Article I — TWO-UNIT DEVELOPMENT

The purpose of this Article is to allow up to two detached or attached primary housing units on one parcel, establish objective standards, and regulate subdivision of parcels in single-family zoned areas in accordance with state law. This Chapter shall be implemented and interpreted in conjunction with California Government Code  Sections 65852.21  and 66411.7  , as amended, and applicable objective standards contained within Titles 26 and 27 of the San Mateo Municipal Code.

For the purposes of this Chapter, the following definitions apply. Terms not defined herein shall rely upon the definitions contained in Title 26 and Title 27 of the San Mateo Municipal Code.

(a) "Access Corridor" means an access easement or the 'pole' of a flag lot that provides vehicular access to the right-of-way. Access corridors shall consist of paving and be free of landscaping or other permanent features that obstruct ingress/egress and vehicular traffic to a parcel.

(b) "Acting in concert" means that the owner, or a person acting as an agent or representative of the owner, knowingly participated with another person in joint activity or parallel action toward a common goal of subdividing the adjacent parcel.

(c) "Car Share Facility" means one or more parking space(s) that have been designated permanently for car share vehicles, where the vehicles are leased for short periods of time, often by the hour.

(d) "Department" means the Department of Community Development.

(e) "Existing Exterior Structural Wall" means and constitutes the original bottom plate and original top plate in its existing position, original studs (with the exception for new window framing), and capable of standing without support.

(f) "Flag or Panhandle Lot" means a parcel which includes a strip of land that is owned in fee that is used primarily for vehicular access from a public or private street to the major portion of the parcel. For the purposes of determining setbacks, the property line parallel to the primary right-ofway and part of the major portion of the parcel shall be the front property line. Maximum floor area ratio (FAR) shall be based on the gross square footage of the parcel.

(g) "High Quality Transit Corridor" means a corridor with fixed bus route service with service intervals no longer than 15 minutes during peak commute hours.

(h) "Major Transit Stop" means a site containing any of the following: (i) an existing rail or bus rapid transit station; (ii) a ferry terminal served by either a bus or rail transit service; or (iii) the intersection of two or more major bus routes with a frequency of service intervals of 15 minutes or less during the morning and afternoon peak commute periods.

(i) "Primary Unit" (also called a residential dwelling unit or residential unit) means a singlefamily residence or a residential dwelling unit within a multifamily residential development. A primary unit is distinct from an ADU or junior accessory dwelling unit (JADU), and may be a single-family residence (i.e. one primary unit) or a duplex (i.e. two primary units detached or attached).

(j) "SB 9 Dwelling Unit or SB 9 Unit" means a primary unit that is developed pursuant to the requirements of this Article, applicable San Mateo Municipal Code provisions, and Government Code  Sections 65852.21  and 66411.7  , as amended.

(k) "SB 9 Project or SB 9 Planning Application" means a project application submitted to the City in accordance with this Article, SB 9, and applicable San Mateo Municipal Code provisions to do one or more of the following:

(1) Split a qualifying single-family residentially zoned parcel into two lots; or

(2) Develop no more than two primary units on a single lot, or

(3) When a lot is subdivided, develop no more than two dwelling units, inclusive of ADUs and JADUs, on a single parcel.

(l) "Senate Bill 9 or SB 9" means the state law signed by the Governor into law on September 19, 2021 that amended Government Code  Sections 65852.21  and 66411.7  to allow up to two primary units on and/or lot splits of qualifying single-family zoned parcels.

(m) "Substantial Removal" means the demolition of 50% or more of a structure's exterior walls (measured in linear feet) and/or roof (measured in square feet). Existing exterior walls that are converted to interior walls shall be counted as walls to be demolished. For the purposes of this Chapter, substantial removal for a roof shall not apply to permit applications for re-roofing where roof pitch alterations do not exceed an increase in height of more than two (2) feet as measured at the highest point or where a SB 9 planning application has been submitted as part of the proposed improvements. Doors, including garage doors, entry doors, and sliding glass doors, shall not be included in the percentage calculation of an existing structure's exterior walls. This section shall not apply to an accessory building or to a residence that has been declared a public nuisance under this Code.

(n) "Sufficient to Allow Separate Conveyance" means that connected or adjacent units can be sold separately if they conform to condominium standards to allow for the adequate transfer of title, ownership, rights, and interests in the property from one entity to another.

(o) "Urban Lot Split" means a subdivision of an existing legal single-family zoned parcel into no more than two separate single-family zoned parcels that meet all of the criteria and standards set forth in this Chapter, applicable objective standards of San Mateo Municipal Code Title 26, and Government Code  Sections 65852.21  and 66411.7  , as amended.

(Ord. No. 2022-10 § 1.) Cross References Section 27.21.130(b)

27.21.030 Rules of Procedure

Except as otherwise outlined below, the applicable rules of procedure contained in Chapter 27.08 shall apply to all SB 9 planning applications. Where there is a conflict, standards in this Chapter shall prevail.

(a) Planning Application Submittal. An SB 9 planning application, on the form(s) prescribed by the Department, for either an attached or detached unit(s) and/or urban lot splits, shall be submitted for all development pursuant to the provisions of this Chapter.

(1) An applicant may file concurrent planning applications under this Chapter for one or two-unit development and an urban lot split.

(2) Processing of Applications. Unless an SB 9 application is submitted pursuant to Section 27.21.045 of this Chapter, SB 9 application(s) shall be processed as prescribed in Section 27.08.040 of the San Mateo Municipal Code, except that these applications shall be considered ministerially with no public hearing.

(b) Informational Notice. Upon receipt of an SB 9 planning application, and once the project is deemed complete, the City shall provide an informational notice that an SB 9 application has been filed with the City to all property owners and tenants within a 500-foot radius of the subject parcel and to the applicable neighborhood association(s) in accordance with the noticing procedures adopted by the Department.

(c) Ministerial Permit Approval. If an SB 9 planning application complies with the provisions of this Chapter, a ministerial, non-discretionary permit shall be issued. Notwithstanding anything contrary in this code, the issuance of a ministerial SB 9 Two-Unit Development permit and/or a SB 9 Urban Lot Split permit is not appealable.

(d) Submittal Requirements. In addition to the requirements of Section 27.08.010(c), each application shall be accompanied by all of the following:

(1) Application Forms. Completed SB 9 planning application forms as prescribed by the Department;

(2) Property Ownership. Verification of property ownership in the form of a preliminary title report that is no more than a year old, showing the current owners of the property, the names of record owners of the land, and all existing easements and other reservations, restrictions, or covenants; and

(3) Legal Description. An accurate legal description of the property and any resultant lots in the case of an urban lot split application; and

(4) Plans. Scaled and accurate plans to include required applicable information as outlined in the Planning Application and/or Urban Lot Split Submittal Requirements checklists; and

(5) Affidavit. A completed property owner tenant disclosure affidavit and acknowledgement that the application meets SB 9 eligibility requirements.

(6) Findings. Findings of Approval. An SB 9 application not submitted pursuant to Section 27.21.045 of this Chapter shall be approved ministerially if the Zoning Administrator or designee makes all the following findings:

(A) The parcel is within the Two-Unit Overlay District and meets all qualifying criteria as outlined in this Chapter;

(B) The development meets all applicable objective standards contained in and required by the General Plan, San Mateo Municipal Code or other City adopted plans, policies, or standards;

(C) The development does not adversely affect matters regarding police protection, crime prevention, and security because it adheres to the objective standards of Chapter 23.54;

(D) The proposed SB 9 unit(s) is consistent with all applicable SB 9 objective design standards of the Two-Unit Overlay District

(7) Findings of Denial. An SB 9 application shall be denied if the Building Official makes written findings, based upon a preponderance of evidence, that:

(A) The proposed housing development would have a specific adverse impact, as defined and determined in paragraph (2) of subdivision (d) of Section 65589.5  , as amended, of the Government Code  , upon public health and safety or the physical environment, and for which there is no feasible method to satisfactorily mitigate or avoid the specific adverse impact(s).

(Ord. No. 2023-12 § 5; Ord. No. 2022-10 § 1.)

Cross References

Section 27.21.110

Section 27.21.110(d)

A deed restriction shall be submitted in a form approved by the City and recorded to run with the land for all development pursuant to this Article as indicated below:

(a) Prior to the issuance of any building permit(s), development pursuant to this Chapter shall require a deed restriction to be recorded requiring a prohibition of the establishment of short- term rentals and a requirement that a rental or lease of any dwelling unit created pursuant to this Chapter shall be for a period of at least 30 consecutive days.

Projects that do not meet the provisions of this Chapter shall be subject to either a Single-Family Dwelling Design Review (SFDDR) or Site Plan and Architectural Review (SPAR) discretionary review process.

(a) In no case shall an application for discretionary review:

(1) Propose to increase FAR above that permitted by the underlying zoning district, except to the extent allowed by state law; or

(2) Propose to further subdivide a parcel that had been established through a previous urban lot split pursuant to Government Code  Sections 65852.21  and 66411.7  , as amended; or

(3) Propose to increase the maximum number of permitted dwelling units; or

• (4) Propose a parcel size smaller than 1,200 sq. ft.; or

(5) Propose less than one parking space per unit unless otherwise allowed per Section 27.21.070 of this Chapter.

(Ord. No. 2022-10 § 1.) Cross References Section 27.21.030(a)(2) Section 27.21.030(d)(6) Section 27.21.070(a)(2)

The following lands classified as R1-A, R1-B, and R-C are not subject to the Two-Unit Development Overlay District:

(a) Any parcel that would require the demolition or alteration of any of the following housing types:

(1) Housing that is subject to a recorded covenant, ordinance, or law that restricts rents to levels affordable to persons and families of moderate, low, or very low incomes; or,

(2) Housing that is subject to any form of rent or price control through a public entity's valid exercise of its police power; or,

(3) Housing that has been occupied by a tenant within the last three years; or,

(4) A parcel(s) on which an owner of residential real property has exercised the owner's rights under Government Code  Chapter> 12.75 (commencing with Section 7060) of Division 7 of Title 1 (Ellis Act) to withdraw accommodations from rent or lease within 15 years prior to an SB 9 application submittal.

(b) On any parcel designated an historic district or property, or located in a resource or hazard area such as high fire areas, wetlands, fault zones, hazardous waste sites or lands under conservation easements per Government Code  Sections 65913.4(a)(6)(B-K)  , as amended.

(Ord. No. 2022-10 § 1.)

Cross References Section 27.21.110(a)(3)

For properties that develop a project pursuant to this overlay, the following limitations apply:

(a) A maximum of four units, with a maximum of two primary dwelling units (attached or detached), except as outlined in Article II below.

(b) Limitation on Rental.

(1) Short Term Rentals Prohibited. No dwelling unit created pursuant to this Chapter shall be rented for a period of less than 30 consecutive days as a short-term rental as set forth in Chapter 5.66. Rentals longer than 30 consecutive days are permitted.

(c) Limitation on Sale.

(1) If two or more primary units exist on a single parcel, they shall not be sold separately until an urban lot split application has been approved by the City and a final parcel map recorded.

(d) Limitation on Use.

(1) Lots created pursuant to Article II of this Chapter shall be limited to residential uses only.

SB 9 units, as defined in this Chapter, shall comply with the following development standards:

(a) Demolition Limits. SB 9 projects that do not involve an urban lot split are subject to the following:

(1) Demolition of less than 50% of a structure's exterior structural walls or roof shall be subject to a ministerial review process.

(2) Demolition of 50% or more of a structure's exterior structural walls or roof may be permitted subject the Alternative Discretionary Review process listed in Section 27.21.045 of this Chapter and issuance of a Special Use Permit for the substantial removal of the existing structure pursuant to Section 27.18.035 of the San Mateo Municipal Code.

(b) Maximum Floor Area Ratio. The maximum Floor Area Ratio (FAR) for all structures on site shall be determined by the underlying zoning district with the following exceptions:

(1) Application of development standards of the underlying zoning district shall not preclude the construction of up to two primary dwelling units nor physically preclude either of the two units from being at least 800 square feet in floor area.

(2) SB 9 unit(s) in excess of 800 square feet shall be subject to a Single-Family Dwelling Design Review (SFDDR) or Site Plan and Architectural Review (SPAR) discretionary review process and shall be governed by the maximum floor area established by the underlying zoning district.

(3) In instances where the existing floor area allowance of a lot has been fully utilized, an SB 9 unit of up to 800 square feet in size with at least 4-foot side and rear yard setbacks and up to 16-feet in height shall be permitted, unless the proposed development would have a specific adverse impact, as defined and determined in paragraph (2) of subdivision (d) of Section 65589.5  , as amended, of the Government Code  , upon public health and safety or the physical environment, and for which there is no feasible method to satisfactorily mitigate or avoid the specific adverse impact(s).

(c) Height. The specific height maximums outlined below are applicable to all zoning districts subject to the Two-Unit Development Overlay District:

(1) Attached SB 9 Units. The maximum building height is 24 feet to top of plateline and 32 feet to roof peak as measured from existing grade.

(2) Detached SB 9 Units. Maximum building height is 16 feet to top of plateline and 24 feet to roof peak as measured from existing grade.

(d) Setbacks. SB 9 unit(s) shall have setbacks as follows:

(1) Front Setback. A minimum setback from the front lot line, as required by the lot's underlying zoning district.

(2) Side and Rear Setbacks. A minimum setback of four (4) feet shall be required from the side and rear lot lines.

(3) No setback shall be required for an existing legally permitted structure that is converted into an SB 9 unit or a structure constructed in the same location and to the same dimensions as an existing legally permitted structure.

(e) Parking.

(1) General Requirements. There shall be a minimum of one standard size off-street parking space (either uncovered or covered) for each SB 9 unit. All parking, whether required or voluntary, shall be located entirely on the same lot as the dwelling unit it serves and shall conform to the size requirements of the City's "Standard Drawings and Specifications" as adopted by resolution of the City Council and on file with the Department of Public Works. Covered parking shall meet all applicable setbacks of the underlying zoning district.

(2) Exemptions. No off-street parking shall be required for an SB 9 unit in the following instances:

(A) The parcel is located within one-half mile walking distance of a high-quality transit corridor, as defined in Public Resources Code Section 2155(b)  ; as amended; or

(B) The parcel is located within one-half mile walking distance of a major transit stop, as defined in Public Resources Code Section 21064.3(e)  , as amended; or,

(C) The parcel is located within one block of a car share facility.

(f) Objective Design Standards.

(1) New residential construction of primary units subject to streamlined ministerial approval shall comply with the Interim Objective Design Standards as adopted by City Council resolution and as may be amended from time to time by further City Council resolution.

(g) Other Development Standards.

(1) All development pursuant to this Chapter shall also be subject to the requirements of the California Building Code, Fire Code and local fire sprinkler ordinance requirements.

(2) All objective standards of the underlying zoning district, Titles 27 and 23 and other relevant Titles of the San Mateo Municipal Code shall apply. If such standards conflict with this Chapter, the standards in this Chapter shall prevail. In no instance shall any objective building or design standard preclude the development of at least two primary dwelling units of at least 800 square feet each in size, unless the development would have a specific adverse impact, as defined and determined in paragraph (2) of subdivision (d) of Section 65589.5  , as amended, of the Government Code  , upon public health and safety or the physical environment, and for which there is no feasible method to satisfactorily mitigate or avoid the specific adverse impact(s).

(Ord. No. 2022-10 § 1.) Cross References Section 27.21.045(a)(5) Section 27.21.140

Section 27.21.140(e)(1)