San Carlos Zoning, Planning & Building Codes

Last reviewed: July 3, 2026

Overview

San Carlos’s land-use rules are codified in the San Carlos Zoning Ordinance (commonly called Title 18), which implements the General Plan and organizes rules for uses, dimensional standards, procedures and permits. The ordinance is organized into five Articles that separate base and overlay districts, citywide standards, administration and definitions so you can find rules by topic or by district (§ 18.01.030) . This page highlights where the major rules live, the district families that shape allowed uses and form, the typical development standards you’ll encounter, how overlays and specific plans modify the base code, and the typical permit paths — all grounded in the local code.

(First-time readers: this is about the City Zoning rules specifically — see the city’s main zoning portal for maps and staff contacts at San Carlos Zoning.)

How San Carlos’s code is organized

• The zoning ordinance is arranged into five Articles: Article I (general provisions), Article II (base and overlay districts), Article III (regulations that apply to some or all districts), Article IV (administration and permits), and Article V (definitions/use classifications) (§ 18.01.030) .
• Applicability and the rule that the code applies to all property within city limits are in § 18.01.040 (§ 18.01.040) .
• Because the ordinance separates content by function, the practical navigation approach is:
  • Look up the base district chapter for allowed uses and district-specific standards (Article II chapters such as Chapters 18.04 and 18.05) (§ 18.01.030) .
  • Check Article III for citywide site rules (setbacks, height exceptions, projections) (§ 18.15.010) .
  • Use Article IV to understand who decides (Director, Zoning Administrator, Planning and Transportation Commission, City Council) and the appeal ladder (§ 18.26.070) .
• Practical tip: start with the base district chapter that matches your parcel, then confirm overlay or specific-plan chapters that may supersede the base rules (§ 18.14.1 and overlay chapters) .

Zoning district families

San Carlos defines a set of base districts and overlay districts in Article II. Key families and where to read them:

• Residential: single‑family and multi‑family districts are in Chapter 18.04. The code explicitly identifies RS-3 and RS-6 single‑family districts and RM multifamily districts, with development type rules and objective design standards located in §§ 18.04.010–18.04.100 (§ 18.04.010) .
  • Example: RS-3 is intended for up to 3 du/acre; RS-6 for up to 6 du/acre (purpose statements) (§ 18.04.010) .
• Mixed‑Use (MU): several targeted MU districts are defined in Chapter 18.05 (e.g., MU-DC-100, MU-D-100, MU-D-120, MU-SA-50, MU-SC-120, MU-NB-120, MU-SB-100, MU-N-40) with stated unit-per‑acre intensities and building-form standards (§ 18.05.010 and tables in § 18.05.030) . These MU districts call for pedestrian/transit orientation and include height and stepback tables for each MU subtype (§ 18.05.030) .
• Public & Semi‑public: Public districts (P, PK, OS) are in Chapter 18.08, with their own development standard table (Table 18.08.030) for setbacks, height and lot coverage (§ 18.08.030) .
• Planned Development (PD): the PD mechanism allows site‑specific standards and is used to adopt specific plans; rules for PD district minimum area, open space and required PD plan contents are in Chapter 18.10 (§ 18.10.010–.040) .
• Overlay Districts: overlays (such as the Gateway (G) and Neighborhood Hub (NH) overlays and the Hillside Overlay) layer additional standards or design criteria on top of base zoning; see Chapters 18.11, 18.13, and 18.12 for purpose, applicability and development rules (§ 18.11.010; § 18.13.010; § 18.12.070) .
• How to find a parcel’s zoning: consult the official zoning map and the “Districts established” rules in § 18.01.070 (§ 18.01.070) .

(For a quick, clickable orientation to these topic pages see San Carlos Land Use, and to the mixed-use and development rules see San Carlos Development Standards.)

Citywide development standards (how form is controlled)

Where the code controls form and the most common numbers you’ll run into:

• Organization: citywide site and dimensional rules that apply across districts are in Chapter 18.15 (General Site Regulations) — items such as height measurement, projections into yards, fences, underground utilities live here (§ 18.15.010) .
• Residential district standards and objective design standards are in § 18.04.030–18.04.040 (development standards—RS districts and objective design standards) (§ 18.04.030) .
• Typical numeric examples you will see in district‑level tables:
  • Small‑lot single‑unit standards (Table 18.04.100‑G) include a maximum FAR of 0.45, maximum lot coverage 35%, and a maximum height of 28 ft for the small‑lot product type (Table 18.04.100‑G) — see Table 18.04.100‑G and its heading in § 18.04.100 (§ 18.04.100) .
  • Mixed‑use districts contain district‑specific height caps (for example MU-DC-100 up to 50 ft, MU‑D‑120 up to 75 ft; consult the MU height table in § 18.05.030) (§ 18.05.030) .
• Parking: base parking and loading standards are organized under the parking chapter and district tables (see Chapter 18.20 and district tables; SB 9 / urban infill rules also set parking requirements for those units) — example: SB 9 urban infill units require one uncovered parking space per new unit except where transit distance or car‑share conditions apply (§ 18.23.310) (see San Carlos Parking for the topic landing page).
• Design and objective standards: many MU and RS rules include objective design standards that trigger compliance review or design review when changes are proposed (§ 18.29.020) (see San Carlos Design Review).
• Performance standards (noise, odor, hazardous materials and airport ALUCP consistency) that apply to all uses are in Chapter 18.21 (§ 18.21.010–.150) .

(If you need sign rules, landscaping rules, nonconforming uses or variance pathways, see the matching topic pages: San Carlos Signage, San Carlos Landscaping and Screening, San Carlos Nonconforming Uses, and San Carlos Variances and Exceptions.)

Specific plans & overlays

• Downtown Specific Plan: adopted as a local specific-plan chapter 18.14.1, the Downtown Specific Plan establishes a separate regulatory framework for downtown land use, urban design, parking/transportation and administration; permits in the Downtown must be consistent with the Specific Plan, and where the Specific Plan conflicts with the municipal code the Specific Plan controls (§ 18.14.1.010–.040) (see the Downtown Specific Plan chapter for details).
• Planned Development and Specific Plans: the PD district can be used to implement specific plans; PD plans set site‑specific standards and are adopted by City Council following Planning & Transportation Commission review (§ 18.10.010–.040) .
• Overlays: Gateway (G), Neighborhood Hub (NH) and the Hillside overlay add additional design criteria or limits and are found in Chapters 18.11, 18.13, and 18.12 respectively; overlay chapters specify applicability, design requirements and any modified development standards (§ 18.11.010; § 18.13.010; § 18.12.070) (see San Carlos Overlay Districts for navigation).

Building permits & review — the practical permit path

• Ministerial vs. discretionary: the code distinguishes ministerial (Type 1) actions such as zoning clearances from discretionary (Type 2/3) actions such as conditional use permits, variances and rezonings. The summary of review authorities and appeal ladder is in Table 18.26.070 (§ 18.26.070) .
• Zoning clearance (ministerial): a zoning clearance verifies compliance with the code before the city issues a building permit or business license; the Director issues the clearance if the project conforms to the applicable development and use standards (§ 18.28.030) (see San Carlos Zoning for the landing page).
• Discretionary entitlements:
  • Use permits / conditional use permits: procedures and required findings are in Chapter 18.30; the decision‑maker and appeals path vary by permit type (§ 18.30.070–.080) .
  • Design review / compliance review: required for most exterior changes and new construction under Chapter 18.29; the chapter explains assignment of review responsibilities, criteria and findings (§ 18.29.010–.060) (see San Carlos Design Review).
  • Variances and waivers: Chapters 18.32 (variances) and 18.33 (waivers) provide relief mechanisms when strict application of the code would be unfair — both have required findings and appeal rules (§ 18.32.010; § 18.33.010) .
• SB 9 / urban infill splits: Chapter 18.23.310 implements the city’s objective standards and ministerial review process for Senate Bill 9 subdivisions and urban infill units on qualifying single‑family lots (e.g., eligibility limits, a ministerial approval path and objective standards for height, setbacks, parking) — see § 18.23.310 for the full set of standards and the rule that lot splits and related development are ministerially approved without discretionary hearings (§ 18.23.310) .
• Plan approvals and PD rezones: PD rezoning and PD plan approvals go to the Planning & Transportation Commission and City Council and require specific findings that include consistency with the General Plan and demonstration that the PD is superior to base‑district development (§ 18.36.040–.050) .
• Building code & inspections: building‑permit technical review is governed by the adopted California Building Standards Code (Title 24), enforced alongside local zoning clearances and building permits (refer to the City’s Building Division and the California Building Standards Code) (verify locally with the Building Division; see San Carlos ADUs and California Building Standards Code).

State housing law in San Carlos — how statewide rules interact locally

San Carlos’s code implements and references multiple California housing laws and exemptions; here are the highest‑impact interactions and where they are found in the local code.

• Accessory dwelling units (ADUs and JADUs): the municipal ADU rules are in § 18.23.210 and include:
  • Objective ADU development standards (setbacks, height, size rules and parking rules) and sections that implement statewide exemptions (e.g., up to 800 sq ft exemptions and four‑foot side/rear setbacks in some statewide‑exempt situations) (§ 18.23.210 and Table 18.23.210(E)(4)) .
  • Parking: generally one parking space per ADU unless the statewide exceptions apply (e.g., proximity to transit, car‑share, conversion of a garage) (§ 18.23.210(G)) .
  • Height/size: attached ADUs capped as specified (attached up to 25 ft per local table) and detached ADU heights follow local adjustments consistent with state limits; conversions of existing accessory structures may have different rules and exemptions (§ 18.23.210 and Table 18.23.210) .
  • The code explicitly references conformity with state ADU statutes (statewide exemptions and permitting timeframes) — see local ADU chapter for timing and fee rules; for statewide provisions refer to California ADU law and the California Building Standards Code (see San Carlos ADUs and California ADU law).
• SB 9 / urban infill (two‑unit splits and duplex conversions): implemented in § 18.23.310 as an objective, ministerial process for qualifying RS‑3/RS‑6 parcels. Key points: eligibility limits, objective standards for setbacks and heights (e.g., maximum height 16 ft for many urban infill units, with some exceptions), ministerial approval without discretionary public hearings, and specific requirements for parking and deed restrictions/affidavits where required (§ 18.23.310) .
• Density bonus and affordable housing incentives: the City dedicates chapters to affordable housing programs and incentives (for example Chapter 18.16 and 18.17 dealing with density bonus and incentives), and PD‑level residential densities must account for density‑bonus allowances when applicable (§ 18.36.040 and references to Chapters 18.16–18.17) .
• Rent control and tenant protections: the municipal zoning code focuses on land use and does not itself establish a citywide rent control regime; search the city municipal code or contact the City Clerk for ordinances outside Title 18 (Zoning) that regulate rents — the zoning title does, however, include provisions that affect conversion/demolition of occupied housing (e.g., SB 9 and urban infill eligibility exceptions for certain tenant‑occupied or subject‑to‑covenant properties) (§ 18.23.310 eligibility exclusions) .

Practical orientation — “If I’m starting a project, do this”

1. Identify the parcel’s base zone and overlays on the official zoning map and read the base district chapter (e.g., § 18.04 for residential, § 18.05 for MU) (§ 18.01.070; § 18.04.010; § 18.05.010) .
2. Check for applicable overlays or a Downtown Specific Plan (e.g., § 18.11, § 18.12, § 18.14.1) — those chapters can override base rules (§ 18.11.010; § 18.12.070; § 18.14.1.040) .
3. For small projects: determine whether your work is ministerial (zoning clearance § 18.28.030) or requires design/compliance review (§ 18.29) or a use permit (§ 18.30) and follow the applicable Chapter 18.27 application procedures (§ 18.28.030; § 18.29.020; § 18.30.070; § 18.27.020) .
4. If proposing ADUs or SB9 units, consult § 18.23.210 (ADU rules) and § 18.23.310 (SB 9 urban infill) early — both chapters contain objective standards and ministerial pathways where the code allows (§ 18.23.210; § 18.23.310) .
5. Expect to coordinate with building and fire officials for technical compliance (California Building Standards Code / Title 24), and be prepared for impact fees or capacity charges where state law allows (see § 18.23.210(H) on ADU fees and § 18.23.310(D) on development fees) (§ 18.23.210(H); § 18.23.310(D)) .

Source References

• San Carlos Zoning Ordinance — Structure, introductory provisions (§ 18.01.030; § 18.01.040)
• Chapter 18.04 Residential Districts — RS and RM district purposes and development types (§ 18.04.010–.030)
• Chapter 18.05 Mixed‑Use Districts — MU district types, densities and height tables (§ 18.05.010; § 18.05.030)
• Chapter 18.08 Public & Semi‑Public development standards (Table 18.08.030) (§ 18.08.030)
• Chapter 18.10 Planned Development District (PD) — PD purposes and PD plan requirements (§ 18.10.010–.040)
• Chapter 18.11 Gateway Overlay District — purpose and applicability (§ 18.11.010–.030)
• Chapter 18.12 Hillside Overlay / landscaping provisions (§ 18.12.070)
• Chapter 18.14.1 Downtown Specific Plan — applicability and consistency rules (§ 18.14.1.010–.050)
• Chapter 18.15 General Site Regulations — height, projections, and sitewide rules (§ 18.15.010)
• Chapter 18.21 Performance Standards (noise, ALUCP consistency) (§ 18.21.010–.150)
• Chapter 18.23 — Accessory Dwelling Units / Junior ADUs (§ 18.23.210) and Urban Infill / SB 9 units (§ 18.23.310)
• Chapter 18.26 Planning Authorities and Table 18.26.070 review authority (§ 18.26.010–.020; § 18.26.070)
• Chapter 18.27 Common Procedures (applications, notice, appeals) (§ 18.27.020; § 18.27.150)
• Chapter 18.28 Zoning Clearance — ministerial review prior to building permits (§ 18.28.010–.030)
• Chapter 18.29 Design Review and Objective Design Standards Compliance Review (§ 18.29.010–.060)
• Chapter 18.30 Use Permits — findings, conditions and appeals (§ 18.30.070–.080)