Local zoning · Los Altos
Los Altos — Zoning
Zoning under the Los Altos local zoning and planning code, with the controlling citations.
Last reviewed: July 2, 2026
Overview
This page summarizes what the City of Los Altos Zoning Code (Title 14) actually says about zoning districts, the official zoning map, and the development rules that apply inside each district. For the city's general menu and where to start, see the Los Altos zoning & planning overview. Key cross-cutting topics referenced below include development standards, parking, design review, overlays, and ADUs; specific links and the controlling code sections are cited next to the rules they govern.
How to read this page
- Bolded terms are the actual Los Altos district names used in the code (for example, R1-10, CT, PCF).
- Every numeric requirement is tied to the ordinance with a § citation; the underlying file excerpts used here are cited inline using the file-search citation markers returned from the municipal code export. Verify parcel-specific questions with the City — see the “Risks & Ambiguities” checklist.
District-by-district breakdown
R1-10 (Single‑Family District)
Purpose: Preserve typical single‑family lots and small‑lot neighborhoods; controls density and form in areas shown as Residential 2/3 in the General Plan. (§ 14.06.010)
Typical permitted uses: single‑family residences, accessory dwelling units (ADUs) as regulated in Chapter 14.14, home occupations, limited agriculture, and small family day care. (§ 14.06.020)
Key dimensional standards (common decision points):
- Minimum site area: 10,000 sq ft (corner lots 11,000 sq ft, flag lots 15,000 sq ft) (§ 14.06.040)
- Lot width/frontage: 80 ft (corner 90 ft) (§ 14.06.050)
- Maximum lot coverage: 35% for structures >6 ft; if coverage >30% then two‑story buildings are prohibited (§ 14.06.060)
- FAR / maximum floor area: 35% for lots ≤11,000 sq ft; formula for larger lots (§ 14.06.070)
- Setbacks: Front 25 ft; Interior side 1st story 10 ft / 2nd story 17.5 ft; Exterior side 20 ft; Rear 25 ft (§ 14.06.080)
- Height limit: 2 stories or 27 ft (flag lots limited to 1 story / 20 ft; lower height if lot coverage rules trigger) (§ 14.06.090)
Where it applies: Most single‑family neighborhoods designated in the General Plan as Residential 2/3; official boundaries are those shown on the city zoning map (the map is incorporated by reference into Title 14). (§ 14.04.010; § 14.04.020)
Practical note: ADUs are permitted but must meet the ADU chapter; see the ADU page for ministerial standards and separate rules. (/us/california/los-altos/adu)
R1-H (Single‑Family, Hillside)
Purpose: Preserve large‑lot hillside/residential character and offer variable lot area rules where topography or neighborhood pattern justifies alternative standards. (§ 14.08.010)
Typical permitted uses: Similar to R1-10 (single‑family primary plus accessory structures and ADUs where allowed). (§ 14.08.020–.030)
Key dimensional standards:
- Minimum site area: typically 10000+ sq ft but reduction can be approved by commission under findings; see § 14.08.040–.050. (§ 14.08.040–.050)
- Coverage: 25% maximum coverage (>6 ft) (lots <15,000 sq ft fall back to R1‑10 coverage) (§ 14.08.060)
- Setbacks: Front 30 ft; Interior side 1st story 20 ft (25 ft if height>22 ft); Rear 50 ft (§ 14.08.080)
Where it applies: Localized hillside neighborhoods identified in the zoning map and General Plan; check official map or rezoning ordinances. (§ 14.04.010; various rezoning entries in § 14.88)
R1-20 / R1-40 (Single‑Family — larger lot bands)
Purpose: Gradations of single‑family lot sizes (one‑half acre, one acre equivalents) with progressively larger setbacks and lower coverage to preserve greater open area and lower density. (§ 14.04.010)
Key highlights:
- R1-20 front setback: 30 ft; interior side 20 ft first story (25 ft if >22 ft); rear 35 ft; height 2 stories / 27 ft (§ 14.10.080–.090)
- R1-40 front setback: 50 ft; interior side 30 ft; rear 50 ft; coverage 20%; height limits similar (§ 14.12.080; § 14.12.060)
Where it applies: Larger‑lot residential areas as shown on the zoning map; rezoning history and map amendments are recorded in the zoning map amendment sections (§ 14.88.*).
R1‑S (Single‑Story Overlay)
Purpose: Single‑Story Single‑Family Overlay District to preserve single‑story character in identified neighborhoods. (§ 14.04.010; Rezoning map entries)
Where it applies: Only to properties identified on the specific rezoning map (e.g., Larkellen Lane — Rezoning Map No. 16‑Z‑02) and incorporated by reference; see rezoning ordinance § 14.88.710. (§ 14.88.710)
Practical note: Overlay district rules or limitations (single‑story requirement) are implemented by local rezoning documents incorporated into Title 14; confirm exact parcels by reviewing the specific rezoning map referenced in § 14.88.*. (§ 14.88.710)
R3‑4.5 / R3‑5 / other R3 (Multiple‑Family)
Purpose: Preserve and manage low‑ to mid‑density multi‑family development; several R3 subcategories exist to reflect neighborhood contexts (e.g., R3‑4.5 retains Stevens Place/Marshall Court character). (§ 14.16.010–.020)
Typical permitted uses: Two‑family units (R3‑4.5), multi‑family housing types as specified in each R3 chapter. (§ 14.16.030 for R3‑4.5; § 14.18.* for R3‑5)
Key dimensional standards (examples):
- R3‑4.5: Min site area 7,000 sq ft; max coverage 60%; FAR 55%; setbacks variable (e.g., first story 5 ft from interior property lines; increased setbacks where abutting R1‑10 or specific streets) (§ 14.16.040–.060; § 14.16.080–.090)
- R3‑5: Min site area 5,000 sq ft; front yard 40 ft; side yards 15 ft (25 ft on corner); rear 30 ft; coverage 60% (§ 14.18.040–.080)
Design control: R3 zones include explicit design/massing and adjacency controls (façade width limits abutting R‑1 districts, articulation requirements) and height caps (e.g., 36 ft / 3 stories in some R3 zones). (§ 14.16.090; § 14.16.100)
Where it applies: Multi‑family corridors and specific neighborhoods indicated on the zoning map; consult the exact R3 subtype for parcel‑level rules. (§ 14.04.010)
OA / OA‑1 / OA‑4.5 (Office‑Administrative)
Purpose: Small‑scale office and administrative uses grouped to respect neighborhood scale; standards referenced in Chapter 14.* for OA districts. (§ 14.04.010)
Typical uses: Office, administrative support uses; parking and signage follow citywide Chapters (14.74, signage chapter). (See OA chapters in Title 14.) Verify parcel‑specific allowances with the zoning map and OA chapter.
CN (Commercial Neighborhood), CD (Commercial Downtown), CRS, CT (Commercial Thoroughfare)
Purpose: Commercial districts vary by intensity — CN is neighborhood retail, CD is downtown mixed commercial/multi‑family, CRS is retail sales, CT is thoroughfare/multi‑story mixed‑use corridor. (§ 14.04.010)
Key items:
- CT heights: residential-only up to 55 ft / 5 stories; mixed‑use up to 60 ft / 5 stories; non‑residential up to 45 ft / 4 stories (§ 14.50.140)
- Parking and loading are governed by citywide rules in Chapter 14.74 — consult the city's parking rules early in project planning. (/us/california/los-altos/parking)
Where it applies: Commercial corridors, downtown core, and specific parcels shown on the zoning map; rezonings and prezoning actions are recorded under § 14.88.. (§ 14.88.)
PC (Planned Community)
Purpose: Sites planned and controlled as unified communities with site‑specific standards set at approval; default single‑family standards may apply depending on lot size. (§ 14.56.070)
Key notes:
- For single‑family lots ≤15,000 sq ft, R1‑10 standards apply; larger lots default to R1‑20 or R1‑40 standards as set out in § 14.56.070(A). (§ 14.56.070)
- The planning commission and council approve PC development standards; check the PC application documents on file with the Planning Department. (§ 14.56.090)
PCF (Public & Community Facilities)
Purpose: Parks, schools, government buildings and other public uses; the City rezones specific parcels into PCF by map amendment. (§ 14.04.010; § 14.88.720)
Typical uses: Community buildings, parks, public facilities; development standards come from the PCF chapter or are set at time of rezoning.
Quick standards table (decision‑relevant snapshot)
| District | Key decision standards (high‑priority) | Code Reference |
|---|---|---|
| R1‑10 | Min site area 10,000 sq ft; Front 25 ft; Coverage 35%; FAR 35% (≤11,000 sf lots); Height 2 stories / 27 ft | § 14.06.040, .060, .070, .080, .090 |
| R1‑20 | Front 30 ft; Interior side 20 ft; Rear 35 ft; Height 2 stories / 27 ft | § 14.10.080–.090 |
| R1‑40 | Front 50 ft; Side 30 ft; Coverage 20%; Rear 50 ft | § 14.12.060–.080 |
| R3‑4.5 | Min site 7,000 sf; Coverage 60%; FAR 55%; setbacks first story 5 ft | § 14.16.040–.060, .080 |
| R3‑5 | Min site 5,000 sf; Front yard 40 ft; Side 15 ft (25 ft when abutting R1) | § 14.18.040–.080 |
| CT (Commercial Thoroughfare) | Residential height 55 ft/5 stories; Mixed‑use 60 ft/5 stories; Non‑residential 45 ft/4 stories; parking per Chapter 14.74 | § 14.50.140; 14.74 |
(These are a selection — always read the full chapter for each district. The zoning map sets which district applies to a parcel; map amendments are recorded under § 14.88.*.)
Checklist
- Confirm the parcel’s current zoning on the official zoning map incorporated into Title 14. (§ 14.04.010; § 14.88.*)
- Verify permitted vs. conditional uses in the applicable district (e.g., R1‑10 permitted uses: single‑family, ADUs, home occupations). (§ 14.06.020)
- Calculate dimensional compliance: lot area, width, setbacks, lot coverage, FAR, and height per the district chapter. (See district §§ cited above.)
- Check for overlays (e.g., R1‑S, LCSPZ) or special plan requirements that modify base standards. (/us/california/los-altos/overlay-districts)
- Review ADU rules in Chapter 14.14 for accessory dwelling development and separate ADU limitations. (/us/california/los-altos/adu)
- Confirm parking requirements and any transit/parking reductions early (Chapter 14.74). (/us/california/los-altos/parking)
- Determine whether project triggers design review or discretionary hearings; if so, anticipate architecture/site approval. (/us/california/los-altos/design-review)
- If requesting deviations, follow variance or density bonus procedures (see Chapters 14.81 and 14.28). (/us/california/los-altos/variances-and-exceptions)
Risks & Ambiguities
| Issue | Why it matters | What to verify |
|---|---|---|
| Zoning map boundary uncertainty | Map lines may follow centerlines, property lines, or map scale — boundaries control which district applies. (§ 14.04.020) | Verify parcel boundary vs. zoning map; request clarification from the Zoning Administrator if unclear. |
| Overlay / rezoning documents incorporated by reference | Overlays (e.g., R1‑S, LCSPZ) modify base standards; the overlay applies only where the rezoning map and ordinance list parcel APNs. (§ 14.88.710; § 14.04.010) | Confirm the specific rezoning map (Rezoning Map No. X‑Z‑YY) that applies to the parcel; read the rezoning ordinance. |
| Nonconforming structures / reconstruction rules | Rebuilding thresholds can require bringing structures into conformance when >50% of floor area is rebuilt. This affects remodel strategies. (See nonconforming rules and § 14.64.110) | Confirm what portion of the structure triggers full conformance and whether ministerial approvals are impacted. |
| Parcel-specific PUD/PC standards | Planned Community (PC) and PUD approvals set site‑specific development standards that override baseline district rules. (§ 14.56.070; project files on record) | Review the adopted PC/PUD documents on file with the Planning Department. |
| Density bonus / concessions | State density bonus entitlements and local implementation may change FAR, coverage, and height limits for qualifying affordable units. (§ 14.28.050; density bonus concessions) | If claiming a density bonus, submit required density bonus report and justify requested concessions/waivers. (§ 14.28.050) |
Plain‑English Summary
Los Altos uses a detailed Title 14 zoning code that assigns each parcel to a named district (for example, R1‑10, R3‑4.5, CT). Each district chapter states what you can build there (permitted uses), and lists the measurable development limits — minimum lot size, front/side/rear setbacks, lot coverage, floor‑area rules, and height. Overlays, rezoning ordinances, or a Planned Community approval can change those rules for specific parcels; check the zoning map and the specific rezoning documents the city incorporated by reference. (§ 14.04.010; § 14.88.*; district chapters cited above)
Source References
- Los Altos Municipal Code — Title 14, Zoning (print export). Key district designations: § 14.04.010.
- R1‑10 single‑family district chapters and standards: § 14.06.010–.100.
- R1‑20 district standards: § 14.10.070–.090.
- R1‑40 district standards: § 14.12.060–.080.
- R1‑H district standards: § 14.08.050–.080.
- R3 districts: § 14.16.010–.100 (R3‑4.5) and § 14.18.040–.090 (R3‑5).
- Commercial / CT district: § 14.50.140–.150.
- Zoning map amendments and rezoning attachments incorporated by reference: Chapter 14.88 (§ 14.88. examples: § 14.88.700–.740)*.
- Density bonus and concessions (local implementation): § 14.28.050.
- Variances: Chapter 14.81 (§ 14.81.010–.040).
- ADU rules and related projections: Chapter 14.14 (see § 14.14.080–.090 for projections and general provisions). (/us/california/los-altos/adu)
- Design standards and objective standards references: Chapter 14.64 (objective design, nonconforming rules).
Sources
Retrieved passages
- Los Altos Zoning Code (§ 1) High relevance
- Los Altos Zoning Code (§ 10-2.3445) High relevance
- Los Altos Zoning Code (§ 10-2.3432) High relevance
- Los Altos Zoning Code (§ 2) High relevance
- Los Altos Zoning Code (§ 10-2.3416) High relevance
- Los Altos Zoning Code (§ 10-2.3406) High relevance
- Los Altos Zoning Code (§ 10-2.3427) High relevance
- Los Altos Zoning Code (§ 10-2.3413) High relevance
- Los Altos Zoning Code (§ 3) High relevance
- Los Altos Zoning Code (§ 2) High relevance
- Los Altos Zoning Code (§ 4) High relevance
- Los Altos Zoning Code (§ 1) High relevance
- Los Altos Zoning Code (§ 4) High relevance
- Los Altos Zoning Code (§ 1) High relevance
- Los Altos Zoning Code (Chapter 14.06.) High relevance
- Los Altos Zoning Code (§ 10-2.802.1) High relevance
Cited sections
- Los Altos Municipal Code — Title 14, Zoning (print export). Key district designations: **§ 14.04.010**. (Title 14)
- **R1‑10** single‑family district chapters and standards: **§ 14.06.010–.100**. (§ 14.06.010)
- **R1‑20** district standards: **§ 14.10.070–.090**. (§ 14.10.070)
- **R1‑40** district standards: **§ 14.12.060–.080**. (§ 14.12.060)
- **R1‑H** district standards: **§ 14.08.050–.080**. (§ 14.08.050)
- **R3** districts: **§ 14.16.010–.100** (R3‑4.5) and **§ 14.18.040–.090** (R3‑5). (§ 14.16.010)
- Commercial / CT district: **§ 14.50.140–.150**. (§ 14.50.140)
- Zoning map amendments and rezoning attachments incorporated by reference: **Chapter 14.88 (§ 14.88.* examples: § 14.88.700–.740)**. (Chapter 14.88)
- Density bonus and concessions (local implementation): **§ 14.28.050**. (§ 14.28.050)
- Variances: **Chapter 14.81 (§ 14.81.010–.040)**. (Chapter 14.81)
- ADU rules and related projections: **Chapter 14.14** (see § 14.14.080–.090 for projections and general provisions). (/us/california/los-altos/adu) (Chapter 14.14)
- Design standards and objective standards references: **Chapter 14.64** (objective design, nonconforming rules). (Chapter 14.64)
- LosAltos_ZoningCode.md
Frequently asked questions
What can I build on an R1‑10 lot in Los Altos?
In R1‑10 you may build a single‑family residence, accessory structures and ADUs (subject to Chapter 14.14), home occupations, limited agriculture and small family day care as permitted uses; certain uses can be allowed via a use permit. See § 14.06.020–.030 for the full list and conditions.
What are Los Altos setback requirements for single‑family lots?
Setbacks depend on the R1 subtype. For R1‑10 the code sets Front 25 ft; Interior side 1st story 10 ft / 2nd story 17.5 ft; Exterior side 20 ft; Rear 25 ft (with additional rules for narrow and flag lots). See § 14.06.080.
Do I need design review in Los Altos?
Design review triggers depend on the project and district. Several districts (especially multi‑family and PC/PUD projects) require architectural/site approval or design control under their chapters (see for example the R3 and PC chapters). Confirm with the Development Services Director or zoning administrator; see the Design Review page and relevant district chapters (e.g., § 14.16.100 for design control measures). (/us/california/los-altos/design-review)
How do I know which zoning district applies to my parcel?
The City’s official zoning map is incorporated into Title 14 and the district list is in § 14.04.010. Where boundaries are unclear the code provides rules for interpreting map lines (boundaries follow centerlines or property lines as indicated) and the planning commission can resolve disputes. See § 14.04.020.
Can I build an ADU in Los Altos and what rules apply?
ADUs are authorized by Chapter 14.14; the ADU chapter contains size limits, projection allowances, and ministerial rules. ADU development must also meet underlying district development standards unless specific ministerial ADU provisions say otherwise. See Chapter 14.14 and § 14.14.080–.090. (/us/california/los-altos/adu)
If my property is in an overlay (like R1‑S), which rules control?
The overlay rules and the rezoning ordinance that created the overlay are incorporated by reference into Title 14. The overlay applies only to the parcels identified in that rezoning map (see the rezoning entry in § 14.88.710 for the Larkellen Lane R1‑S example). If the overlay conflicts with base district standards, the overlay ordinance text controls for those parcels. See § 14.88.710 and § 14.04.010. (/us/california/los-altos/overlay-districts)
What happens if my proposed remodel exceeds 50% of an existing unit’s floor area?
Title 14 contains thresholds that, when exceeded, require the rebuilt portion to meet current setback and other zoning requirements; see the nonconforming and rebuild provisions in the applicable chapter (for many districts the 50% threshold is referenced; see e.g., § 14.16.080(C) and related nonconforming rules). Verify district chapter and Chapter 14.64 for details.
If I need a variance, what can I ask for and what can’t I?
A variance may request deviations from Title 14 development standards (height, yards, lot area, setbacks, signs and parking) but not authorization of uses or activities not allowed in the zone. Variance procedures and findings are in Chapter 14.81. (§ 14.81.020–.040)
Where are the official rezoning/rezoning‑map documents recorded?
Rezoning map amendments (the parcels rezoned and the map number) are recorded in Chapter 14.88; each rezoning entry states the rezoning map number and that the map is incorporated by reference. See multiple entries in § 14.88. (examples § 14.88.150–.740)*. ---
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