. With some 540 municipalities and counties expected to submit ordinances, this represents 37.2 percent of the state. In some cases, jurisdictions have modified their ordinances but failed to notify the state; we have evaluated an additional three ordinances in this category, for a total of 204. But when jurisdictions fail to submit an ordinance, State law governs their ADU regulations. When jurisdictions default to state standards, but did not submit an ordinance, we do not provide a grade.1

In order to “grade” the ordinances, we created a rubric to score the ADU regulations of each city or county. There are 16 equally weighted criteria (see the “Grades” tab of this webpage for grading criteria and rubric). Some of these come from the legislation passed in 2016 or 2017, while others come from the 2019 reforms. Three of these offer opportunities to gain extra credit, which include Parking Requirements for ADUs, and Maximum Size for Attached and Detached ADUs.2 Each criterion is valued between 5-20 points, with the exception of Additional Layers of Entitlement or Review, for which jurisdictions may only receive negative points. Points within each grading criteria are cumulative. We added the scores for each of the criteria to get a final numerical score for each jurisdiction, which we then used to construct a curve and assign letter grades.

A good grade reflects a regulatory environment friendly to ADU construction. Jurisdictions with high scores do not impose excessive zoning and permitting barriers that could get in the way of ADU construction. A bad grade reflects a regulatory environment that places unnecessary and/or significant barriers in the way of homeowners constructing ADUs. Jurisdictions with low grades generally have burdensome regulatory requirements that restrict ADU construction despite the requirements of the state ADU ordinance.

1 Presumably, by following state standards, they deserve a good grade; but without the ordinance, we have insufficient evidence to assess their implementation.
2 Jurisdictions received extra credit for Parking Requirements for ADUs if they reduce parking barriers beyond what is required in CA ADU law. For example, not requiring parking for ADUs that are studios (with zero bedrooms) or allowing parking in tandem and/or setbacks. We also gave jurisdictions extra credit for Maximum Size for Attached and Detached ADUs if they did not include the language limiting the maximum size percent increase for either or both criteria. This is another indicator that the jurisdiction is reducing barriers to ADU development.