Zoning › California › San Mateo County › Foster City

Foster City, CA Zoning

Euclidean-zoning. 13 districts · 5 overlays · 6 applicable state preemptions.

Overview

Code type
euclidean
Naming convention
letter-code

Foster City uses letter-code district designations (R-1, R-2, R-T, R-3, R-4, C-O, C-1, C-2, C-M, C-A, M-1, PF, OSC). Numbers in residential codes are sequential index, not dimensional. PD is a combining district overlaid on base zones — not a dominant planning mechanism, so euclidean classification is correct. The planned community was established in 1971 on engineered fill with an interior lagoon system; as a result, OSC/W (aquatic combining) zones are prominent on the zoning map.

Worth knowing
  • Foster City is a planned community on engineered bay fill (incorporated 1971), giving it an unusually high proportion of OSC and OSC/W (aquatic combining) zones reflecting the interior lagoon system and bay margins. (§17.40)
  • R-T (Townhouse) and C-M (Commercial Mix) districts MUST be used only in conjunction with the PD combining district — they have no standalone dimensional standards; all regulations are set by use permit. (§17.16.040, §17.28.020)
  • C-A (Commercial Automobile) district was created specifically to protect the three remaining gasoline/auto repair service stations in the city; the district restricts conversion of any service bays and requires a use permit for every allowed use. (§17.29.010)

+ 2 more in Quirks & notes

Districts

com 4res_mf 3res_sf 2spec 2off 1ind 1
CodeNameCategory Min lotHeight CoverageFAR Du/acParking Setbacks F/S/R
R-1Single-Family Residence Districtres_sf5,000 sf[4]25 ft[5]50[6]—8[7]—[8]20[1] / 5[2] / 20[3]
R-2Two-Family Residence Districtres_sf5,000 sf[12]25 ft[13]50[14]—13[15]—[16]20[9] / 5[10] / 20[11]
R-TTownhouse Residence Districtres_mf—[20]38 ft[21]50[22]—15[23]—[24]5[17] / 0[18] / 0[19]
R-3Medium Density Multiple-Family Residence Districtres_mf15,000 sf[28]38 ft[29]50[30]—35[31]—[32]10[25] / 10[26] / 10[27]
R-4High Density Multiple-Family Residence Districtres_mf15,000 sf[36]55 ft[37]50[38]—35[39]—[40]10[33] / 5[34] / 10[35]
C-OCommercial Office Districtoff10,000 sf[44]36 ft[45]35[46]—[47]——[48]20[41] / 10[42] / 10[43]
C-1Neighborhood Business Districtcom5,000 sf[52]20 ft[53]25[54]———[55]0[49] / 0[50] / 0[51]
C-2General Business Districtcom40,000 sf[59]—[60]——60[61]—[62]0[56] / 0[57] / 0[58]
C-MCommercial Mix Districtcom—[66]—[67]————[68]—[63] / —[64] / —[65]
C-ACommercial Automobile Repair and Service Districtcom—[72]—[73]————[74]—[69] / —[70] / —[71]
M-1Light Industrial Districtind20,000 sf[78]—[79]————[80]25[75] / 0[76] / 0[77]
PFPublic Facilities Districtspec—[84]—[85]————[86]—[81] / —[82] / —[83]
OSCOpen Space and Conservation Districtspec—[90]—[91]————[92]—[87] / —[88] / —[89]

Confidence: confirmed partial under review not found

Overlays

PD
Planned Development Combining District
PD
§17.36

Applied as combining district upon property owner application or city council/planning commission initiative; may be attached to any base zone on the zoning map per Ch. 17.74 amendment procedure.

usesAll uses must be specified in the PD zoning ordinance; PD may cover SF residential, MF housing, shopping centers, professional/administrative areas, commercial service centers, industrial parks, or combinations.
development_standardsStandards set by the PD ordinance; unless otherwise specified, general zoning provisions apply. CUP or use permit required for development within the PD zone.
flexibilityPD is designed to allow flexibility of design consistent with the General Plan objectives.
W
Aquatic Development Combining District
ENV
§17.40

Applied to OSC-zoned land overlying waters of San Francisco Bay, Belmont Cove, Marina Lagoon, and the interior lagoon system of Foster City.

permitted_usesAquatic sports and boating (with restrictions); city-sponsored aquatic events by right.
conditional_usesPrivately-sponsored aquatic events; structures supporting permitted W uses; shoreline modification, fill, or dredging — all require use permit.
area_iii_restrictionInterior lagoon system from Shell Boulevard Bridge to 19th Avenue Freeway: only sailboats ≤20 ft mast height and small unpowered boats permitted; no internal combustion engines.
consistencyAll W district changes must conform to the General Plan.
SHO
Senior Housing Overlay District
AH
§17.37

Floating district; applied only in conjunction with PD combining district upon developer application. Not mapped to a fixed location until application and approval.

target_populationSenior citizens age 62+, with annual income qualifying as very low, low, or moderate income under state law definitions.
density_incentivesProvides density incentives above base zone to facilitate affordable senior rental housing; specific density set per development agreement.
parking_reductionProjects exempt from §17.62.060(A)(3) and (A)(5) parking requirements for senior-designated units.
development_agreementFormal development agreement required per §17.37.060 as condition of overlay approval.
unit_mixOnly a percentage of total project units (negotiated project-by-project) reserved for senior occupancy.
X
Future Development Combining District
SPEC
§17.38

Applied to land designated for future development not yet planned or programmed; used as a holding zone on the zoning map.

purposeHolds land in a reserve status pending future planning decisions; development not permitted until the X combining district is replaced by a base zone through the Ch. 17.74 amendment process.
FP
Floodplain / FEMA SFHA
FP
§17.32

Foster City sits on engineered bay fill and has FEMA-mapped Special Flood Hazard Areas (SFHAs). Foster City participates in FEMA's NFIP. Floodplain regulations are embedded in development standards for applicable zones rather than a standalone overlay chapter in Title 17.

fema_statusFoster City participates in NFIP (Community ID confirmed through FEMA MSC). Engineered fill creates localized SFHA areas along lagoon margins.
local_freeboardNot captured — Title 17 does not contain a standalone floodplain overlay chapter in the Wayback-accessible sections; floodplain standards are referenced via building code and Public Facilities district provisions.
sfha_noteFederal overlay — federal law preempts local minimums; NFIP compliance required.

State preemptions

ca-density-bonus-lawapplies
Qualifying condition
Statewide mandate — GC §65915 applies to all California cities. Foster City (pop. 34,494, Census 2020) has multifamily and commercial zones (R-3, R-4, C-2) that qualify as density bonus sites. HCD data: Housing Element certified In-compliance, 6th Cycle (reviewed 2024-04-18). City is RHNA-exempt (SB 35 tier=Exempt; above-mod permits 535.3% complete). Density bonus law applies regardless of RHNA status.
Effect
Up to 80% base density bonus for qualifying housing projects with affordable units; parking reductions per §65915(p).
ca-sb9-home-actapplies
Qualifying condition
Foster City has single-family zones (R-1, R-1/PD) subject to SB 9 ministerial lot splits and duplex conversions. City population 34,494 (2020 Census) — no population threshold excludes application. GC §65852.21 applies citywide except on parcels in high fire severity zones, historic districts, or environmental resource protection areas. No historic district overlay found in Title 17.
Effect
Ministerial approval of up to 4 units (via lot split + duplex) on qualifying R-1 parcels; overrides local single-family density limits.
ca-ab2011-affordable-housing-high-roadapplies
Qualifying condition
AB 2011 (GC §65912.100+) applies to commercial zones along commercial corridors meeting the act's labor standards. Foster City has C-2 (General Business) and C-M (Commercial Mix) zones on major corridors (E. Hillsdale Blvd, Foster City Blvd). These commercial zones qualify for ministerial multifamily/mixed-use residential development under AB 2011 if high-road labor standards are met.
Effect
Ministerial by-right approval for qualifying multifamily or mixed-use projects on commercial corridor properties meeting AB 2011 labor standards.
ca-adu-jaduapplies
Qualifying condition
Statewide mandate (GC §65852.2). Foster City has adopted Ch. 17.78 Accessory Dwelling Units (Ord. 669 §2 (Exh. A), 2023) explicitly implementing state ADU/JADU law. Applies in all residential zones (R-1, R-2, R-T, R-3, R-4) and PD combining where residential uses are permitted.
Effect
Ministerial approval of at least one ADU up to 1,200 sf and one JADU up to 500 sf on qualifying residential parcels; overrides local restrictions.
ca-sb4-yigby-faith-iheapplies
Qualifying condition
SB 4 (GC §65600) applies statewide to faith institutions and independent higher education campuses regardless of current zoning. Foster City has a Community Facilities (PF) zone and religious institutions exist within the city. SB 4 enables ministerial approval of housing on qualifying faith/IHE sites in all zones.
Effect
Ministerial approval of 100% affordable housing projects on faith institution and independent higher education parcels, overriding local zoning.
ca-ab1287-density-bonus-stackingapplies
Qualifying condition
AB 1287 (amending GC §65915) allows stacking of density bonus from two affordability tiers to achieve up to 100% bonus. Statewide mandate. Foster City has R-3, R-4, and C-2 zones where multi-family development qualifies for density bonus; AB 1287 stacking applies citywide.
Effect
Allows combined density bonus up to 100% base units when a project provides both lower-income and moderate-income or very-low-income units.
Non-applicable laws (4)
ca-ab2097-parking-transitdoes_not_apply
Qualifying condition
GC §65863.2 eliminates parking minimums within 0.5 miles of a qualifying major transit stop (passenger rail station, rapid transit corridor, or high-frequency bus stop intersection). Foster City has no rail station. Caltrain service runs through San Mateo and Hillsdale stations approximately 1.3–1.9 miles from Foster City's core. Bay Meadows Caltrain station is in San Mateo city limits, not within Foster City. No qualifying transit stop within 0.5 miles of Foster City jurisdiction confirmed.
Effect
Does not apply — parking minimums remain in effect under Ch. 17.62.
ca-sb423-streamlineddoes_not_apply
Qualifying condition
SB 35/423 streamlined ministerial approval applies when a city is not meeting RHNA milestones. HCD data for Foster City (hcd-ca-lookup.json): sb423_tier=Exempt; exempt_flag=Yes; above_mod_pct_complete=535.3%; lower_pct_complete=67.8%; Housing Element compliance_status=In (reviewed 2024-04-18). Exempt cities are not subject to SB 35/423 streamlined approval requirements.
Effect
Does not apply — Foster City is SB 35/423 exempt due to meeting RHNA milestones.
ca-builders-remedydoes_not_apply
Qualifying condition
Builder's Remedy applies only when a city lacks a certified Housing Element. HCD data: Foster City Housing Element compliance_status=In; review_status=In; reviewed_date=2024-04-18; planning_period=6S (6th Cycle San Mateo). Housing Element is certified compliant — Builder's Remedy does not apply.
Effect
Does not apply — Housing Element is HCD-certified.
ca-sb10-local-upzoningdoes_not_apply
Qualifying condition
SB 10 (GC §65913.5) is an optional local upzoning tool — cities may adopt a resolution to allow up to 10 units on transit-adjacent or urban infill parcels by ordinance. Foster City has not adopted an SB 10 resolution as of 2026-06-02. No ordinance or resolution found in Title 17 or on city website.
Effect
Does not apply — no SB 10 resolution adopted.

Adopted building codes

Statewide mandatory minimum

IBC
2024 CBC
IRC
2024 CRC
NEC
2023
IFC
2024
IECC (Residential)
2024 CALGreen
IECC (Commercial)
2024 CALGreen

Click a code label to open its state-by-state adoption atlas.

Amendment history

DateKindCitation
2024amendment effectiveOrd. 674 §2 (Exh. B–G), 2024 — most recent residential district amendment
2023amendment effectiveOrd. 657 §4 (Exh. G–M), 2023 — commercial district amendments

Quirks & notes

  • Foster City is a planned community on engineered bay fill (incorporated 1971), giving it an unusually high proportion of OSC and OSC/W (aquatic combining) zones reflecting the interior lagoon system and bay margins. (§17.40)
  • R-T (Townhouse) and C-M (Commercial Mix) districts MUST be used only in conjunction with the PD combining district — they have no standalone dimensional standards; all regulations are set by use permit. (§17.16.040, §17.28.020)
  • C-A (Commercial Automobile) district was created specifically to protect the three remaining gasoline/auto repair service stations in the city; the district restricts conversion of any service bays and requires a use permit for every allowed use. (§17.29.010)
  • Chapter 17.56 sets minimum dwelling unit floor areas independent of zoning district: detached SF 1,800 sf; townhouse 2BR 1,250–1,350 sf; condos 900 sf min; rental apartments 750 sf min 1BR. These minimums apply city-wide regardless of zone. (§17.56.010)
  • The GIS zoning map (Zoning_Hosted FeatureServer, org CYn8XGt0yVlPlS5X) contains 14,203 parcel-level features with ZONECLASS field. Zoning_SHP (98 polygon features) represents district-level polygons. The provided Belmont endpoint was rejected — both Zoning services are Foster City origin (org CYn8XGt0yVlPlS5X, City of Foster City ArcGIS portal).

Formulas

Definitions

height
Vertical distance from average contact ground level to highest point of coping (flat roof), deck line (mansard), or average height of highest gable (pitch/hip roof). §17.04.260
density
Dwelling units per acre of net parcel area.
setback
Minimum horizontal distance required between building face and relative property line. §17.04.490
lot_coverage
Maximum buildable lot footprint as percentage of total lot area.
far
Total gross building square footage divided by net parcel area.

Massing explorer

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District Category Height FAR Coverage Setbacks Parking Density Min lot Overlays

Sources & references

Primary source
https://www.codepublishing.com/CA/FosterCity/
retrieved 2026-06-02
Citations
  1. [1] §17.12.040
  2. [2] §17.12.040
  3. [3] §17.12.040
  4. [4] §17.12.040
  5. [5] §17.12.040
  6. [6] §17.12.040
  7. [7] §17.12.040
  8. [8] §17.62
  9. [9] §17.14.040
  10. [10] §17.14.040
  11. [11] §17.14.040
  12. [12] §17.14.040
  13. [13] §17.14.040
  14. [14] §17.14.040
  15. [15] §17.14.040
  16. [16] §17.62
  17. [17] §17.16.045
  18. [18] §17.16.045
  19. [19] §17.16.045
  20. [20] §17.16.045
  21. [21] §17.16.045
  22. [22] §17.16.045
  23. [23] §17.16.045
  24. [24] §17.62
  25. [25] §17.18.040
  26. [26] §17.18.040
  27. [27] §17.18.040
  28. [28] §17.18.040
  29. [29] §17.18.040
  30. [30] §17.18.040
  31. [31] §17.18.040
  32. [32] §17.62
  33. [33] §17.20.040
  34. [34] §17.20.040
  35. [35] §17.20.040
  36. [36] §17.20.040
  37. [37] §17.20.040
  38. [38] §17.20.040
  39. [39] §17.20.040
  40. [40] §17.62
  41. [41] §17.22.040
  42. [42] §17.22.040
  43. [43] §17.22.040
  44. [44] §17.22.040
  45. [45] §17.22.040
  46. [46] §17.22.040
  47. [47] §17.22.040
  48. [48] §17.62
  49. [49] §17.24.040
  50. [50] §17.24.040
  51. [51] §17.24.040
  52. [52] §17.24.040
  53. [53] §17.24.040
  54. [54] §17.24.040
  55. [55] §17.62
  56. [56] §17.26.040
  57. [57] §17.26.040
  58. [58] §17.26.040
  59. [59] §17.26.040
  60. [60] §17.26.040
  61. [61] §17.26.040
  62. [62] §17.62
  63. [63] §17.28.040
  64. [64] §17.28.040
  65. [65] §17.28.040
  66. [66] §17.28.040
  67. [67] §17.28.040
  68. [68] §17.62
  69. [69] §17.29.050
  70. [70] §17.29.050
  71. [71] §17.29.050
  72. [72] §17.29.050
  73. [73] §17.29.050
  74. [74] §17.62
  75. [75] §17.30.040
  76. [76] §17.30.040
  77. [77] §17.30.040
  78. [78] §17.30.040
  79. [79] §17.30.040
  80. [80] §17.62
  81. [81] §17.32
  82. [82] §17.32
  83. [83] §17.32
  84. [84] §17.32
  85. [85] §17.32
  86. [86] §17.62
  87. [87] §17.34.050
  88. [88] §17.34.050
  89. [89] §17.34.050
  90. [90] §17.34.050
  91. [91] §17.34.050
  92. [92] §17.62

Research status

Publication gates

primary url presentpassedhttps://www.codepublishing.com/CA/FosterCity/ — not an aggregator domain
no aggregator citedpassedscan clean — no zoneomics, steadily, siteplanguide, sitedesignguide, siteplancreator, propwire, zonara, or unzoned references in profile
confidence tags full formpassed14/14 confirmed district standards carry §-citation; 5 overlays confirmed with §-citations; partial fields carry p§ citations with companion reasons
overlays have parameters trigger confidencepassed5 overlays each have non-empty params, trigger, confidence, and ordinance; FP overlay documented as partial with what_is_confirmed/what_is_missing in quirk
preempt section city specificpassed10 preemption laws with city-specific qualifying_condition_checked including numeric HCD data (sb423_tier=Exempt, lower_pct_complete=67.8%, above_mod_pct_complete=535.3%), population (34,494 Census 2020), transit proximity assessment, and ordinance citations

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