Local zoning · Santa Clara County

Santa Clara County — Design Review

Design Review under the Santa Clara County local zoning and planning code, with the controlling citations.

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Last reviewed: July 6, 2026

Overview

In unincorporated Santa Clara County, “Design Review” is a discretionary zoning process used to manage visual and neighborhood impacts of development in sensitive areas, administered under the County Zoning Ordinance’s Design Review provisions. It is required in specific combining/overlay districts and in other situations called out by the code, with the Zoning Administrator as the default decision-maker and appeals to the Planning Commission and Board of Supervisors. See the County’s broader zoning & planning overview and the structure of the Zoning Ordinance for context.

Plain-English rule of thumb: If your unincorporated property carries a -d, -h, or is within 100 feet of a designated scenic road, you almost certainly need Design Review before building or expanding.

What “Design Review” means in the County code

  • Purpose and triggers. Design Review exists “to encourage quality design and to mitigate potential adverse visual impacts,” and is required in any “-d” Design Review combining district, any “-h” Historic Preservation combining district, within 100 feet of a designated scenic road on “-sr” lots, when imposed as a condition to address visual impacts (e.g., CEQA mitigation), or when the Zoning Ordinance mandates it for a particular land use.
  • Authority and appeals. The default approval authority is the Zoning Administrator (ZA); appeals go to the Planning Commission (PC) and then the Board of Supervisors (BS) per Table 5.10-1. Note the special Tier 3 rule under the -d1 district (below), where the PC is the initial decision-maker.
  • Scope. Reviews consider visual mitigation, environmental and neighborhood compatibility, adherence to adopted Design Review Guidelines, district regulations, and the General Plan or any applicable specific/area plan.
  • Relationship to other approvals. Some proposals require [Architecture and Site Approval (ASA)] under a different chapter (e.g., many non-residential or multifamily uses); ASA has its own findings and process. Design Review and ASA can both apply depending on use and location.

Countywide Design Review exemptions and administrative approvals

  • Categorical exemptions. The code exempts minor projects from Design Review Countywide (unless superseded by -d1/-sr/-h rules). Examples: additions up to 1,000 sq ft, detached accessory structures up to 1,000 sq ft, accessory dwelling units (ADUs), low decks, certain fences and retaining walls without a grading permit, small antennas, and specified small tanks. Urban Primary Units and certain 800-sq-ft residences on urban lot-split parcels are also exempt.
  • Administrative approvals and discretionary exemptions. The ZA may grant administrative Design Review or discretionary exemptions for modestly larger work (e.g., 1,001–2,000 sq ft additions or detached structures, large decks, certain fences in -d or along scenic roads), and some Tier 1 “Sites Not Visible” cases in the -d1 district. These are without a public hearing unless another section requires one.
  • Fences. In both urban and rural settings, fences that must exceed standard height limits (e.g., tennis court enclosures), or fences in “-d” and “-sr” districts, are channeled to Design Review.

For broader standards you will still need to meet (setbacks, heights, lot coverage), see the County’s Development Standards and project-specific Parking requirements. ADUs follow state preemption—see California ADU law—and remain a Design Review exemption in most cases.

District-by-District: Where Design Review applies and what it looks for

The Design Review provisions are applied through combining/overlay districts that supersede base-zone rules where they conflict; always confirm applied overlays via the parcel’s zoning map and the Ordinance text.

-d 1 Santa Clara Valley Viewshed (Design Review Combining District)

  • Purpose and area. Protects highly visible hillsides seen from the valley floor; uses tiers to scale review to building size.
  • Typical permitted uses. Base zoning uses continue to apply; this district adds visibility-driven siting and design constraints.
  • Process and thresholds.
    • Tier 1: ≤5,000 sq ft GFA. Administrative Design Review (no hearing) unless large retaining walls or exceptions are proposed; color (LRV) standards apply. “Sites Not Visible” can further simplify review.
    • Tier 2: 5,001–12,500 sq ft GFA. Full Design Review; siting must leverage topography/vegetation to mitigate views.
    • Tier 3: >12,500 sq ft GFA. Full Design Review with the Planning Commission as the approving authority; story poles required.
  • Key standards (select).
    • Color: Exterior surfaces limited to a maximum light reflectivity value (LRV) of 45; chroma may be further subdued on high-visibility sites.
    • Massing: Facade and wall-plane limits (e.g., continuous wall length ≤80 ft; typical wall-plane height ≤24 ft, with defined offsets).
    • Retaining walls: Visible walls ≤10 ft; stepped walls must be offset ≥6 ft; color/texture to blend with background.
    • Story poles: Required for Tier 3 at least seven days before hearings (and remain up through hearing close).
  • Where it applies. On mapped -d1 hillsides visible from the valley floor; verify the parcel’s overlay on the County zoning map.

-d 2 Milpitas Hillsides (Design Review Combining District)

  • Purpose and area. Maintains the predominantly natural appearance of the Milpitas hillside areas covered by -d2.
  • Typical permitted uses. Base zoning uses remain, but with strong visual-integration standards; commercial-scale solar is prohibited here.
  • Key dimensional and visual standards.
    • Maximum house size: 6,000 sq ft (lots <10 acres); 8,000 sq ft (≥10 acres).
    • Height: Dwellings max 27 ft and two stories; accessory structures ≤27 ft.
    • Color: LRV ≤45; chroma may be required to be subdued on high-visibility sites.
    • Crestline protection: No structures may “break” the perceived crestline (referenced to the Milpitas crestline mapping); story poles/line-of-sight analyses may be required.
    • Story poles: Required for all new buildings subject to a Design Review hearing (erect ≥7 days before hearing).
  • Where it applies. On parcels mapped with the -d2 overlay in the Milpitas Hillsides area; verify via the County zoning map.

-sr Scenic Roads (Combining District)

  • Purpose and area. Protects the visual character along designated scenic roadways throughout unincorporated areas.
  • Trigger. Any building or structure (including signs) within 100 ft of the scenic road right-of-way requires Design Review. Buildings beyond 100 ft in -sr generally do not, unless another overlay/base rule requires it.
  • Notable limits and exceptions.
    • No DR exemptions for buildings within 100 ft of scenic roads, with limited exceptions for additions not moving closer; certain non-building structures may still be exempt if they meet Chapter 5.50 criteria.
    • Special US 101 rule: No buildings/structures (signs included) within 100 ft of US 101; only fences are potentially allowed, subject to Design Review.
    • Signs: One on-site advertising sign plus one sale/lease sign allowed; special exceptions for agricultural sales/wineries and seasonal signs. See Signage summary.
  • Where it applies. On parcels designated with the -sr overlay along mapped scenic roads.

-h Historic Preservation (Combining Districts)

  • Purpose and area. Preserves historic sites/structures and areas of heritage value. Each -h district may carry its own standards that supersede base zones.
  • Trigger. Design Review is required for:
    • Any new building/structure; and
    • Any exterior modification affecting appearance, unless covered by specific -h exemptions (below).
  • Exemptions within -h (supersede general exemptions):
    • For properties not individually designated: categorical exemptions (e.g., very small accessory structures, low decks/fences, certain paving/retaining walls, PV) and limited discretionary exemptions (e.g., ≤500 sq ft additions or small accessory buildings) at the ZA’s discretion.
    • For properties that are individually designated: categorical exemptions for the same truly minor items, but no discretionary exemptions.
  • Referral. Non-administrative Design Review or ASA in -h is referred to the County Historical Heritage Commission for recommendation before the hearing.
  • Related approvals. Some uses in -h require Architecture and Site Approval as specified in the district; ASA has its own findings.

Cross-cutting rules often seen in Design Review

  • Fences in -d or along scenic roads, and any fence that must exceed standard height limits, commonly go to Design Review.
  • Commercial solar energy conversion systems are not allowed in -d1 or -d2 areas.
  • Countywide Design Review scope emphasizes conformance with adopted Design Review Guidelines; applicants should plan for site-sensitive siting, subdued colors, broken-up massing, and landscaping integration. See Overlay Districts and Landscaping and Screening for related considerations.

Quick reference: When Design Review is required

Scenario in unincorporated areas Is Design Review required? Decision-maker Code Reference
Any development in a “-d” combining district Yes (see district rules below) ZA (Tier 3 in -d1 goes to PC) § 5.50.020; § 3.20.030; -d1 Tier 3 PC rule
Any new/exterior change in a “-h” combining district Yes, unless exempt under -h rules ZA § 3.50.030; § 5.50.020
Within 100 ft of a designated scenic roadway on a “-sr” lot Yes (no building exemptions within 100 ft) ZA § 3.30.030(A)–(B)
US 101 corridor (within 100 ft) Buildings prohibited; fences may be allowed with DR ZA § 3.30.030(C)
ADU anywhere Generally exempt from DR — § 5.50.050(C); § 5.50.060(C). Also see California ADU law
Minor additions/structures (Countywide) Often exempt or administratively approvable ZA § 5.50.050; § 5.50.060

Checklist

  • Confirm your parcel’s applied overlays (-d1/-d2, -sr, -h) and base district on the zoning map; then read the overlay chapter that supersedes the base where conflicts exist.
  • Identify Design Review trigger(s): overlay presence, within 100 ft of a scenic road, or use-specific triggers mandated elsewhere in the code.
  • Classify project size for -d1 (Tier 1/2/3) and whether it qualifies as a “Site Not Visible.”
  • Prepare submittals to show conformance with massing, color (LRV ≤45), siting, retaining wall limits, and any crestline protection that applies.
  • Determine whether your scope is exempt or eligible for administrative Design Review; if not, plan for a noticed public hearing.
  • If in -h, confirm any special -h provisions and the Historical Heritage Commission referral; coordinate with Historic Preservation.
  • If near a scenic road, measure the 100‑ft right-of-way buffer, check US 101’s special setback, and review Signage limits if proposing signs.
  • Cross-check general Development Standards and Parking submittals; Design Review does not replace these.
  • Keep code scopes distinct: Design Review is zoning; building safety remains under the California Building Standards Code.

Risks & Ambiguities

Issue Why it matters What to verify
“Site Not Visible” in -d1 Determines whether administrative approval is possible Work with staff on sightline analyses; the ZA decides per § 3.20.040 references to subsection G.
Scenic road 100‑ft measurement Mis-measurement can misclassify DR applicability or run afoul of US 101’s no‑build buffer Survey right-of-way; confirm with staff for -sr per § 3.30.030.
Crestline in -d2 Structures cannot protrude above perceived crestline Expect story poles/line-of-sight studies; see § 3.20.050(D).
Who decides? ZA vs PC Tier 3 in -d1 goes to the Planning Commission Confirm Tier correctly; see § 3.20.040(A)(3).
Fence exceptions Over-height or scenic-location fences can require DR Height, openness, and location drive whether DR is needed; see § 4.20.050 and § 5.50.060(E).
ADU status ADUs are generally exempt from DR Verify ADU scope; cite § 5.50.050(C). State preemption still applies.

Plain-English Summary

In unincorporated Santa Clara County, Design Review is a focused zoning check on how your project looks and fits its setting—especially on scenic hillsides, near scenic roads, or on historic properties. Expect to show low-reflectivity colors, broken-up massing, and sensitive siting; bigger homes and hillside work may need story poles. Small projects and ADUs often skip Design Review entirely, but overlays like -d1/-d2/-sr/-h can change that.

Source References

  • § 5.50.010–5.50.040 (Design Review purpose, applicability, authority, scope)
  • § 5.50.050 (Countywide Design Review exemptions)
  • § 5.50.060 (Administrative approvals and discretionary exemptions)
  • § 5.10.020 Table 5.10‑1 (Decision/appeal bodies) and Ch. 5.30 (Appeals)
  • § 3.20.020–.040 (Design Review combining districts; -d1 tiers and standards)
  • § 3.20.050 (Milpitas Hillsides -d2 standards: size, height, color, crestline, story poles)
  • § 3.30.010–.040 (-sr Scenic Roads: 100‑ft buffer, exemptions, US 101, signs)
  • § 3.50.010–.040 (-h Historic Preservation: DR triggers, exemptions, HHC referral)
  • § 4.20.050 (Fences; DR triggers)
  • § 4.10.345(B) (Commercial solar prohibited in -d1/-d2)

Sources

Retrieved passages

  • Santa Clara County Zoning Code (§ 30) High relevance
  • Santa Clara County Zoning Code (§ 4.20.020) Medium relevance
  • Santa Clara County Zoning Code (CHAPTER 5.40.) Medium relevance
  • Santa Clara County Zoning Code (Article is) Medium relevance
  • Santa Clara County Zoning Code (title block.) Medium relevance
  • Santa Clara County Zoning Code (§ 3) Medium relevance
  • Santa Clara County Zoning Code (§ 4) Medium relevance
  • Santa Clara County Zoning Code (§ 4) Medium relevance
  • Santa Clara County Zoning Code (Chapter 5.45) High relevance
  • Santa Clara County Zoning Code (§ 3.50.030.) High relevance
  • Santa Clara County Zoning Code (Section C12-5.20) Medium relevance
  • Santa Clara County Zoning Code (Chapter 5.45) Medium relevance
  • Santa Clara County Zoning Code (Article 5) Medium relevance
  • Santa Clara County Zoning Code (§ 1.30.030) Medium relevance
  • Santa Clara County Zoning Code (§ 5.50.050.) Medium relevance
  • Santa Clara County Zoning Code (§ 3.20.020.) Medium relevance
  • Santa Clara County Zoning Code (§ 6) Medium relevance
  • Santa Clara County Zoning Code (§ 4.10.387) Medium relevance

Cited sections

Frequently asked questions

Do I need Design Review for a new house on a hillside in unincorporated areas?

Yes if your lot has a -d1 or -d2 overlay, or is within 100 ft of a designated scenic road. In -d1, your building size tier (≤5,000; 5,001–12,500; >12,500 sq ft) controls whether review is administrative or a full hearing. In -d2, new houses and major exterior changes go through Design Review with specific massing/color limits. See § 5.50.020, § 3.20.030, § 3.20.040, and § 3.20.050.

What if my project is small—can I skip Design Review?

Often. Additions up to 1,000 sq ft, small accessory buildings, and ADUs are exempt Countywide unless a superseding overlay rule applies. The ZA can also grant administrative approvals for 1,001–2,000 sq ft additions/structures and some fences along scenic roads. See § 5.50.050 and § 5.50.060.

How does the scenic roads (-sr) rule work?

If any structure (including a sign) is within 100 ft of a designated scenic road right-of-way, Design Review is required; buildings in this zone don’t qualify for general DR exemptions. Along US 101, no buildings/structures are allowed within 100 ft—only fences may be permitted with DR. See § 3.30.030(A)–(C).

Who approves my Design Review—and can I appeal?

The Zoning Administrator is the default decision-maker; appeals go to the Planning Commission, then the Board of Supervisors. In -d1, Tier 3 projects are decided by the Planning Commission initially. See § 5.10.020 (Table 5.10‑1), § 5.30.010–.070, and § 3.20.040(A)(3).

Are ADUs subject to Design Review?

Generally no—ADUs are listed as Design Review-exempt Countywide, and may also qualify for administrative approvals if part of a larger project. State ADU law still governs setbacks, heights, and other conditions. See § 5.50.050(C) and § 5.50.060(C).

What are the “color” and “massing” rules I keep hearing about in hillside areas?

In -d1 and -d2 areas, exterior colors must be subdued (LRV ≤45), and buildings must break up large wall planes; retaining walls have height/offset limits to soften visual impact. Story poles and sightlines may be required to prove compliance. See § 3.20.040 (LRV/massing/retaining walls) and § 3.20.050 (LRV, crestline, story poles).

Do historic properties always require a hearing?

Most new work or exterior changes in -h do need Design Review; limited minor work is exempt, and non-administrative cases are referred to the Historical Heritage Commission before the hearing. Some uses may also require ASA. See § 3.50.030 and § 3.50.040; ASA applicability is in § 5.40.020(E).

I want a tall fence or tennis court enclosure—does that trigger Design Review?

Often yes. Over-height and certain scenic-location fences require Design Review; “open” fences and standard-height fences may be exempt. See § 4.20.050 and § 5.50.060(E).

Is commercial solar allowed in hillside Design Review districts?

No. Commercial solar energy conversion systems are prohibited in the -d1 and -d2 Design Review districts. See § 4.10.345(B).

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