San Diego Municipal Code § 143.1315 Urban Lot Splits in a Single Dwelling Unit Zone

for Single Family Zones (“Multi-Dwelling Unit and Urban Lot Split Regulations for Single Family Zones” added 3-11-2022 by O–21439 N.S.; effective 4-10-2022.)

Family Zones

These regulations are intended to implement California Senate Bill 9 (2021-2022) and California Government Code Sections 65852.21, 66411.7 and 66452.6 by allowing the construction of multiple dwelling units in single-family zones and/or an urban lot split, as specified in this Division. These regulations specify when and how multiple dwelling unit development may be constructed in a base zone that permits single dwelling unit development, but not multiple dwelling unit development. These regulations also specify when and how a single premise may be split into two premises that can be developed and conveyed separately when located within a base zone that permits single dwelling unit development, but not multiple dwelling unit development. (“Purpose of the Multi-Dwelling Unit and Urban Lot Split Regulations for Single Family Zones” added 3-11-2022 by O–21439 N.S.; effective 4-10-2022.)

Dwelling Unit Zones

(a) This Division applies to premises located within a RS, RX, RT and Planned
District Zones that permits single dwelling unit development, but not multiple
dwelling unit development, except as prohibited in Section 143.1303(b).

(b) This Division is not applicable in the following circumstances:

(1) When the premises is located within any of the following:

(A) Prime farmland or farmland of statewide importance, as
defined pursuant to United States Department of Agriculture
land inventory and monitoring criteria, as modified for
California, and designated on the maps prepared by the
Farmland Mapping and Monitoring Program of the Department
of Conservation, or land zoned or designated for agricultural
protection or preservation by a local ballot measure that was
approved by the voters of that jurisdiction;

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(B) Wetlands;

(C) The Very High Fire Hazard Severity Zone, unless the
development complies with Chapter 7A of the California
Building Code, which mitigates wildfire exposure risk through
materials and construction methods;

(D) A hazardous waste site that is listed pursuant to California
Government Code Section 65962.5 or a hazardous waste site
designated by the Department of Toxic Substances Control
pursuant to Section 25356 of the California Health and Safety
Code, unless the State Department of Public Health, State
Water Resources Control Board, or Department of Toxic
Substances Control has cleared the site for residential use or
residential mixed uses;

(E) A delineated earthquake fault zone as determined by the State
Geologist in any official maps published by the California
State Geologist, unless the development complies with
applicable seismic protection building code standards adopted
by the California Building Standards Commission under the
California Building Standards Law (Part 2.5 (commencing
with Section 18901) of Division 13 of the Health and Safety
Code), and by the Development Services Department;

(F) Special Flood Hazard Areas, unless:

(i) The premises has been subject to a Letter of Map
Revision prepared by the Federal Emergency
Management Agency and issued to the local
jurisdiction; or

(ii) The premises meets Federal Emergency Management
Agency requirements necessary to meet minimum flood
plain management criteria of the National Flood
Insurance Program pursuant to Part 59 (commencing
with Section 59.1) and Part 60 (commencing with
Section 60.1) of Subchapter B of Chapter I of Title 44
of the Code of Federal Regulations.

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(G) A regulatory floodway as determined by the Federal Emergency Management Agency in any official maps published by the Federal Emergency Management Agency, unless the development has received a no-rise certification in accordance with Section 60.3(d)(3) of Title 44 of the Code of Federal Regulations. If an applicant is able to satisfy all applicable federal qualifying criteria in order to provide that the premises satisfies this subparagraph and is otherwise eligible for streamlined approval under this section, an application shall not be denied on the basis that the applicant did not comply with any additional City permit requirement, standard, or action that is applicable to that premises;

(H) The MHPA of the MSCP Subarea Plan;

(I) Environmentally Sensitive Lands conserved by dedication in
fee title, covenant of easement, or conservation easement; or

(J) A historical district that is a designated historical resource, or
on a premises that contains a designated historical resource.

(2) If the development requires demolition or alteration of any of the
following:

(A) A dwelling unit that is subject to a recorded covenant,
ordinance, or law that restricts rents to levels affordable to
persons and families of moderate income, low income, or very
low income.

(B) A dwelling unit that has been occupied by a tenant in the last
three years.

(3) If the premises contains SRO hotel rooms or other dwelling units that
were withdrawn from rent or lease in accordance with California
Government Code Sections 7060 through 7060.7 during the 15-year
period preceding the application.

(4) If the development requires the demolition of more than 25 percent of
the existing exterior structural walls of a dwelling unit, unless the
premises has not been occupied by a tenant in the last three years prior
to application submittal.
(“Application of Multi-Dwelling Unit and Urban Lot Split Regulations in
Single Dwelling Unit Zones” added 3-11-2022 by O–21439 N.S.; effective
4-10-2022.)

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(Amended 7-22-2024 by O-21836 N.S.; effective 10-5-2024.)

[Editors Note: Amendments as adopted by O-21836 N.S. will not apply within the Coastal Overlay Zone until the California Coastal Commission certifies it as a Local Coastal Program Amendment. Click the link to view the Strikeout Ordinance highlighting changes to prior language http://docs.sandiego.gov/municode_strikeout_ord/O-21836-SO.pdf ]

(a) An applicant seeking to utilize the provisions of this Division may use the multiple dwelling unit provisions of Section 143.1310, the urban lot split provisions of Section 143.1315, or a combination of both in compliance with the applicable regulations.

(b) An application to utilize the provisions of this Division may be denied if the
City makes a written finding based upon a preponderance of the evidence that
the development would have a specific, adverse impact upon public health and
safety or the physical environment and there is no feasible method to
satisfactorily mitigate or avoid the specific, adverse impact. A specific,
adverse impact means a significant, quantifiable, direct, and unavoidable
impact, based on objective, identified written public health or safety
standards, policies, or conditions as they existed on the date the application
was deemed complete. The following shall not constitute a specific, adverse
impact upon the public health or safety:

(1) Inconsistency with a zoning ordinance or land use plan designation.

(2) The eligibility to claim a welfare exemption under subdivision (g) of
Section 214 of the California Revenue and Taxation Code.

(c) This Division may be utilized in conjunction with Accessory Dwelling Unit
development consistent with the following regulations:

(1) An applicant utilizing only the multiple dwelling unit provisions of
Section 143.1310 and not the urban lot split provisions of
Section 143.1315 may construct two attached or detached Accessory
Dwelling Units in addition to the two dwelling units permitted in
accordance with Section 143.1310.

(A) The Accessory Dwelling Units shall comply with the
regulations in Section 141.0302, except that no more than two
Accessory Dwelling Units shall be permitted on the premises.

(B) Under no circumstances shall the total number of dwelling
units on the lot, inclusive of Accessory Dwelling Units, exceed
four.

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(2) An Accessory Dwelling Unit or Junior Accessory Dwelling Unit shall not be permitted on a premises that proposes to utilize or has utilized both the multiple dwelling unit provisions of Section 143.1310 and the urban lot split provisions of Section 143.1315.

(A) If an Accessory Dwelling Unit or Junior Accessory Dwelling
Unit exists on a premises that proposes to utilize the provisions
of both Section 143.1310 and 143.1315, the Accessory
Dwelling Unit must be removed or converted to one of the
multiple dwelling units permitted under Section 143.1310.

(B) Under no circumstances shall the total number of dwelling
units across the two lots resulting from Section 143.1315
exceed four.
(“Utilizing the Provisions of this Division” added 3-11-2022 by O–21439 N.S.;
effective 4-10-2022.)

A dwelling unit constructed in accordance with this Division shall not be rented for fewer than 31 days. (“Rental of Dwelling Units Constructed in Accordance with this Division” added 3-11-2022 by O–21439 N.S.; effective 4-10-2022.)

Up to two dwelling units may be permitted on a premises within a RS, RE, RX, RT or Planned District Zones that permits single dwelling unit development, but not multiple dwelling unit development, in accordance with the following regulations:

(a) The development regulations of the base zone in which the premises is located
shall apply, except as specified in this section:

(1) Density Regulations. The maximum permitted density shall be two
dwelling units per lot. The dwelling units may be attached to or
detached from one another, provided that the structure(s) meet
California Building Code safety standards and are constructed
sufficiently to allow separate conveyance.

(2) Setback Regulations

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(A) No setback is required for an existing structure that is
converted to a dwelling unit. In addition, a dwelling unit that is
constructed in the same location and within the same building
envelope as an existing structure may continue to observe the
same setbacks as the structure it replaced.

(B) Except as provided in Section 143.1310(a)(2), dwelling units
must comply with the front yard and street side yard setbacks
of the base zone. Interior side yard and rear yard setbacks for
dwelling units shall be provided as follows:

(i) One-story dwelling units with a structure height of
16 feet or less may have zero setbacks in the interior
side yards and rear yards.

(ii) One-story dwelling units with a structure height that
exceeds 16 feet and multi-story dwelling units may
have zero setbacks in the interior side yards and rear
yards, unless the side or rear property line abuts
another premises that is residentially zoned or
developed with exclusively residential uses, in which
case a 4-foot setback shall apply.

(3) Parking Regulations

(A) Within a Sustainable Development Area or transit priority area, no off-street parking spaces are required.

(B) Outside of a Sustainable Development Area or transit priority
area, off-street parking spaces shall be provided as follows:

(i) One off-street parking space per dwelling unit shall be
required for the construction of the third and fourth
dwelling units. Off-street parking spaces are not
required for the first two dwelling units.

(ii) Within the Beach Impact Area of the Parking Impact
Overlay Zone, one off-street parking space shall be
required per dwelling unit unless the applicant can
demonstrate to the satisfaction of the City Manager that
there is access to a car share or other shared vehicle
within one block of the premises.

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(4) Transportation Amenities

(A) Within a Sustainable Development Area and within the Beach
Impact Area of the Parking Impact Overlay Zone, residential
development, including an urban lot split under Section
143.1315, shall be required to provide transportation amenities
based on the Transportation Amenity Score in accordance with
Section 142.0528. Transportation amenity means a feature
provided by a development that reduces vehicle trips by
informing, educating, and incentivizing transit use, bicycling,
walking, and ridesharing. The types of transportation amenities
are listed in the Land Development Manual Appendix Q.

(B) The applicant shall be required to provide transportation
amenities on each lot with new residential dwelling units.

(5) Landscape Regulations

(A) Two trees shall be provided on the premises for every 5,000 square feet of lot area, with a minimum of one tree per premises. This regulation can be met by existing trees on the premises. If planting of a new tree is required to comply with this section, the tree shall be selected in accordance with the Landscape Standards of the Land Development Manual and the City’s Street Tree Selection Guide.

(B) If development would result in more than two dwelling units
within the two premises permitted by this Division, then
compliance with the street tree regulations pursuant to
Section 142.0409 is required.

(6) Dwelling units constructed within Areas of Future Sea Level Rise
must comply with the regulations in Section 132.0404.

(7) Development Impact Fees for development constructed in accordance
with this Division shall comply with Section 142.0640(b).

(8) Dwelling units shall comply with the wetlands regulations in
Section 143.0141(b), the sensitive coastal bluff regulations in
Section 143.0143, the coastal beaches regulations in Section 143.0144,
and the Supplemental Regulations of the Coastal Overlay Zone in
Section 132.0403.

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(b) Notwithstanding Section 143.1310(a), a second dwelling unit with a maximum gross floor area of 800 square feet shall be permitted on a premises with an existing or proposed dwelling unit, regardless of non-compliance with one or more development regulations. The development shall comply with the floor area ratio of the underlying base zone unless the development incorporates an existing structure that exceeds the allowable floor area ratio or is under the allowable floor area ratio by less than 800 square feet, in which case a second dwelling unit that does not exceed 800 square feet shall be permitted. (“Construction of Multiple Dwelling Units in a Single Dwelling Unit Zone” added 3-11-2022 by O–21439 N.S.; effective 4-10-2022.) (Amended 3-7-2023 by O-21618 N.S.; effective 5-6-2023.) (Amended 8-5-2024 by O-21843 N.S.; effective 9-12-2024.) (Amended 7-22-2024 by O-21836 N.S.; effective 10-5-2024.)

[Editors Note: Amendments as adopted by O-21836 N.S. will not apply within the Coastal Overlay Zone until the California Coastal Commission certifies it as a Local Coastal Program Amendment. Click the link to view the Strikeout Ordinance highlighting changes to prior language https://docs.sandiego.gov/council_reso_ordinance/rao2024/O-21843.pdf

(Amended 12-18-2024 by O-21905 N.S.; effective 2-6-2025.)

[Editors Note: Amendments as adopted by O-21905 N.S. include additional amendments applicable within the Coastal Overlay Zone, including text amendments.] Click the link to view the Ordinance and Strikeout highlighting changes https://docs.sandiego.gov/council_reso_ordinance/rao2024/O-21905.pdf

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An urban lot split is a lot split that divides an existing single premises into no more than two separately conveyable premises in a zone that allows single dwelling unit development, but not multiple dwelling unit development, and may be permitted, subject to the following regulations:

(a) An urban lot split shall be permitted in accordance with a Process One parcel
map and shall comply with Chapter 14, Article 4, Division 2, except that
dedications of public rights-of-way or the construction of offsite
improvements for the parcels being created and the correction of
nonconforming development regulations of the base zones are not required.

(b) The expiration of the subdivision shall be in accordance with Government
Code Section 66452.6.

(c) The urban lot split provisions of this section may not be used if any of the
following apply:

(1) The lot was established through a prior urban lot split in accordance
with this section. A lot may only be split once in accordance with this
section. Lots created pursuant to this section are ineligible for any
further subdivision.

(2) The record owner or any person acting in concert with the record
owner has previously subdivided an adjacent lot using an urban lot
split in accordance with this section.

(d) Only residential uses are permitted on a lot that was created by the urban lot
split provisions of this section.

(e) Prior to the recordation of the parcel map, the record owner shall sign an
affidavit acknowledging the record owner intends to reside in one of the
dwelling units as their primary residence for a minimum of three years from
the date of the approval of the urban lot split. The affidavit shall be in a form
that is approved by the City and recorded in the Office of the County
Recorder. This requirement shall not apply to a record owner that is a
community land trust, as defined in California Revenue and Taxation Code
Section 402.1(a)(11)(C)(ii), or is a qualified nonprofit corporation as
described in California Revenue and Taxation Code Section 214.15.

(f) The development regulations of the base zone in which the lot is located shall
apply, except as specified in Section 143.1310(a) and this section.

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(1) The minimum lot area and minimum lot dimensions regulations of the
base zone shall not apply and are replaced with the following
regulations:

(A) The two lots shall be approximately equal in size, provided that
one lot shall not be smaller than 40 percent of the lot area of
the original lot.

(B) The two lots shall each be no smaller than 1,200 square feet.

(C) If the lot contains existing structures that will remain as part of
the development, the lot shall be split in a manner that complies
with or comes as close as possible to compliance with the floor
area ratio of the underlying base zone, consistent with
Section 143.1315(f)(1)(A) and (B).

(2) A lot should be subdivided in a manner that complies with the street
frontage and driveway width requirements of the base zone wherever
feasible. Development that does not comply with the street frontage
and driveway width requirements of the base zone shall record an
access easement on the lot to the satisfaction of the City Engineer.

(g) Notwithstanding Section 143.1315(f), an urban lot split and construction of a
second dwelling unit with a maximum gross floor area of 800 square feet
shall be permitted on each of the lots created by an urban lot split, regardless
of non-compliance with one or more development regulations, subject to the
following:

(1) The development shall comply with the floor area ratio of the
underlying base zone unless the development incorporates an existing
structure that exceeds the allowable floor area ratio or is under the
allowable floor area ratio by less than 800 square feet, in which case a
second dwelling unit that does not exceed 800 square feet shall be
permitted.

(2) The development shall comply with the lot size requirements in
Section 143.1315(f)(1).

(3) Within the Coastal Overlay Zone, development shall comply with the
wetlands regulations in Section 143.0141(b), the sensitive coastal bluff
regulations in Section 143.0143, the coastal beaches regulations in
Section 143.0144, and the Supplemental Regulations of the Coastal
Overlay Zone in Section 132.0403.

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(h) Within the Coastal Overlay Zone, the following apply to urban lot splits
outside of Special Flood Hazard Areas and within an area of future sea level
rise (within a 75-year horizon) as determined by the City Manager based on
the most current sea level rise vulnerability maps:

(1) The urban lot split shall comply with the regulations in Section
143.0146(b) and if applicable, Section 143.0146(g). The base flood
elevation utilized, and the applicability of Section 143.0146(g), shall be
based on the FIRM Zone of the Special Flood Hazard Area in closest
proximity to the premises on which the dwelling unit is proposed.

(A) Hard shoreline armoring shall not be constructed to protect the
lot from the effects of sea level rise.

(B) The record owner of the urban lot shall, in a form that is
approved by the City Manager, acknowledge the following:

(i) The urban lot split is located in an area of future sea
level rise that may become hazardous in the future:

(ii) Sea level rise could render it difficult or impossible to
provide services to the premises;

(iii) The boundary between public land (tidelands) and
private land may shift with rising seas and the
development approval does not permit encroachment
onto public trust land;

(iv) Additional adaptation strategies may be required in the
future to address sea level rise, consistent with the
Coastal Act and certified Local Coastal Program; and

(v) The record owner shall waive any rights under Public Resources Code Section 30235 and related Local Coastal Program policies to any hard shoreline armoring to protect the lot. (“Urban Lot Splits in a Single Dwelling Unit Zone” added 3-11-2022 by O-21439 N.S.; effective 4-10-2022.) (Amended 8-5-2024 by O-21843 N.S.; effective 9-12-2024.)

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Article 3: Supplemental Development Regulations