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Title 27 — ZONINGChapter 27.21 — TWO-UNITArticle II — URBAN LOT SPLITS

§ 27.22

San Mateo Zoning Code · 2026-06 edition · updated 2026-07-25 · San Mateo

27.22.010 PERMITTED USES.

Use of buildings or land in this district and buildings hereafter erected, structurally altered or enlarged, shall be limited to the following:

(a) Any use permitted in the R1 and R2 districts;

  • (b) Multiple family dwellings, as defined in this title;

  • (c) One family row dwellings, as defined in this title;

(d) Supportive housing in compliance with Government Code Sections 65650 - 65656, shall be considered a use by-right use. "Use by right" shall have the same meaning as defined in Government Code Section 65583.2(i) . Supportive housing shall also be in compliance with Section 27.94.020 By-Right Residential Use Requirements and subject only to those objective development standards and policies that apply to other multifamily development within the same zone.

(e) Accessory uses which are necessary to the above-mentioned buildings and uses.

27.22.020 SPECIAL USES.

Unless otherwise provided, the following uses may be allowed if a special use permit is approved:

  • (a) Any special use permitted in the R1 and R2 districts;

  • (b) Bed and breakfast inns;

(c) Boarding and lodging houses with a five (5) resident limitation;

(d) Residential care facility (excluding group homes) with seven (7) or more residents in addition to the caregiver. Certain licensed care facilities shall be subject to separation requirements pursuant to Health and Safety Code Section 1267.9 ;

  • (e) Day care centers.

27.22.030 OFF-STREET PARKING.

Off-street parking facilities shall be provided as required in the off-street parking code (Chapter 27.64).

27.22.040 MINIMUM DEVELOPMENT STANDARDS.

(a) Every dwelling hereafter erected or structurally altered to create one or more additional dwelling units shall be on a parcel having the following minimum development standards:

Minimum Parcel Area (Square Feet) Minimum Parcel Width (Lineal Feet) Minimum Parcel Area/D.U.
(Square Feet)
4,000* 40* 2,200*
5,000 50 2,500
8,000 65 2,000
10,000 80 1,500
15,000 100 1,250
*** These standards are permitted only if a parcel is lying northeasterly of El Camino Real and wa** s recorded prior to March 3, 1947.

(b) A larger minimum parcel for special uses shall be required by the Planning Commission upon a finding that the minimum parcel area does not adequately accommodate the proposed special use.

(Ord. No. 1991-18 § 5; Ord. No. 1985-3 § 2; Ord. No. 1979-1 § 6; prior code § 146.04(D).)

Cross References

Section 27.30.010(p) Section 27.44.020(g)

27.22.050 MAXIMUM FLOOR AREA RATIO.

The floor area ratio of buildings and structures on a parcel in this district shall not exceed 0.85, except that the zoning administrator may grant permission to exceed the above maximum floor area ratio, using the procedures outlined for special uses as provided in this title, if the additional floor area will:

(1) Not exceed a floor area ratio of 1.0;

(2)(A) Be equal to the additional floor area that is required to cover any parking space that is not otherwise required to be covered by provisions of this title, or

(B) Is necessary to cover any required turnaround area for required parking, and

(C) Increase the livability by providing more usable yard area than could be provided without the permitted increase in floor area.

27.22.055 BUILDING HEIGHT.

Building height shall not exceed the standards set forth on the Building Height Plan of the General Plan.

27.22.060 YARD AREAS GENERALLY.

Buildings shall not be erected or enlarged unless the yard areas in the following Sections (27.22.070 through 27.22.090) are provided and maintained in connection with such building, structure or enlargement. Notwithstanding the requirements for front, side, and rear yards (27.22.070 through 27.22.090) and at the City's option, required yards may be combined in various ways to maximize certain locational factors. Such combinations shall be considered by the City as a part of planning application review.

27.22.070 FRONT YARDS.

(a) A front yard of not less than fifteen feet (15') shall be provided. For buildings exceeding three (3) stories in height, the minimum front yard shall be one-half (1/2) the height of the building, unless a smaller setback is allowed in the granting of a special use permit.

On a parcel being developed for multiple-family use, if the front of the parcel abuts an R1 or R2 zoned parcel, the front setback measured from the property line shall be equal to the building height, or fifteen feet (15'), whichever is greater.

(b) Garages in Embankments. The same regulations shall apply as in the R1 districts.

  • (c) Private Roads. The same regulations shall apply as in the R1 districts.

(d) Subdivision Maps. The same regulations shall apply as in the R1 districts.

(Ord. No. 1985-3 § 2; Ord. No. 1979-26 § 5; Ord. No. 1979-1 § 8; prior code § 146.04(F)(1-4).)

Cross References

Section 27.22.060

27.22.080 SIDE YARDS.

(a) For one family detached dwellings, the same regulations shall apply as in the R1-B district.

(b) For two family dwellings, the same regulations shall apply as in the R2 district.

(c) For one and two story multiple family dwellings there shall be provided and maintained a side yard of not less than six feet (6') on each side of the principal building(s). For multiple family dwelling structures of more than two stories in height, the side yard adjacent thereto shall be onehalf (1/2) the height of the building to a maximum of twenty-five feet (25') unless a greater dimension is required as a condition of approval for a special use permit.

(d) For one and two story multiple family dwellings on corner parcels, there shall be maintained a minimum side yard of not less than seven and one-half feet (7-1/2') on the side adjacent to the street which intersects the street upon which the building maintains frontage. In the case of a reversed corner parcel, there shall be maintained a setback from the side of not less than fifty percent (50%) of the front yard required on the parcels in the rear of such corner parcels but such setback need not exceed ten feet (10'). Accessory buildings on said reversed corner parcel shall not project beyond the front yard requirement on the adjacent parcel to the rear; nor be located nearer than six feet (6') to the side parcel line of said adjacent parcels. For multiple family dwelling structures of more than two (2) stories in height on corner parcels, the minimum required side yard shall be one-half (1/2) the height of the building to a maximum of twenty-five feet (25') unless a greater dimension is required as a condition of approval for special use permits.

(e) On a parcel being developed for multiple-family use, if the side of the parcel abuts an R1 or R2 zoned parcel, the side yard setback on that side measured from the property line shall be equal to one-half (1/2) the height of the building, or fifteen feet (15'), whichever is greater.

(f) On a parcel improved pursuant to a special use permit with a nonresidential building, exclusive of residential accessory buildings, there shall be a side yard of not less than ten feet (10') on each side of the principal structure. For those nonresidential structures of more than two stories in height, there shall be provided and maintained a side yard setback equal to one-half

(1/2) the height of the building, or fifteen feet (15'), whichever is greater. Additional side yard setback may be required as part of the conditions of a special use permit. When a special use is proposed for a parcel which abuts an R1 or R2 zoned parcel, the provisions of subsection (e) shall apply.

(Ord. No. 1985-3 § 2; Ord. No. 1982-22 § 27; Ord. No. 1979-26 § 6; Ord. No. 1979-1 § 9; prior code § 146.04(F)(5).)

Cross References

Section 27.22.097

27.22.090 REAR YARDS.

On a parcel upon which a building is constructed there shall be a rear yard setback of not less than fifteen feet (15'). For buildings more than three stories in height, the minimum rear yard shall be one-half (1/2) the height of the building to a maximum of twenty-five feet (25') unless a greater dimension is required as a condition of approval for special use permits. When a parcel zoned for multiple family use abuts an R1 or R2 zoned parcel, the rear yard setback measured from the property line shall be equal to the building height. All required rear yards shall be unobstructed from ground level to the sky, except as otherwise provided in this title.

(Ord. No. 1985-3 § 2; Ord. No. 1979-26 § 7; Ord. No. 1979-1 § 10; prior code § 146.04(F)(6).)

Cross References

Section 27.22.060

Section 27.22.097

27.22.095 SPECIAL YARDS.

Properties from Ninth Avenue south to the City limits which have frontage on El Camino Real shall provide the following yards:

(a) A minimum of ten (10) feet along El Camino Real frontage, where property is developed with buildings over two stories in height;

(b) One-half (1/2) the height of any building, where the property is adjacent to residential districts.

27.22.097 BUILDING HEIGHT AND SPECIAL YARD REQUIREMENTS—DOWNTOWN SPECIFIC PLAN GATEWAY AREA.

Properties within the Gateway area as defined in the Downtown Specific Plan shall conform with the following building height and yard requirements: interior side yard and rear yard setbacks shall conform with sections 27.22.080 and 27.22.090:

Property
Street
Frontage
Yard Requirement Building Height Standard Additional Yard Requirement
Third
Avenue
Buildings shall be set back a minimum
of 20 feet from the Third Avenue
property line for at least 60% of the
building frontage.
No additional building height
standard beyond conformance with
maximum building height as
designated in the Downtown
Specific Plan.
None.
Fourth
Avenue
Buildings shall be set back a minimum
of 15 feet to a maximum of 20 feet
from the Fourth Avenue property line
for at least 60% of the building
frontage.
Building height at the setback line
shall be a minimum of 20 feet to a
maximum of 30 feet.
Portions of the building over 30 feet in height
shall be setback a minimum of 8 feet behind
the front building facade as established in
conformance with the "yard requirement"
column.
Other
Gateway
Streets
Buildings shall be set back a minimum
of 15 feet to a maximum of 20 feet
from the street property line for at least
60% of the building frontage.
Building height at the setback line
shall be a maximum of 25 feet.
Portions of the building over 25 feet in height
shall be setback a minimum of 8 feet behind
the front building facade as established in
the "yard requirement" column.

27.22.098 CONFORMANCE WITH GATEWAY DESIGN STANDARDS.

All building additions and new buildings within the Gateway area as defined in the Downtown Specific Plan shall conform with the Gateway Design Guidelines.

27.22.100 OPEN SPACE REQUIREMENTS.

(a) The open space requirements of this district are in addition to any open space requirements resulting from the approval and filing of a subdivision map, or any open space requirements imposed upon a planned development in accord with the general plan. Open space required by this section is intended to be for the use and enjoyment of the residents of the multiple-family project.

(b) Not less than two hundred (200) square feet per bedroom of open parcel area, exclusive of any required off-street parking areas or driveways, shall be provided for the first bedroom in each dwelling unit and at least one hundred (100) square feet per bedroom of open parcel area, exclusive of any required off-street parking areas or driveways, shall be provided for each bedroom after the first bedroom in each dwelling unit.

(c) The required open parcel area for each ground floor dwelling unit shall be continuous thereto, and shall have a minimum dimension of not less than ten feet (10') in any direction. Such open parcel area may include the required minimum yard areas set forth in this chapter. Where provision of contiguous open space for ground floor units conflicts with required fire department access, a redistribution of open space may be required, subject to the approval of the fire chief.

(d) Open roof decks, balconies, lanais or other open structural areas made a part of the building and improved for outdoor living, may be used to satisfy the open parcel area requirements for each dwelling unit above the ground floor provided that the open roof deck, balcony, lanai, or other open structural area contains a usable area of not less than one hundred (100) square feet and is not less than six feet (6') in any dimension. Required open space for units above the ground floor may be combined for several units and located on the ground.

Whether or not required open space is combined, it may be located in whole or in part on the ground, provided that the minimum dimension is ten feet (10') in any direction. Such open space need not be contiguous to the building.

(e) The proposed improvement of all required open parcel area (garden patios) or roof decks, balconies, lanais or other structural areas intended for outdoor living shall be designated on plans submitted with planning applications, and upon the approval of such plans shall be considered a required part of the site and structural improvements.

27.22.110 DWELLING STANDARDS.

Every multiple family building hereinafter erected or established in a multiple family district, shall provide a minimum floor area for each dwelling unit with or without a kitchen in compliance with the following:

Unit Type Square Feet
(a) Bachelor or studio-type dwelling units
(1) Without kitchens 350
(2) With kitchens 350
Unit Type Square Feet
(b) One-bedroom dwelling units
(1) Without kitchens 500
(2) With kitchens 540
(c) Two-bedroom dwelling units
(1) Without kitchens 600
(2) With kitchens 750
(d) Three-bedroom dwelling units 960

The floor area shall be measured from the center of the walls enclosing each dwelling unit, and may include all closet space and storage area contained within the dwelling unit; but shall not include outside patios, balconies, or terraces, or utility rooms used jointly by the occupants.

(Ord. No. 1985-3 § 2; prior code § 146.04(H).)

Cross References Section 27.28.034 Section 27.28.064 Section 27.28.094

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Contents — San Mateo Zoning Code
San Mateo Zoning Code
  1. Title 27 — ZONING
    Overview
    1. Chapter 27.02 — GENERAL PROVISIONS
    2. Chapter 27.04 — DEFINITIONS
    3. Chapter 27.06 — ADMINISTRATION
    4. Chapter 27.08 — RULES OF PROCEDURE
    5. Chapter 27.10 — REVIEW PROCEDURE
    6. Chapter 27.12 — FEES
    7. Chapter 27.13 — TRANSPORTATION IMPROVEMENT FEE
    8. Chapter 27.14 — REDEVELOPMENT
    9. Chapter 27.15 — DENSITY BONUS
    10. Chapter 27.16 — RESIDENCE DISTRICTS
    11. Chapter 27.18 — R1 DISTRICTS
    12. Chapter 27.19 — ACCESSORY DWELLING UNITS AND JUNIOR ACCESSORY …
    13. Chapter 27.21 — TWO-UNIT
    14. Chapter 27.24 — R4 DISTRICT—MULTIPLE FAMILY DWELLINGS (HIGH DE…
    15. Chapter 27.26 — R5 DISTRICT—MULTIPLE FAMILY DWELLINGS (HIGH DE…
    16. Chapter 27.27 — RESIDENTIAL
    17. Chapter 27.28 — DOWNTOWN
    18. Chapter 27.29 — RESIDENTIAL OVERLAY DISTRICT—MIXED USE
    19. Chapter 27.30 — C1 DISTRICTS— NEIGHBORHOOD COMMERCIAL
    20. Chapter 27.32 — C2 DISTRICTS—
    21. Chapter 27.34 — C3 DISTRICTS—
    22. Chapter 27.36 — C4 DISTRICTS
    23. Chapter 27.38 — CBD DISTRICTS— CENTRAL BUSINESS DISTRICT
    24. Chapter 27.39 — CBD SUPPORT DISTRICT— CENTRAL BUSINESS DISTRIC…
    25. Chapter 27.40 — BUILDING HEIGHT AND BULK
    26. Chapter 27.44 — E1 DISTRICTS—EXECUTIVE PARK
    27. Chapter 27.48 — E2 DISTRICTS —EXECUTIVE OFFICES
    28. Chapter 27.54 — MANUFACTURING DISTRICTS
    29. Chapter 27.56 — M1 DISTRICTS
    30. Chapter 27.59 — S DISTRICTS
    31. Chapter 27.60 — SPECIAL DISTRICTS
    32. Chapter 27.61 — SC DISTRICTS—SENIOR CITIZEN OVERLAY DISTRICT—S…
    33. Chapter 27.62 — PLANNED DEVELOPMENTS —SPECIAL USE PERMITS
    34. Chapter 27.63 — ADULT ENTERTAINMENT BUSINESSES
    35. Chapter 27.64 — OFF-STREET PARKING AND LOADING
    36. Chapter 27.65 — AMUSEMENT ARCADES AND MACHINES
    37. Chapter 27.66 — HISTORIC PRESERVATION
    38. Chapter 27.67 — OPEN AIR VENDORS
    39. Chapter 27.68 — MAINTENANCE OF PROJECT SITE
    40. Chapter 27.69 — RECYCLING FACILITIES
    41. Chapter 27.70 — ACCESSORY BUILDINGS AND STRUCTURES IN REQUIRED…
    42. Chapter 27.72 — NONCONFORMING BUILDINGS AND USES
    43. Chapter 27.73 — TC DISTRICT—
    44. Chapter 27.74 — SPECIAL USE PERMITS
    45. Chapter 27.75 — MIXED USE CONVENIENCE MARKET/AUTOMOBILE SERVIC…
    46. Chapter 27.76 — PERFORMANCE STANDARDS
    47. Chapter 27.77 — DESIGN REVIEW STANDARDS FOR SERVICE STATIONS
    48. Chapter 27.78 — VARIANCES
    49. Chapter 27.79 — REASONABLE
    50. Chapter 27.80 — AMENDMENTS
    51. Chapter 27.82 — MAPS—BOUNDARY LINES
    52. Chapter 27.83 — SLOPE AND HILLSIDE DEVELOPMENT STANDARDS
    53. Chapter 27.84 — FENCES, TREES AND HEDGES
    54. Chapter 27.85 — DAY CARE CENTERS
    55. Chapter 27.86 — RECYCLING COLLECTION AREAS
    56. Chapter 27.87 — OUTDOOR RESTAURANT SEATING AND MERCHANDISE DIS…
    57. Chapter 27.88 — BAY MEADOWS SPECIFIC PLAN
    58. Chapter 27.90 — TOD DISTRICT— TRANSIT ORIENTED DEVELOPMENT
    59. Chapter 27.92 — HILLSDALE STATION AREA PLAN
    60. Chapter 27.94 — HOUSING

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