Los Altos Hills — Land Use

Last reviewed: July 2, 2026

Overview

This page summarizes what the Town of Los Altos Hills zoning ordinance (Title 10) actually allows and requires for land use in the town. It is focused on the local land‑use rules: permitted primary uses, accessory uses, conditional uses, prohibited uses, and the key development/dimensional controls that apply by district. All requirements below are grounded in the Los Altos Hills Municipal Code and cited to the controlling sections (§) of Title 10.

Key takeaways (quick)

• The town’s base residential zone is R‑A (Residential‑Agricultural); primary uses include single‑family dwellings and agriculture (§ 10‑1.701).
• The OSR (Open Space Reserve) district prioritizes agriculture, forest preserves and open space (§ 10‑1.801).
• Many otherwise uncommon uses (e.g., churches, libraries, schools, town facilities, fire/police stations, commercial stables) are allowed only as conditional uses in R‑A and require a permit process and findings (§ 10‑1.703; § 10‑1.1001–1009).
• Dimensional and development controls (minimum parcel size, Maximum Development Area, setbacks, height, Maximum Floor Area) are handled in Article 5 (§ 10‑1.501–10‑1.506; § 10‑1.502).
• Off‑street parking rules apply and conditional uses must provide sufficient parking; see Article 6 and R‑A parking references (§ 10‑1.705; § 10‑1.601).

District‑by‑district breakdown

R‑A (Residential‑Agricultural)

Purpose / overview

• The R‑A district is the Town’s primary residential/agricultural zone. Purpose and permitted primary uses focus on low‑density homes and agriculture (§ 10‑1.701).

Typical permitted PRIMARY uses

• Primary dwellings (one primary dwelling per lot as a general rule) and agriculture are explicitly permitted (§ 10‑1.701).
• Emergency shelters, employee/farmworker housing, residential care facilities, and transitional/supportive housing are listed as permitted subject to local standards and state licensing where applicable (§ 10‑1.701).

Accessory uses and special permitted items

• Accessory buildings, small family day care homes, household pets, ornamental garden structures, photovoltaic and solar thermal systems, and Accessory Dwelling Units (ADUs) are allowed as accessory uses; ADUs are governed by Article 14 (Article 14 requirements control ADUs) (§ 10‑1.702(k)).
• Temporary trailer coaches during construction are permitted with a zoning permit (§ 10‑1.702(l)).

Conditional uses (examples)

• Uses that may be allowed only after obtaining a conditional use permit include public libraries, churches/places of worship, recreational/community centers, large family day care homes, schools (if the General Plan land use diagram designates them), public utility/service uses, fire/police/town facilities, commercial stables, and certain nonprofit uses when large acreage and open space preservation conditions are met (§ 10‑1.703).

Prohibited uses (not allowed in R‑A)

• The code expressly prohibits commercial cannabis activity and dispensaries in R‑A (limited personal cultivation exceptions per California law) (§ 10‑1.706).

Key dimensional / development controls that apply to R‑A parcels

• Minimum parcel size: 43,560 sq ft as a general rule (§ 10‑1.501).
• Maximum Development Area (MDA) and Maximum Floor Area (MFA) are calculated by formula and depend on lot area, slope, and Lot Unit Factor (LUF) (§ 10‑1.502; § 10‑1.503).
• Height, setbacks, and floor area limits are in Article 5 (see §§ 10‑1.503–10‑1.506 for floor area, height, and setbacks). § 10‑1.704 refers R‑A to Article 5 for specific setbacks.
• Off‑street parking rules for R‑A are in Article 6 and R‑A references § 10‑1.705 (see Article 6 for specific ratios and standards) (§ 10‑1.705; § 10‑1.601).

Practical guidance

• Expect accessory uses like ADUs to be processed under Article 14 rules regardless of other R‑A provisions (§ 10‑1.702(k)).
• Conditional uses require findings about site adequacy, impacts on surrounding uses, traffic and parking adequacy, and public welfare; anticipate conditions to protect health and safety (§ 10‑1.1007; § 10‑1.703).

(See the checklist below for steps applicants must satisfy.)

OSR (Open Space Reserve)

Purpose / overview

• The OSR district preserves agricultural uses, forest preserves, and other open space uses (§ 10‑1.801).

Permitted primary and accessory uses

• Primary: agriculture (horticulture/grazing), forest preserves, and other open‑space uses (§ 10‑1.801).
• Accessory: structures necessary for a permitted primary use (usually non‑habitable structures), and fences/trees subject to height limits (§ 10‑1.802; § 10‑1.504 height reference).

Prohibited uses

• OSR also contains prohibitions on commercial cannabis activity and dispensaries (parallel to R‑A) (§ 10‑1.804).

Practical guidance

• OSR sites are typically constrained for residential development; check Article 5 dimensional standards when any structure is proposed (§ 10‑1.803).

Upper Neary Quarry Lands (special rules)

Purpose / overview

• The code includes a special Article addressing the Upper Neary Quarry Lands (approx. 300 acres) with tailored restrictions and conservation requirements (Article 9 / § 10‑1.901).

Key rules (high level)

• Only one primary dwelling per lot; each lot must have a net area of at least 10 acres in the Quarry Lands. (§ 10‑1.901 and related subsections).
• Development must avoid ridgelines and hilltops; dwelling siting and height are constrained to preserve views and topography. Conservation easements are required as a condition of development in many cases (§ 10‑1.901).
• Maximum development area and floor area on Quarry Lands are limited to those allowed on a one‑acre flat R‑A lot (special limitations tied back to R‑A standards).

Practical guidance

• These parcels carry special ballot‑adopted limits and conservation easement triggers — confirm applicability to any specific parcel before design work. (§ 10‑1.901 et seq.)

Most decision‑relevant standards (quick reference table)

How the rules interact with common application steps (practical notes)

• Confirm the parcel’s zoning designation (R‑A, OSR, or Quarry Lands) on the Town zoning map; the code requires uses to be limited to those listed for the district (§ 10‑1.301–10‑1.309).
• Calculate Lot Unit Factor, Average Slope, and Net Area to derive MDA and MFA before conceptual design — the formulas and related minimum parcel and circle‑size rules are in § 10‑1.501–10‑1.502.
• If proposing any conditional use (e.g., large day care, church, library), build the permit application to address the specific findings in § 10‑1.1007 and the notice/appeal timelines (§ 10‑1.1008–10‑1.1009).
• Use the town’s design review expectations and objective design standards when preparing plans; many conditional and site development permits evaluate aesthetic and rural‑character impacts (see design and site development articles).

Checklist

• Verify parcel zoning (R‑A, OSR, Upper Neary) and any overlay districts (if any) on the Town map.
• Read permitted primary and accessory uses for that district: § 10‑1.701, § 10‑1.702, § 10‑1.801 as applicable.
• Compute net lot area, Lot Unit Factor (LUF), average slope, MDA and MFA per § 10‑1.502 and § 10‑1.503.
• Confirm minimum parcel size and required inscribed circle(s) (§ 10‑1.501).
• Check setback, height and floor area limits in Article 5 (see § 10‑1.504–10‑1.506) and R‑A referral (§ 10‑1.704).
• Determine parking demand under Article 6 and ensure conditional uses meet the adequacy standards (§ 10‑1.601; § 10‑1.705).
• If proposing a conditional use, prepare findings and materials required by § 10‑1.1001 and § 10‑1.1007; include traffic/parking/noise mitigation.
• For ADUs, follow Article 14 requirements (ADUs are governed exclusively by Article 14 per § 10‑1.702(k)).
• Check for any nonconforming‑use rules that might restrict alterations or expansions (Article 4, §§ 10‑1.401–10‑1.406).

Risks & Ambiguities

Plain‑English summary

Most Los Altos Hills lots are in R‑A, where you can build a single‑family home and use the land for small‑scale agriculture, with accessory buildings and ADUs allowed under their specific articles; bigger or non‑residential activities (schools, churches, recreation centers, stables) generally require a conditional use permit and must meet strict findings about site adequacy, parking and neighborhood impacts (§ 10‑1.701–§ 10‑1.706; § 10‑1.1001–10‑1.1009).

Source References

• Los Altos Hills Municipal Code, Title 10 (Zoning & Site Development) — primary code document (ecode360 copy). See the Town code for all text and figures: https://ecode360.com/LO4964.
• R‑A primary/conditional/accessory use rules: § 10‑1.701, § 10‑1.702, § 10‑1.703, § 10‑1.704–10‑1.706.
• Article 5 (Area, coverage, height and setbacks): § 10‑1.501–10‑1.506 (minimum parcel size, development area, height, setbacks).
• Article 6 (Off‑street parking references and R‑A parking): § 10‑1.601, § 10‑1.602, § 10‑1.705.
• Conditional/variance/appeal procedures and findings: § 10‑1.1001–10‑1.1009, § 10‑1.1007.
• Open Space Reserve (OSR) rules: § 10‑1.801–10‑1.804.
• Upper Neary Quarry Lands special rules: Article 9, § 10‑1.901 et seq. (Quarry Lands restrictions and conservation easement rules).
• Nonconforming uses (maintenance, discontinuance, repairs): Article 4, § 10‑1.401–10‑1.406.

Inline links to related local pages and broader rules (first natural mention of each topic above has been linked): parking (/us/california/los-altos-hills/parking), development standards (/us/california/los-altos-hills/development-standards), design review (/us/california/los-altos-hills/design-review), overlay districts (/us/california/los-altos-hills/overlay-districts), ADUs (/us/california/los-altos-hills/adu), nonconforming uses (/us/california/los-altos-hills/nonconforming-uses), variances and exceptions (/us/california/los-altos-hills/variances-and-exceptions), California Building Standards Code (/us/california/building-codes).

Retrieved passages

• Los Altos Hills Zoning Code (§ 1) High relevance show source text
• Los Altos Hills Zoning Code (chapter as) High relevance show source text
• Los Altos Hills Zoning Code (Article 7) High relevance show source text
• Los Altos Hills Zoning Code (§ 1) High relevance show source text
• Los Altos Hills Zoning Code (§ 10-1.902.) High relevance show source text
• Los Altos Hills Zoning Code (§ 1) High relevance show source text
• Los Altos Hills Zoning Code (§ 10-1.703) High relevance show source text
• Los Altos Hills Zoning Code (§ 10-1.702) High relevance show source text

Cited sections

• Los Altos Hills Municipal Code, Title 10 (Zoning & Site Development) — primary code document (ecode360 copy). See the Town code for all text and figures: (Title 10)
• **R‑A** primary/conditional/accessory use rules: **§ 10‑1.701**, **§ 10‑1.702**, **§ 10‑1.703**, **§ 10‑1.704–10‑1.706**. (§ 10)
• Article 5 (Area, coverage, height and setbacks): **§ 10‑1.501–10‑1.506** (minimum parcel size, development area, height, setbacks). (Article 5)
• Article 6 (Off‑street parking references and R‑A parking): **§ 10‑1.601**, **§ 10‑1.602**, **§ 10‑1.705**. (Article 6)
• Conditional/variance/appeal procedures and findings: **§ 10‑1.1001–10‑1.1009**, **§ 10‑1.1007**. (§ 10)
• Open Space Reserve (OSR) rules: **§ 10‑1.801–10‑1.804**. (§ 10)
• Upper Neary Quarry Lands special rules: Article 9, **§ 10‑1.901** et seq. (Quarry Lands restrictions and conservation easement rules). (Article 9)
• Nonconforming uses (maintenance, discontinuance, repairs): Article 4, **§ 10‑1.401–10‑1.406**. (Article 4)
• LosAltosHills_ZoningCode.md

• Official Los Altos Hills code library