TO:
Honorable Planning Commission Chair and Commissioners
THROUGH:
Michael Codron, Interim Community Development Director
FROM:
Adam Finestone, AICP, Planning Manager
Jaehee Yoon, AICP, Senior Planner
Maricela Guillean, Associate Planner
SUBJECT:Title
Staff recommends that the Planning Commission conduct a study session to discuss and provide input on proposed rear yard setback regulations for accessory structures in single-family residential zones.
Body
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RECOMMENDATION:
Staff recommends that the Planning Commission conduct a study session to discuss and provide input on proposed rear yard setback regulations for accessory structures in single-family residential zones.
BACKGROUND
At the June 18, 2024, City Council meeting, the City Council requested a future agenda item to discuss the City’s existing rear yard setback requirements for accessory structures in the single-family residential (RS) zone. The concern stemmed from provisions that allow accessory structures in rear yards with zero side or rear setbacks. This regulation is codified in Manhattan Beach Municipal Code (MBMC) Section 10.52.050(D) (Relation to Property Lines), as provided in part below:
An accessory structure, any portion of which is located within a required rear yard, shall be located on a rear or interior side property line, or shall be not less than three feet (3 ′) from said property line(s).
For the purpose of this report, rear yard setbacks for accessory structures in the rear yard of a property shall be assumed to mean both the rear and interior side yard unless specifically stated otherwise.
On February 4, 2025, staff presented the agendized item before the City Council for discussion and was directed to further explore alternative setbacks and their implications and obtain the Planning Commission’s input.
On June 11, 2025, the Planning Commission conducted a study session (see Attachment 4 to this report) to discuss the item, which included background information on the purpose and history of the rear yard setback regulations, how these regulations have influenced existing development patterns, and the implications of eliminating the zero-foot setback allowance. During the meeting, questions were posed by the Commission on the impacts caused by accessory structures on shared property lines regarding diverted drainage patterns, grading and soil stability, and the frequency of code enforcement complaints related to maintenance of those structures, all of which are further discussed below. The Commission also expressed interest in exploring alternative side and rear yard setback requirements due to privacy, fire safety, and access concerns, and directed staff to report back with potential options for consideration.
DISCUSSION:
As mentioned during the first study session in June 2025, accessory structures built with a zero-foot rear yard setback are commonly found in single-family zones across the City. If the rear yard setback standards are changed to eliminate the zero-foot allowance, these structures will be reclassified as legal nonconforming, meaning they were built lawfully but no longer comply with current regulations. As nonconforming structures, future alterations or expansions to an accessory structure would be limited and subject to specific conditions outlined in MBMC Section 10.68.030 to limit the intensification of the nonconformity.
Potential Code Amendment Considerations to Accessory Structure Setbacks
Given the limitations of alterations or expansions to newly designated nonconforming accessory structures, the following pathways can be considered if the rear yard zero-foot setback allowance is to be eliminated from the MBMC. (Refer to Attachment 1 for illustrative diagrams conceptualizing the proposed options with various scenarios depending on whether or not the site is adjacent to an alley; and whether the accessory structure use involves a detached garage for alley lots.)
A. Alternative setback standards for new construction and additions
1. Side/rear setback
a. Eliminate the zero-foot rear yard setback allowance and retain the existing three-foot minimum rear yard setback requirement. MBMC Section 10.52.050(D) currently allows accessory structures to either be built at the property line or to maintain a minimum three-foot rear yard setback. The Planning Commission may consider eliminating the zero-foot rear yard setback allowance and retaining a three-foot minimum setback requirement for both new accessory structures and additions to existing. It should be noted that alley-loaded detached garages are required to be setback a minimum 5 feet from the rear property line per MBMC Section 10.64.110(C). Hence, this provision to retain the three-foot setback for such structures will only apply to the side yard.
b. Revise the rear yard setback requirement to four feet to align with setback requirements for accessory dwelling units (ADUs). The Planning Commission may consider increasing the side/rear setback requirements to four feet minimum, which is derived from the City’s ADU ordinance and is consistent with the state ADU law. This would apply to new accessory structures and additions to existing structures, further ensuring setbacks are consistent if such accessory structures are later converted to an ADU. Similar to the option above, the four-foot setback would only apply to the side yard for alley-loaded detached garages.
c. Consider alternative setback standards. The Planning Commission may consider adopting alternative rear yard setback standards other than three or four feet, as noted above. Neighboring cities such as Redondo Beach, Hermosa Beach, and El Segundo currently require setbacks ranging from three to five feet for accessory structures.
d. Potential exception(s) to amendments. As an exception to any change to rear yard setback requirements, the Commission may consider retaining an allowance for a zero-foot rear yard setback for residential properties immediately adjacent to commercially zoned lots. This would be applicable only to the side(s) of a residential lot that are immediately adjacent to a commercially zoned property and would be consistent with the zero-foot rear yard setback requirement for commercial properties.
2. Building separation
a. Revise building separation requirement from 10 feet to six feet. A reduction to the required building separation would help offset the added limitations from the potential increase to the side/rear setbacks. Because building separation requirements only apply to structures on the same lot, this change would give property owners more flexibility in how they configure structures on their lot without further impacting adjacent properties. The proposed six-foot building separation is also consistent with building code requirements and ensures that buildings can have openings such as operable windows and doors on those building faces.
B. Limitation of amended provisions to Area Districts 1 and 2
A vast majority of single-family zoned properties in the City are in Area Districts 1 and 2. As such, if the rear yard zero-foot setback is eliminated, most accessory structures that become legally nonconforming would be located in those area districts. Almost all single-family zoned properties in Area District 3 have alley access which reduces the potential impact of rear yard accessory structures with zero-foot setbacks. Additionally, Area District 3 generally has smaller minimum lot sizes and rear yard setback requirements for primary structures than Area Districts 1 and 2, thus minimizing the likelihood of rear yard accessory structures in that district. Area District 4 does not have any single-family zoned properties, so any amendment to the code related to accessory structure setbacks would not apply in that district. Further, because Area Districts 3 and 4 are in the Coastal Zone, any changes to provisions for those district would require an amendment to the City’s Local Coastal Program which must be certified by the California Coastal Commission to take effect.
C. Application processing for additions or alterations
If amendments to eliminate the zero-foot rear yard setback allowance are adopted, the existing process to allow additions and/or alterations to structures that become nonconforming could continue to be maintained. This would require either a ministerial or a discretionary application (i.e., Minor Exception) depending on the project scope as below:
a. Property owners who wish to construct an addition to or alter an existing legal nonconforming accessory structure may apply for a building permit, provided the addition complies with the revised rear yard setback and building separation requirements, and does not exceed 50 percent of the structure’s reconstruction valuation.
b. For improvements exceeding 50 percent valuation, property owners may utilize the Minor Exceptions provisions of the MBMC (Section 10.84.120) for “alterations and additions (enlargements) to existing, smaller legal nonconforming structures” through a Director-level discretionary review process with no public hearings. A more detailed discussion of the Minor Exception findings can be found in the June 11, 2025, Planning Commission staff report (Attachment 4).
D. Addition of new definitions or supplement existing definitions for further clarity
The existing definitions related to accessory structures could be augmented as part of the potential code amendment to assist in applying the provisions with more clarity. Possible definitions that could be amended or added include the following:
a. Detached/Attached Accessory Uses (Add)
b. Detached Accessory Structures (Add)
c. Detached Garage (Add)
d. Habitable and Non-habitable Structures (Add)
e. Guest House (or Accessory Living Quarters) (Amend MBMC Chapter 10.04)
f. Accessory Uses and Structures (Amend MBMC Section 10.08.070)
Drainage/Grading Issues for Accessory Structures
The Building and Safety Division is responsible for reviewing drainage and grading plans for accessory structures during the plan check process and verifying that construction is completed in compliance with the building code. In coordination with the Public Works Department, the Building and Safety Division reviews grading and drainage plans associated with a project to ensure stormwater is properly routed to the front of the property or, if needed, detained on-site through drainage systems that convey water away from structures and prevent runoff across property lines. Compliance with the plans is verified on-site during the construction process by City building inspectors. While drainage concerns are more likely to occur when accessory structures are built with a zero-foot setback, said concerns exist regardless of whether a setback is provided.
Maintenance Issues with Existing Accessory Structures
A public nuisance is defined in MBMC Section 9.68.020 to include a broad array of circumstances, including, but not limited to, any building that has dry rot, warping, termite or similar infestation. The Code Enforcement Division is responsible for determining if a structure constitutes a public nuisance and if a violation is confirmed, a Notice of Violation (NOV) or an administrative citation is issued to initiate abatement. In such instance, the Code Enforcement Division would encourage coordination and cooperation with neighboring property owners to conduct maintenance activities and address the NOV. As of the writing of this report, the Code Enforcement Division has not received any formal complaints of this specific nature. The Code Enforcement Division has observed that a more common issue involves the accumulation of debris and lack of maintenance within the three-foot setback between structures and property lines. The Planning Commission may wish to consider the potential for increased maintenance challenges when evaluating any amendments to setback requirements for accessory structures.
ENVIRONMENTAL REVIEW:
The City has reviewed the proposed study session for compliance with the California Environmental Quality Act (CEQA) and has determined that the activity is not a “Project” as defined under Section 15378 of the State CEQA Guidelines; therefore, pursuant to Section 15060(c)(3) of the State CEQA Guidelines, the study session is not subject to CEQA. Thus, no environmental review is necessary at this time. If specific code amendments are suggested, those amendments, if not exempt, will be reviewed as may be required by CEQA.
PUBLIC OUTREACH:
A courtesy notice for this meeting was emailed to all interested parties on August 19, 2025, and published in The Beach Reporter on August 21, 2025. Should amendments to the MBMC ultimately be considered by the Planning Commission and City Council, public notification in accordance with State and Municipal Code requirements will be conducted.
CONCLUSION:
Based on the June 11, 2025, Planning Commission meeting, staff has proposed a range of potential amendment considerations related to accessory structure setbacks. These include modified rear yard setback and building separation requirements, limited amendment scope and applicability, a simplified development application process, and added clarification for applicable definitions in the MBMC. Staff is requesting that the Planning Commission discuss the outlined options and direct staff to either schedule a public hearing for consideration of potential MBMC amendments related to accessory structure setback regulations in the single-family residential zone, or report back to the City Council if amendments are not recommended.
ATTACHMENTS:
1. Accessory Structure Diagrams
2. Existing Ordinance (MBMC Sections 10.04, 10.08 and 10.52.050)
3. City Council Meeting Staff Report and Minutes (February 4, 2025)
4. Planning Commission Meeting Staff Report and Minutes (June 11, 2025)