Local zoning · Millbrae

Millbrae — Development Standards

Development Standards under the Millbrae local zoning and planning code, with the controlling citations.

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Last reviewed: July 2, 2026

Overview

This page summarizes what the Millbrae municipal zoning ordinance requires for development standards (setbacks, heights, lot coverage, FAR, minimum lot sizes and density) by zoning district. It interprets the code so applicants can see the key decision points and where to look in the ordinance for controlling language. For related rules you’ll commonly need to cross‑check, see the city’s pages on Millbrae Zoning, Millbrae Land Use, Millbrae Parking, Millbrae Design Review, Millbrae Overlay Districts, and Millbrae ADUs. Structural and fire life‑safety rules are governed separately by the California Building Standards Code.

The ordinance language used below is drawn from the City of Millbrae Planning and Zoning code (Title 10). Every numeric requirement below is tied to the specific code section cited.

District-by-district development standards

Notes on reading: each district subsection gives the purpose/typical uses, then the key dimensional standards (lot minimums, lot coverage/FAR, height, setbacks). Citations show the controlling code section (the § number) followed by the file reference to the retrieved ordinance text.

R-1 — Single‑family Residential

  • Purpose & typical uses: The R-1 district preserves detached single‑family character; permitted uses include single‑family dwellings and state‑regulated residential care (§ 10.05.0610) .
  • Key dimensional standards:
    • Minimum lot width: 50 ft interior, 60 ft corner (§ 10.05.0620) .
    • Minimum lot area: 5,000 sq ft (§ 10.05.0620) .
    • Lot coverage: 50% (§ 10.05.0620) .
    • FAR: 55% (floor area ratio defined in Article II; see § 10.05.0620) .
    • Height: maximum 30 ft if the uppermost 5 ft is a roof sloping toward the adjacent street at minimum 3 in/ft; otherwise 25 ft (§ 10.05.0620) .
    • Setbacks (ground floor): Front: 20 ft; interior/exterior side and rear rules vary by configuration and upper floor; see § 10.05.0620 for full table and encroachment rules (eaves, porches) .
  • Practical: FAR includes nuanced counting rules (attics, crawlspaces, porches); read § 10.05.0620 carefully when calculating allowed floor area .

R-1LL — Single‑family Large Lot (Hillside)

  • Purpose & typical uses: R-1LL addresses hillside, very low density single‑family lots (§ 10.05.0500 – .0510) .
  • Key dimensional standards:
    • Minimum lot width: 50 ft interior, 60 ft corner (§ 10.05.0520) .
    • Minimum lot area: 10,000 sq ft (§ 10.05.0520) .
    • Lot coverage: 40% (§ 10.05.0520) .
    • FAR: 55% (with detailed counting rules for crawlspaces, attics, decks; exceptions for steep slopes) (§ 10.05.0520) .
    • Height: 30 ft with roof slope requirement (see R-1 for slope rule); height exceptions and variances addressed in the code (§ 10.05.0520) .
  • Practical: the code explicitly allows FAR exceptions for steep lots and lots with easements through planning commission action (§ 10.05.0520) .

R-2 — Duplex/Triplex Residential

  • Purpose & typical uses: R-2 permits duplexes and triplexes, with accessory uses and ADUs allowed (§ 10.05.0710) .
  • Key dimensional standards:
    • Minimum lot width: 50 ft interior, 60 ft corner (§ 10.05.0720) .
    • Minimum lot area: 5,000 sq ft interior; 6,000 sq ft corner; 7,500 sq ft for triplexes (§ 10.05.0720) .
    • Lot coverage: (see § 10.05.0720) — coverage rules vary by building type (duplex/triplex) and are in the code text .
    • Height: 40 ft maximum for many multifamily districts; exceptions/variance process described in § 10.05.0720 (see airport consistency language) .
    • Setbacks: front 20 ft; side yards generally expressed as a percentage of lot width (interior side: min 5% of lot width but not less than 5 ft and in some cases raised with height); rear setbacks scale up with building height (§ 10.05.0720) .
    • Density: minimum lot area per unit 1,000 sq ft in some multifamily contexts; verify exact subsection depending on unit type (§ 10.05.0820 and § 10.05.0720) .
  • Practical: interior side setbacks increase as building height increases; garages and driveway maneuvering also have minimum location rules (§ 10.05.0720) .

R-3 — Multifamily Residential

  • Purpose & typical uses: R-3 allows apartments and higher‑density housing (§ 10.05.0810) .
  • Key dimensional standards:
    • Minimum lot width/area: 50 ft interior, 60 ft corner; 5,000 sq ft interior lot area (corner lots have different thresholds) (§ 10.05.0820) .
    • Lot coverage: 75% (§ 10.05.0820) .
    • FAR: No limit stated for this district; the code text indicates FAR may be “no limit” for R‑3 (§ 10.05.0820) .
    • Height: 40 ft maximum (with exceptions/variance process) and airport consistency requirements apply (§ 10.05.0820) .
    • Setbacks: front 20 ft; side yards are a percentage of lot width (minimums and increases with height are specified); rear minimums start at 5 ft and scale with height (§ 10.05.0820) .
  • Practical: because FAR is unrestricted in the code language snippet, other controls (setbacks, lot coverage, design review, and specific plan standards) will be the limiting factors; confirm with planning staff for large projects (§ 10.05.0820) .

C — Commercial

  • Purpose & typical uses: C district allows a broad set of commercial uses (retail, offices, lodging, food) and accessory residential uses where listed (§ 10.05.1010 and 10.05.1020) .
  • Key dimensional standards:
    • Minimum lot width: 25 ft; minimum lot area: 2,500 sq ft (§ 10.05.1020) .
    • Lot coverage: 100% allowed (§ 10.05.1020) .
    • FAR: No limit stated for C (§ 10.05.1020) .
    • Height: 40 ft maximum (height exceptions and variances described in § 10.05.1020); airport land‑use compatibility (ALUC) rules apply (see Article XVI) .
    • Setbacks: generally none in C, except 10 ft where adjacent to an alley or any R district; garage entrance location rules apply (§ 10.05.1020) .
  • Practical: downtown commercial parcels often have full lot coverage and limited setbacks; parking requirements still apply (see the Millbrae Parking rules and MMC § 10.05.2100) .

I — Industrial

  • Purpose & typical uses: I district covers manufacturing, warehousing, and industrial support uses (§ 10.05.1210 – .1220) .
  • Key dimensional standards:
    • Minimum lot width: 100 ft; minimum lot area: 10,000 sq ft (§ 10.05.1220) .
    • Lot coverage: 50% (§ 10.05.1220) .
    • FAR: None (no stated limit in excerpt) (§ 10.05.1220) .
    • Height: 40 ft maximum (exceptions and variance process described) (§ 10.05.1220) .
    • Setbacks: front 25 ft, side 10 ft, rear as specified in the code (§ 10.05.1220) .

DTECRSP — Downtown & El Camino Real Specific Plan

  • Purpose & typical uses: the DTECRSP district is a specific plan for transit‑oriented, mixed‑use redevelopment; permitted and conditional uses are governed by the Specific Plan as well as the zoning chapter (§ 10.05.1100 – .1120) .
  • Key dimensional standards:
    • Development standards (setbacks, parking, heights, FAR) are those specified in the downtown and El Camino Real Specific Plan and are cross‑referenced in § 10.05.1120; applicants must consult the Specific Plan document in addition to MMC § 10.05.1120 (§ 10.05.1120) .
  • Practical: Specific Plan controls supersede or add to base zoning standards; prepare a plan‑level submittal (site development plan) for projects in this area (§ 10.05.1120) .

MSASP / MSAPD — Millbrae Station Area Specific Plan / Planned District

  • Purpose & typical uses: Station area is regulated by the Millbrae Station Area Specific Plan (MSASP); new structures there require a detailed site development plan (§ 10.05.1715 – .1720) .
  • Key dimensional standards:
    • The MSASP contains its own development standards (heights, FAR, setbacks, parking). MMC requires that any MSAPD use comply with the MSASP development standards and that new buildings submit a site development plan with detailed dimensional tables and design elements (§ 10.05.1715, § 10.05.1720) .
  • Practical: the MSASP approval and site development plan process is administrative + planning commission review; conforming to the MSASP design guidelines is required (§ 10.05.1715) .

Quick decision table (most-decision‑relevant standards)

District Permitted / Typical Uses Lot min (width / area) Lot coverage / FAR Height Setback highlights Code Reference
R-1 Single‑family; ADUs allowed 50 ft / 5,000 sf 50% / 55% FAR 30 ft (slope rules) Front 20 ft; side/rear rules vary by height § 10.05.0620
R-1LL Low-density hillside SF 50/10,000 sf 40% / 55% 30 ft (slope rule) Special slope-related setbacks; see text § 10.05.0520
R-2 Duplex/triplex 50/5,000 sf (triplex 7,500) See code 40 ft typical Front 20 ft; interior side = % of lot width; rear increases with height § 10.05.0720
R-3 Apartments 50/5,000 sf 75% / FAR: no limit (code) 40 ft Front 20 ft; side/rear scale with height § 10.05.0820
C Commercial uses 25 ft / 2,500 sf 100% / no FAR limit 40 ft Typically no setbacks except 10 ft adjacent to alleys or R districts § 10.05.1020
I Industrial 100 ft / 10,000 sf 50% / none 40 ft Front 25 ft; side 10 ft § 10.05.1220
DTECRSP Mixed-use (per plan) Per Specific Plan Per Specific Plan Per Specific Plan Per Specific Plan § 10.05.1120
MSASP / PD Station-area mixed uses Per MSASP / Precise Plan Per MSASP Per MSASP Per MSASP; site development plan required § 10.05.1715 – .1720

How these standards interact in practice (plain-English guidance)

  • Ground Rule: Start with the district that applies to your parcel (see the official zoning map — verify with staff) and read the district’s development standards (lot sizes, coverage, FAR, height, setbacks). The district rules are the baseline; where a Specific Plan (DTECRSP or MSASP) applies, the Specific Plan controls in addition to or instead of base zoning (§ 10.05.1120, § 10.05.1715) .
  • Design review: many projects must pass design review and site plan requirements; the planning commission evaluates compliance with development standards and guidelines — see Millbrae Design Review and MMC §§ 10.05.2500 et seq. (§ 10.05.2500) .
  • Parking and maneuvering: even if a district allows high lot coverage, vehicle parking and garage entrance location rules are enforced (see the Millbrae Parking requirements and MMC § 10.05.2100 referenced in multiple district sections) (§ 10.05.1020, § 10.05.0720) .
  • Airport land‑use: multiple district sections direct you to comply with the San Francisco International Airport compatibility rules (Article XVI). Projects near approach surfaces may trigger noise/avigation requirements — see the cross‑references in each district standard (§ 10.05.0620, § 10.05.0720, § 10.05.1020) .
  • ADUs: accessory dwelling units are listed as accessory uses in residential districts; separate Millbrae and State ADU standards may apply — see Millbrae ADUs and the city ADU provisions in the code (ADU specifics not fully repeated in the development standards sections above) (§ 10.05.0620, § 10.05.0720) .
  • Building code: dimensional and zoning compliance is distinct from construction compliance under Title 24; you must meet both sets of rules.

Checklist (what an applicant must satisfy)

  • Determine zoning for the parcel and confirm district (verify zoning map with staff).
  • Confirm applicable Specific Plan or overlay (DTECRSP, MSASP, PD, airport overlay) and read its standards (§ 10.05.1120, § 10.05.1715) .
  • Calculate lot‑area, lot‑width, lot coverage, and FAR per district rules and FAR counting rules (attics, crawlspaces, decks) (§ 10.05.0620, § 10.05.0520) .
  • Confirm building height limits and any roof‑slope exceptions; determine whether a height exception or variance will be needed (§ 10.05.0620, § 10.05.1020) .
  • Verify setbacks for all floors (ground and upper) and any projection/encroachment rules for porches, eaves and balconies (§ 10.05.0520, § 10.05.0720) .
  • Prepare parking calculations per MMC § 10.05.2100 and show maneuvering area and garage distances (§ 10.05.1020, § 10.05.0720) .
  • For projects in downtown / station area, prepare a site development plan and MSASP/DTECRSP compliance package (§ 10.05.1715, § 10.05.1720) .
  • Check design review triggers and prepare required drawings/materials for planning commission review (Millbrae Design Review) (§ 10.05.2500) .
  • Confirm ALUC/airport compatibility (Article XVI) and that required notices/easements are handled (§ 10.05.0620, § 10.05.1020) .
  • Verify ADU rules if proposing accessory units and coordinate with State ADU law where relevant (California ADU law) — specifics in the code may be in other sections (see ADU references in district use lists) (§ 10.05.0620, § 10.05.0720) .
  • Confirm whether variances, height exceptions, or conditional use permits are required and plan for public hearing timelines (§ 10.05.0720, Article XXV references) .

Risks & Ambiguities

Issue Why it matters What to verify
Zoning map / district boundary Standards differ substantially by district; applying wrong district leads to noncompliance Verify parcel zoning and any overlay or Specific Plan designation with the City (zoning map). Not found in retrieved materials.
FAR counting rules (attics, crawlspaces, decks) FAR is defined with detailed counting rules that change usable floor area calculations Use the FAR counting rules in § 10.05.0620 and related district language when calculating; confirm with planning staff (§ 10.05.0620)
Airport Land Use (Article XVI) specifics Projects near SFO may face strict height/avigation/noise conditions that can alter usable building envelope Text of Article XVI (ALUC procedures, noise mitigation) was referenced but full Article XVI language is Not found in retrieved materials; verify exact ALUC requirements with the city (§ 10.05.0620, § 10.05.1020)
Specific Plan controls (DTECRSP / MSASP) Specific Plan controls can supersede base zoning for heights, FAR, and design Consult the full DTECRSP / MSASP documents and § 10.05.1120 / § 10.05.1715; plan standards not fully replicated in the zoning sections (§ 10.05.1120, § 10.05.1715)
Parking calculations vs. lot coverage Full lot coverage does not remove parking requirements; lack of on‑site parking can trigger conditional use review Confirm parking requirement table (§ 10.05.2100) and cross‑check with MMC references in each district (e.g., § 10.05.1020)
ADU interplay with SB9 / two‑unit rules Some code sections limit ADUs when an SB9/two‑unit development is proposed SB9 / two‑unit rules are in MMC §§ 10.05.3545 – .3550; note ADU prohibitions for some two‑unit developments (§ 10.05.3545, § 10.05.3550)

Information Gaps

  • Official zoning map and parcel‑specific district boundaries: Not found in retrieved materials — Verify with the City of Millbrae planning counter.
  • Full text of Article XVI (Airport Land Use Compatibility Plan Consistency): referenced by many district sections but the Article XVI text and exact § number were Not found in retrieved materials. (§ references to Article XVI appear in district sections) .
  • Full parking standards table (MMC § 10.05.2100) body: the district sections reference the table, but the table text was not returned in the retrieved snippets — consult MMC § 10.05.2100 directly. .
  • Complete Specific Plan numeric controls (DTECRSP / MSASP): the zoning code points to the Specific Plan documents for actual numeric heights/FARs in those areas — the full Specific Plan texts are not in the retrieved file set (§ 10.05.1120, § 10.05.1715) .

Plain‑English Summary

Millbrae’s zoning rules set district‑specific minimum lot widths/areas, lot coverage caps, FAR counting rules, height caps (often 30–40 ft depending on district), and setback tables that change with building height; commercial and downtown specific plan areas have very different rules (often full lot coverage and plan‑level standards). Always check the parcel’s base zone and any Specific Plan or airport overlay first, then run setback/coverage/FAR math and the parking test before preparing design review materials. Key enforcement language appears in each district’s development standards (example: § 10.05.0620 for R‑1) .

Source References

  • Millbrae Municipal Code — R‑1 Development Standards: § 10.05.0620 .
  • Millbrae Municipal Code — R‑1LL Development Standards: § 10.05.0520 .
  • Millbrae Municipal Code — R‑2 Development Standards: § 10.05.0720 .
  • Millbrae Municipal Code — R‑3 Development Standards: § 10.05.0820 .
  • Millbrae Municipal Code — Commercial (C) Development Standards: § 10.05.1020 .
  • Millbrae Municipal Code — Industrial (I) Development Standards: § 10.05.1220 .
  • Millbrae Municipal Code — Downtown & El Camino Real Specific Plan: § 10.05.1120 .
  • Millbrae Municipal Code — Millbrae Station Area Specific Plan site development plan: § 10.05.1715, § 10.05.1720 .
  • Millbrae Municipal Code — SB9 / two‑unit objective standards: § 10.05.3545 – .3550 .
  • Millbrae Municipal Code document source (ecode360 download): https://ecode360.com/MI4538 (downloaded content used for this summary) .

Sources

Retrieved passages

  • Millbrae Zoning Code (§ 7906) High relevance
  • Millbrae Zoning Code (§ 7909) High relevance
  • Millbrae Zoning Code (§ 8132) High relevance
  • Millbrae Zoning Code (§ 10.05.0500.) High relevance
  • Millbrae Zoning Code (Article XXV) High relevance
  • Millbrae Zoning Code (Article XVI) High relevance
  • Millbrae Zoning Code (Article XVI) High relevance
  • Millbrae Zoning Code (Article II) High relevance

Cited sections

Frequently asked questions

What can I build on an R-1 lot in Millbrae?

On a R‑1 parcel you may build a detached single‑family dwelling and customary accessory uses (including ADUs as allowed by the ADU chapter). Development must meet R‑1 lot, coverage, FAR and setback rules found at § 10.05.0620 and comply with design review if triggered.

What are Millbrae setback requirements for single‑family homes?

Setbacks for single‑family homes in the R‑1 district include a 20 ft front yard and side/rear yards set per § 10.05.0620; upper‑floor setbacks may increase with height and specific encroachment rules apply for porches/eaves. See § 10.05.0620 for full tables and permitted projections.

How is FAR calculated in Millbrae?

FAR is defined in Article II and district sections (for example § 10.05.0620) provide detailed counting rules: certain attics, crawlspaces, covered decks and large porches may be counted fully or partially toward FAR. Read the FAR counting list in § 10.05.0620 when you calculate allowable floor area.

What are the height limits in Millbrae zoning districts?

Typical height caps are 30 ft in low‑density residential (with roof slope exceptions) and 40 ft in many multifamily/commercial/industrial zones; exceptions or variances are available through the planning commission or variance process (see district § language, e.g., § 10.05.0620, § 10.05.1020).

Do I need design review for a new residential addition?

If your project alters the exterior and is subject to planning commission review, design review rules apply; the code sets the required submittals and the findings the commission uses (§ 10.05.2500). Check Millbrae Design Review and § 10.05.2500 for required materials and findings.

How do airport (SFO) rules affect building height or use?

Most district development standards include a cross‑reference to the Airport Land Use Compatibility Plan (Article XVI). Projects near SFO must satisfy ALUC noise, avigation, safety and airspace evaluation requirements; the districts explicitly direct applicants to Article XVI in multiple places (e.g., § 10.05.0620, § 10.05.1020). See those cross‑references and verify Article XVI with city staff.

Are parking requirements separate from lot coverage rules?

Yes. Lot coverage and FAR control building size, while parking requirements are set in the parking table (MMC § 10.05.2100) referenced in each district (e.g., § 10.05.1020, § 10.05.0720). Full lot coverage does not exempt you from providing required parking and maneuvering.

Can I get a height exception or variance?

Height exceptions (for chimneys, cupolas, similar appurtenances) and variances for exceeding height limits are provided for in district sections and in the ordinance’s variance procedures (district examples: § 10.05.0620, § 10.05.1020). The planning commission may grant some height exceptions under specified conditions; other increases require a variance.

What if my parcel is in the Downtown or Station Area Specific Plan?

Projects in the DTECRSP or MSASP are governed by their Specific Plan standards (setbacks, heights, FAR, parking). MMC cross‑references those plans and requires site development plan submittals for MSASP projects (§ 10.05.1120, § 10.05.1715). Prepare the Specific Plan compliance materials accordingly.

Does Millbrae limit FAR in R‑3 or commercial zones?

The code excerpts show no stated FAR limit for some higher‑density districts (for example R‑3 and C excerpts indicate “no limit” or “none”); however, other controls (lot coverage, setbacks, design review, Specific Plan limits) effectively limit intensity — always verify with planning staff for large projects (§ 10.05.0820, § 10.05.1020).

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