Accessory Dwelling Units (ADUs)

ADU Regulations Ordinance

The City's ADU regulations are identified in the following document which reflects Chapter 30.91 ADU Regulations: June 2025 Chapter 30.91 ADU Regulations

The City Council adopted the ADU Ordinance/Local Coastal Program Amendment on December 18, 2023: ADU Ordinance (12.18.23)

Following approval by the City Council, the Ordinance/LCPA was submitted to the California Coastal Commission (CCC) for certification. On March 13, 2025, the Coastal Commission conditionally certified the City's Ordinance/LCPA, which required the City to process an amending Ordinance/LCPA to accept CCC's required modifications.

On April 21, 2025, the City Council introduced the amending Ordinance. April 21, 2025 Item 9 Agenda Report.

On May 19, 2025, the City Council adopted the amending Ordinance. May 19, 2025 Item 6 Agenda Report

The adopted regulations became effective on June 12, 2025, the date CCC granted final certification approval.

Community Survey - ADUs for Low-Income Households

The City is exploring ways to create Accessory Dwelling Units (ADUs) for low-income households and is seeking community input. The City's certified 6th Cycle Housing Elements identifies a goal to create 15 ADUs that can be rented to low-income households by April 2029.

The City conducted a Community Survey to collect input to help us understand whether existing ADUs are being rented as affordable units and possible incentives to encourage creation of ADUs for rent to low-income households. Tenants qualify for affordable housing based on household income level.

Currently, the Area Median Income (AMI) for the San Diego region, effective April 16, 2025, is $130,800. The gross income for a low-income household does not exceed 80% of the Annual Median Income. This means a one-person household qualifies as low income with an income that does not exceed $92,700. An ADU is considered affordable for a one-person low-income household if the maximum monthly rent and utility costs do not exceed 30% of gross annual income, which in the case of a one person low-income household would be a maximum payment of about $2,318 monthly.

The information collected through this survey is solely for the purpose of assisting the City to meet its Housing Element commitments. It will not be used for any type of code enforcement action.

Staff expects to present the findings of the April/May 2025 community survey and seek City Council direction on next steps for potential modifications to these incentive programs at a future public meeting of the City Council, which we anticipate scheduling for a City Council meeting in August or September 2025.

What is an ADU? What is a JrADU?

As set forth in California Government Code section 65852.2, an Accessory Dwelling Unit (ADU) is a smaller (detached or attached) secondary dwelling unit with complete, independent living facilities (kitchen, bathroom, and access) that is located on the same parcel as a primary dwelling unit (existing or proposed). The ADU can be located within or attached to a single dwelling unit, within a multiple dwelling unit building, or in a separate detached structure.

As set forth in California Government Code section 65852.22, a Junior ADU (JrADU) is a small dwelling unit (500 square feet maximum in size) that is developed within the walls of a single dwelling unit (existing or proposed). The JrADU must have a separate entrance, efficiency kitchen, and access to a bathroom either within the JrADU or via shared access with the primary dwelling unit. A JrADU is allowed only within the single dwelling unit and is not permitted within an accessory structure or multiple dwelling unit development. JrADUs are only allowed on lots in single dwelling unit zones.

The State’s ADU regulations are complex. Guidance is provided by the California Department of Housing and Community Development (HCD) in the 2022 HCD ADU Handbook and the California Coastal Commission January 21, 2022 letter titled “Updates Regarding the Implementation of New ADU Laws” that was addressed to the Planning Directors of Coastal Cities and Counties. Some elements in the State’s ADU regulations and guidance are contradictory. For example, the Government Code provides different ADU standards for “single family” and “multifamily”, but does not provide a definition of what constitutes “multifamily”.

Consistent with local definitions, single dwelling unit lots with a maximum of one primary dwelling unit have a right to a maximum of one ADU and one JrADU per lot. Lots with multiple existing primary dwelling units (e.g. attached or unattached duplex) are allowed to have more than one ADU per lot in accordance with California Government Code Section 65852.2(e)(1)(C) and (D). This is consistent with the City’s definition of “multiple dwelling unit” per DMMC Section 30.04.130(F), which applies to a building or lot containing two or more dwelling units. This includes lots with multiple units located within a common building or that share a common wall and to lots with multiple detached units that do not share a common wall. Lots with existing multiple dwelling unit development have a right to two “detached” ADUs on the lot per Government Code Section 65852.2. However, to protect coastal access and coastal resources and harmonize with the Coastal Act, the City can use the applicable Coastal Development Permit findings for approval to accommodate such ADUs in a design where one or both of the ADUs is attached to its respective primary dwelling unit.

Determinations of allowable size of an ADU on a specific lot must account for site specific harmonizing between State ADU law and the Coastal Act as necessary to protect coastal access and coastal resources. Per State law, at a minimum the City must accommodate at least the size of an efficiency unit as defined by Health and Safety Code Section 18007 (Government Code Section 65852.2(c)(2)(A)); and maximum size of 850 square feet or 1,000 square feet for an ADU with more than one bedroom (Government Code Section 65852.2(c)(2)(B)). An attached ADU shall be limited to a maximum of 50% of the size of the primary dwelling unit if there is an existing primary dwelling unit (Government Code Section 65852.2(a)(1)(D)(iv)).

Prospective applicants are encouraged to contact the Planning Department for clarification on implementation.

Zones Where ADUs and JrADUs Are Permitted

ADUs are allowed in zones that allow single dwelling unit or multiple dwelling unit development. In Del Mar, this includes all of the City’s residential zones and the Carmel Valley Precise Plan Specific Plan (CVPP).

A lot with a single dwelling unit is permitted to have a maximum of one ADU and one JrADU. The JrADU must be located within the walls of the primary dwelling unit. In addition to the JrADU, one detached ADU is permitted within either a new detached structure or within an existing detached accessory structure that is converted to an ADU. Alternatively, a single dwelling unit lot is permitted to have either one ADU within the walls of the primary single dwelling unit or create one attached ADU within an addition to the primary single dwelling unit; however, in these two examples a JrADU would not be allowed. JrADUs are not allowed within a detached ADU and a maximum total of one ADU is allowed under all scenarios. The primary dwelling unit in all scenarios can be an existing or proposed structure.
An existing duplex (two units on one lot attached or unattached) is permitted to have a maximum of two ADUs per lot. The primary dwelling units must be existing. Each primary dwelling unit can have one ADU that is detached or attached from the primary dwelling unit per the development standards that are applicable to ADUs on lots with a single dwelling unit. . If necessary to protect coastal access and coastal resources, such ADUs may be accommodated in a design where one or both of the ADUs is attached to its respective primary dwelling unit however, the ADUs cannot be attached to each other. The City’s Coastal Development Permit findings may be used in this case to justify accommodation of attached ADUs in this scenario.
A lot with existing multiple dwelling unit development that includes three or more dwelling units (i.e. RM-South) is permitted to incorporate ADUs into spaces that are not located within the dwelling units themselves. This type of ADU may be constructed within existing multiple dwelling unit building spaces that are not associated with an individual dwelling unit (i.e. common area storage rooms, boiler rooms, attics, basements, or parking garages). The maximum number of ADUs in converted space of multi-dwelling unit buildings is 25 percent of the total number of existing dwelling units on the lot. In addition, up to two additional ADUs may be located on multiple dwelling unit lots as detached structures (maximum of two detached ADUs per lot).

JrADUs are allowed only in single dwelling unit zones, which within the City of Del Mar include the CVPP, R1-10, R1-10B, R1-14, R1-40, R1-5, and R1-5B zones. Only one JrADU is permitted per lot.

How to Apply

State law requires a streamlined, ministerial review process for proposed ADUs and JrADUs that exempts all such applications that meet each of the specified objective review standards from discretionary permit review, including design review.

Applicants will need to fill out an ADU Application Packet (Fillable PDF), pay associated fees (PDF), and submit development plan sets. Submitted applications will be processed in accordance with the City’s procedures for approval of administrative Coastal Development Permits per DMMC Section 30.75.080. Submitted plans that meet the requirements of Government Code Section 65852.2 will be approved within 60 days of a complete application submittal. If the ADU or JrADU permit application is processed at the same time as a permit application for a new primary dwelling unit on the lot, the City may delay acting on the ADU or JrADU application until the City acts on the permit application for the primary dwelling unit.

Benefits of ADUs/JrADUs

Can provide a greater balance of housing options and affordability to meet the City’s housing goals
Can provide more affordable housing options for seniors and lower-income individuals to remain in the community
Can provide independent accommodations for extended family or caregivers to live on the same premises
Can provide the opportunity for supplemental rental income to homeowners
Can help to reduce local vehicle miles of travel (VMT) and meet Climate Action Plan goals by accommodating a greater variety of housing options in close proximity to services and employers within the community