To: Sonoma County Board of Supervisors
Department or Agency Name(s): Permit Sonoma
Staff Name and Phone Number: Tennis Wick, Director (707) 565-1925 and Eric Gage, Planner III (707) 565-1391
Vote Requirement: Informational Only
Supervisorial District(s): Countywide
Title:
Title
Status Report on Accessory Dwelling Unit (ADU) Production, Policies and Programs
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Recommended Action:
Recommended action
Receive an informational update on the status of the unincorporated county’s Accessory Dwelling Unit (ADU) development, and related policies and programs.
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Executive Summary:
This item presents an informational update on the status of Accessory Dwelling Unit (ADU) development and related policies and programs in the Sonoma County General Plan Housing Element and Sonoma County Code (Section 26-88-060).
Discussion:
Accessory dwelling units (ADUs) are complete dwelling units with full kitchens and bathrooms, located on lots with a primary single-family or multi-family residence. Also referred to as in-law units or second units, ADUs have become increasingly popular and an important source of housing production within the County and across the State in recent years. The County’s General Plan Housing Element 2023-2031, the blueprint for housing development in the County, identifies ADUs as a key form of housing for lower- and moderate-income households and also identifies ADU development as a key strategy for meeting the County's RHNA obligation for these income levels. The Housing Element also outlines several policies and programs the County must implement to incentivize ADU development. This item outlines the role of ADUs in meeting the County’s State-mandated housing goals and presents an update on the status of ADU development and implementation of ADU policies and programs.
Regional Housing Needs Allocation (RHNA)
The Regional Housing Needs Allocation (RHNA) is the number of housing units that each jurisdiction is responsible for developing during the Housing Element cycle from 2023 to 2031. The County’s RHNA is 3,824 units. Jurisdictions are allowed to forecast the number of ADU permits anticipated during the Housing Element cycle based on the average historical permitting rate and apply the number of ADUs to fulfill their RHNA obligations.
In recent years, the County has permitted ADUs at a higher rate than most jurisdictions countywide. The annual average of permits issued for ADUs for the period from 2018 to 2022 was 102 permits per year. Because of the County’s high annual rate of ADU permitting, the forecasted ADU development for the 8-year housing element cycle is 816 ADUs in total. The Association of Bay Area Governments (ABAG) prepared affordability rates for Bay Area jurisdictions to apply to forecasted ADU construction, with 30% for very low-income, 30% for low-income, 30% for moderate-income and 10% for above-moderate income. Therefore, 489 forecasted ADUs are counted against the County’s 1,608-unit RHNA obligation for low- and very low-income units, making up roughly 30% of the total. In 2023, the County permitted 120 new ADUs and construction on 114 new ADUs was completed. This data is available on the State Department of Housing and Community Development’s (HCD) Annual Progress Report Data Dashboard <https://www.hcd.ca.gov/planning-and-community-development/housing-open-data-tools/housing-element-implementation-and-apr-dashboard>.
The California Department of Housing and Community Development (HCD) has indicated that the ADU affordability rates developed by ABAG may be used through 2025 but following 2025 the affordability rates assumed must be reassessed based on more current data. To collect the necessary data to update the affordability rates for 2026, ABAG created an online survey for new ADU owners to report their approximate monthly rent and affordability levels. This survey will be voluntary for County ADU permit holders.
Housing Element Programs
Among the County’s Housing Element’s 95 implementation programs and subprograms, several subprograms support ADU development and preservation.
Subprogram #25a: Permit Sonoma maintains the ADU webpage <https://permitsonoma.org/regulationsandinitiatives/housingtypes/accessoryunitsandjuniorunits/accessorydwellingunits> with extensive information on ADU permitting requirements, procedures, and other resources for property owners interested in developing an ADU.
Subprogram #25b: The County has received support from the Napa Sonoma ADU Center <https://napasonomaadu.org/>, which provides resources and support to interested property owners, and maintains a gallery of pre-reviewed ADU plans available to the public. With the ADU Center’s grant funding having ended in FY 23-24, Permit Sonoma is evaluating other options for non-profit support. New state legislation requires local jurisdictions to maintain pre-approved ADU plan sets available to the public, described in more detail under subprogram #25e.
Subprogram #25c: New laws and incentives for ADU development, such as state grants, are publicized on the Permit Sonoma webpage and the housing newsletter, sent by email to the list of interested recipients established through public engagement for the Housing Element update.
Subprogram #25d: Permit Sonoma administers ADU Rescue, a penalty postponement program that allows owners of unpermitted ADUs to postpone enforcement penalties for a period of up to five years if the unit meets basic habitability requirements.
Subprogram #25e: New State legislation requires jurisdictions to maintain an online list of pre-approved ADU plan sets for use by the public by 2025. Coordination between Permit Sonoma and cities is ongoing to identify interested architects with ADU plans, to perform plan checks for consistency with current building code requirements, and to publish a consolidated list of available plan sets. Going forward, County jurisdictions may cooperate to add new plan sets to the list for use countywide.
Subprogram #25f: Permit Sonoma will develop a list of property owners renting accessible ADUs to people with disabilities on a project-by-project basis as permits for development of accessible ADUs are issued by Permit Sonoma. The list will be used to refer people with disabilities to accessible ADUs available for rent. Non-profit partners may be identified in the future to provide additional support to implement this program.
Subprogram #25g: This subprogram directs Permit Sonoma to establish a monitoring program to track affordability levels for new ADUs every two years, which may be accomplished by regional surveys. As described above, ABAG’s online survey for new ADU owners to report their approximate monthly rent and affordability levels would meet the intent of this program. The County intends to make the online affordability survey optional for ADU permit holders. If annual ADU construction does not meet the forecasted development in the County’s Housing Element based on the first two years of tracking data, Permit Sonoma must establish additional incentives to achieve the forecasted affordability goals.
Local ADU Regulations
In December 2023, the Board of Supervisors adopted revisions to the County’s ADU ordinance that were needed for consistency with State law and the HCD’s published guidance. The most significant revision to the County’s local ordinance (Sonoma County Code Section 26-88-060) was the allowance for up to two ADUs on a parcel with an existing or proposed single-family residence: one ADU attached to a single-family dwelling, and a second detached ADU. The ordinance previously permitted only one ADU on a parcel with a single-family residence, consistent with State law then in effect. The code update also increased the allowance for up to two ADUs on a property with a multifamily residence, as required by State law. There were no changes to Junior ADU code provisions, which allow existing space in a single-family dwelling to be converted to a JADU, in addition to other ADU allowances.
State Law
Government Code section 66342 (commonly known by its bill number, AB 1033), effective January 1, 2024, gives local jurisdictions the option to adopt an ordinance to allow the separate ownership and sale of the primary dwelling unit and an accessory dwelling unit as condominiums. Permit Sonoma staff will continue to monitor and evaluate California jurisdictions implementing this optional legislation.
Strategic Plan:
N/A
Racial Equity:
Was this item identified as an opportunity to apply the Racial Equity Toolkit?
No
Prior Board Actions:
December 5, 2023 <https://sonoma-county.legistar.com/LegislationDetail.aspx?ID=6437914&GUID=857F14EC-AFF9-4419-B098-F8A3691521E0&Options=&Search=> - Board adopted Ordinance No. 6458, updating the Zoning Code’s ADU regulations.
Fiscal Summary
Narrative Explanation of Fiscal Impacts:
There are no fiscal impacts associated with this informational item.
Narrative Explanation of Staffing Impacts (If Required):
There are no fiscal impacts associated with this informational item.
Attachments:
None.
Related Items “On File” with the Clerk of the Board:
None.