Local zoning · Los Altos Hills

Los Altos Hills — Historic Preservation

Q: Which permit rules apply first — a zoning permit or a site development permit — for work on a historic parcel?

Zoning permits are required for the uses listed in § 10-1.310 ; site development permit thresholds and whether the project is ministerial or discretionary are defined in § 10-2.301 . Historic status does not eliminate permit triggers — it usually affects eligibility (e.g., SB 9) or referral/review.

Historic Preservation under the Los Altos Hills local zoning and planning code, with the controlling citations.

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Last reviewed: July 2, 2026

Overview

This page summarizes how the Town of Los Altos Hills' local zoning and site development ordinance treats historic preservation, designation, and review for projects — focused only on the Town code, not state building permits or Housing code. For a quick gateway to the Town’s materials, see the Los Altos Hills zoning & planning overview. The ordinance does not create a separate, full historic-code chapter; instead, historic status appears as a factor in specific permit rules (SB 9 eligibility, ADU parking, exemptions, nonconforming-structure treatment, and committee referral/notice) handled through the Town’s zoning and site development provisions.

Note: this page explains what the Town code says; parcel-specific conclusions should be verified with the Town. Relevant procedural rules (permits, findings, referrals) are in the Town Zoning & Site Development ordinance; see the Town’s zoning page for broader context.

How the code treats "historic" property — at a glance

Parcels that are within a Town or County landmark or within an identified historic district receive special treatment in several discrete code sections rather than a single historic-preservation chapter: notable examples include SB 9 exclusion, an ADU parking exemption, an exemption from the Town’s Water Efficient Landscape Ordinance, and special consideration for nonconforming/historic structures. See § 10-1.1503, § 10-1.1403, § 10-2.809, and § 10-1.401 for the controlling language and referral/notice rules in the site development process at § 10-2.301.

District-by-district implications for historic property

Note: the Town uses conventional district names in Title 10. The ordinance treats historic status as an overlay-style attribute (a parcel "located within an historic district" or "designated/listed as a Town or Santa Clara County landmark") that modifies or limits certain actions in any underlying district. Below are the districts most implicated in historic-preservation provisions of Title 10.

Residential‑Agricultural (R‑A)

Purpose & where it applies: The R‑A district governs the Town’s residential/agricultural parcels and is the district identified throughout the Title 10 residential rules (primary and accessory uses, development area, floor area, etc.); see § 10-1.701 (primary uses) and related subsections.
Typical permitted uses: single‑family residences and limited accessory uses as set out in § 10-1.701–§ 10-1.706.
Key dimensional standards: area, coverage, height and setback limitations are codified in § 10-1.704; consult that section for the R‑A numeric standards that govern development area and floor area.
Historic-preservation effects in R‑A: A parcel in R‑A that is “located within an historic district” or is a Town/County landmark is explicitly carved out from SB 9 lot‑split eligibility (i.e., SB 9 lot splits are not allowed on these parcels) — see § 10-1.1503(c). Other development permit processes still apply; historic parcels commonly receive committee referrals and additional review under the site development process.

Open Space Reserve (OSR)

Purpose & where it applies: The OSR district preserves open space lands; see § 10-1.801–§ 10-1.804 for permitted primary and accessory uses and restrictions. Historic designation language does not create new OSR uses but may limit development actions if the parcel is also a designated historic resource.
Typical permitted uses: very limited development to protect open space values; see the sections cited above for specifics.
Key dimensional standards: area/coverage/setbacks/height for OSR are stated in § 10-1.803. If a site in OSR is also a listed historic resource, the Town’s site development review and committee referral language applies (see Site Development).

Other District notes (Upper Neary Quarry lands, etc.)

Special-area rules (e.g., Upper Neary Quarry Lands) have their own sections (§ 10-1.901 series). If a parcel in these special areas is also a designated historic resource, the general historic-related carve-outs in Title 10 (SB 9, ADU parking exception, WELO exemption, nonconforming treatment, committee referrals) remain the controlling cross-references. Verify parcel‑specific applicability.

How historic status changes review and permits (decision‑relevant table)

Topic	What the code does / effect	Code Reference
SB 9 lot‑split ineligibility	Parcels within an historic district or listed on the State Historic Resources Inventory or designated as a Town/County landmark are excluded from SB 9 lot split eligibility.	§ 10-1.1503(c)
ADU parking exemption	No parking required for an ADU if the parcel is “located within an architecturally and historically significant historic district.”	§ 10-1.1403(g)(2)(iii)
WELO landscape exemption	Registered local, state, or federal historical sites may be exempt from Water Efficient Landscape (WELO) requirements when landscaping establishes an historical landscape style.	§ 10-2.809(a)(1)
Nonconforming structure / height consideration	The Planning Commission may allow building height in excess of permitted limits when the higher height is appropriate due to the historic nature of the structure (i.e., historic structures are specifically noted for consideration under nonconforming rules).	§ 10-1.401
Site development referrals and committee input	Site development applications may be referred to committees (including the History Committee) and the History Committee receives notice and may participate in hearings for applicable projects.	§ 10-2.1305.1(b)(1) and (b)(6)
Permit required / ministerial vs discretionary review	Site development and zoning permit thresholds still apply to work on historic parcels; check permit triggers in § 10-2.301 and zoning permit rules § 10-1.310.	§ 10-2.301 § 10-1.310

Practical guidance / synthesis

Historic status in Los Altos Hills is not governed by a separate municipal "historic preservation commission" chapter in Title 10; instead the code references historic listing or district status as a criterion or exception inside specific permit rules (SB 9, ADU parking, WELO, nonconforming structure treatment) and routes notice/review through existing Town committees (the History Committee specifically). See § 10-1.1503, § 10-1.1403, § 10-2.809, and § 10-2.1305.1 for the exact mechanisms.
Because the Town’s approach is distributed into permit rules, a homeowner or applicant must check multiple sections rather than a single “historic” chapter. Typical steps (see Checklist) include confirming listing/district status, understanding whether the parcel is SB 9‑ineligible, and planning for committee referrals and possible discretionary review under the site development permit rules. See § 10-2.301 and § 10-2.1305.1 for how proposals are routed and heard.

Checklist

Confirm whether the parcel is in an historic district or listed as a Town or Santa Clara County landmark or on the State Historic Resources Inventory (this status triggers several code provisions). § 10-1.1503
Determine whether the proposed work needs a zoning permit or a site development permit and whether it will be ministerial or discretionary. § 10-1.310, § 10-2.301
If the parcel is historic, verify that SB 9 lot split is not available for the parcel. § 10-1.1503(c)
For ADUs: confirm whether the ADU qualifies for the historic-district parking exemption. § 10-1.1403(g)(2)(iii)
For landscape and restoration where historical landscape style is proposed, check WELO exemption possibilities. § 10-2.809(a)(1)
Expect referral or participation by the History Committee for site development hearings; build time for possible discretionary review and appeals. § 10-2.1305.1(b) and related referral language.
If work affects a legal nonconforming historic structure, review the nonconforming provisions for allowable additions and the Planning Commission’s ability to consider historic character in height findings. § 10-1.401

Risks & Ambiguities

Issue	Why it matters	What to verify
Is the parcel officially designated/listed?	Many code effects (SB 9 ineligibility, ADU parking exemption, WELO exemption) hinge on formal listing or district maps.	Verify actual listing status with the Town and County clerk/assessor and ask for the list/map the Town uses. (Verify with the jurisdiction.) Not found in retrieved materials for a public inventory list.
What constitutes an “architecturally and historically significant historic district”?	The ADU parking exemption uses this phrase; the code does not define the phrase within the snippets retrieved. Ambiguity can change parking requirements.	Request Town interpretation and the map/criteria used to identify such districts. (Verify with the jurisdiction.) Not found in retrieved materials for a precise definition.
Applicability of nonconforming‑height exception	The Planning Commission may allow excess height for historic structures, but the scope and standard of "appropriate due to the historic nature" is discretionary.	If seeking height relief based on historic significance, get early confirmation from the Planning Department and prepare historic documentation. § 10-1.401
Committee recommendations vs. binding conditions	Committees (e.g., History Committee) provide recommendations; it's not automatic that their recommendations control the final decision.	Verify whether a committee recommendation is advisory or incorporated as binding conditions in your case; review § 10-2.1305.1 and the final staff report.

Plain‑English Summary

Los Altos Hills does not have a single consolidated historic‑preservation chapter in Title 10; instead, being in an official historic district or landmark list affects specific permit rules: it can make a parcel ineligible for an SB 9 lot split, qualify an ADU for a parking exemption, permit WELO landscaping exceptions, and lead to additional committee referral and discretionary review under the Town’s site development rules. Check the specific code sections cited and confirm designation status with the Town before you design a project. § 10-1.1503, § 10-1.1403, § 10-2.809, § 10-1.401, § 10-2.1305.1.

Source References

§ 10-1.1503 — SB 9 lot split eligibility exclusions (historic district/landmark language). — eCode360 Los Altos Hills (Town Code), https://ecode360.com/LO4964 (Town of Los Altos Hills Code).
§ 10-1.1403 — ADU general standards and parking exceptions (historic-district exemption). — eCode360 Los Altos Hills.
§ 10-2.809 — Water Efficient Landscape Ordinance exemptions for registered historical sites. — eCode360 Los Altos Hills.
§ 10-1.401 — Nonconforming structures (height and additions; historic‑nature consideration). — eCode360 Los Altos Hills.
§ 10-2.301 — Site development permit thresholds and process (how historic parcels enter review). — eCode360 Los Altos Hills.
§ 10-1.310 — Zoning permit thresholds. — eCode360 Los Altos Hills.
§ 10-2.1305.1 — Fast‑track / referral language and committees (History Committee participation). — eCode360 Los Altos Hills.
Los Altos Hills general zoning & planning materials for context: Los Altos Hills zoning & planning overview. /us/california/los-altos-hills

Sources

Retrieved passages

Los Altos Hills Zoning Code (§ 10-2.701.) High relevance
Los Altos Hills Zoning Code (Section 5020.1) Medium relevance
Los Altos Hills Zoning Code (§ 1) Medium relevance
Los Altos Hills Zoning Code (chapter as) Medium relevance
Los Altos Hills Zoning Code (§ 10-1.1007) Medium relevance
Los Altos Hills Zoning Code (§ 10-1.1507.) Medium relevance
Los Altos Hills Zoning Code (§ 15) Medium relevance
Los Altos Hills Zoning Code (§ 10-2.1310.) Medium relevance

Cited sections

Official Los Altos Hills code library

Frequently asked questions

What happens to an SB 9 lot‑split application if the property is in a Los Altos Hills historic district?

If the property is located within an historic district or is listed as a Town or Santa Clara County landmark (or included on the State Historic Resources Inventory), it is ineligible for an SB 9 lot split under the Town code; the SB 9 eligibility exception is codified at § 10-1.1503(c).

Do ADUs on historic‑district parcels need parking in Los Altos Hills?

The code provides a parking exemption for accessory dwelling units when the unit is located within “an architecturally and historically significant historic district”; that parking exemption is in § 10-1.1403(g)(2)(iii). Confirm whether the parcel is in a district the Town recognizes as such.

Will the History Committee review my remodel on a historic property?

Site development and certain new‑residence projects are routed to committees for review; the Town’s fast‑track and referral rules specifically provide for referral and participation by the History Committee in site development hearings. See § 10-2.1305.1(b) for the referral and participation framework.

Can I exceed height limits on a historic building to preserve its character?

The nonconforming-structure provisions note that the Planning Commission may permit building height in excess of the usual limit if the increased height is appropriate due to the historic nature of the structure; review § 10-1.401 for the nonconforming rules and the Planning Commission’s discretionary role. Prepare documentation showing the historic basis for the request.

Are historic sites exempt from the Town’s Water Efficient Landscape (WELO) rules?

Registered local, State or Federal historical sites may be exempt from WELO where the landscaping establishes a historic landscape style; see § 10-2.809(a)(1) for the WELO application/exemption language. Confirm site registration and scope with staff.

Which permit rules apply first — a zoning permit or a site development permit — for work on a historic parcel?

Zoning permits are required for the uses listed in § 10-1.310; site development permit thresholds and whether the project is ministerial or discretionary are defined in § 10-2.301. Historic status does not eliminate permit triggers — it usually affects eligibility (e.g., SB 9) or referral/review.

Where do I find the Town’s list or map of historic districts and landmarks?

The Title 10 excerpts we reviewed reference parcels “located within an historic district” or “designated as a Town of Los Altos Hills or Santa Clara County landmark,” but a definitive list/map was not found in the retrieved Title 10 materials. Request the Town’s official map/list and confirmation of a parcel’s status from the Planning Department. (Not found in retrieved materials.)

If my property is historic, can I still apply for an ADU?

Yes — historic designation does not prohibit ADUs; it may change specific requirements (for example, a parking exemption for ADUs in a historic district). ADU standards (design, parking, ministerial approval rules) are in § 10-1.1403–§ 10-1.1404.

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