Local zoning · Contra Costa County

Contra Costa County — Design Review

Q: Is there a ministerial (no-hearing) path anywhere?

Yes. In HE‑C , a multi-family project with at least 20% of units for lower-income households, meeting all mapped density and development standards, is approved ministerially (§ 84-92.806(b)) .

Q: What “architectural” standards might be applied?

Examples include inter-building separation ( 20 ft in M‑29 ), landscaped open areas ( 25% with 75% planted), sign limits (e.g., one 35 sf sign in A‑O ), and setbacks (e.g., 75 ft to a public road in A‑O ) (§ 84-26.1602; § 84-26.1402; § 84-46.1402; § 84-46.1004) .

Q: Do hillside lots have special design review?

Yes. In SDHD‑1 , a development plan and hearing are required; however, a single-family home may be exempt where the lot is legal, the average slope is ≤30%, and there are no significant ridgelines or hilltops (§ 814-2.1402; § 814-2.1408) .

Design Review under the Contra Costa County local zoning and planning code, with the controlling citations.

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Last reviewed: July 6, 2026

Overview

In unincorporated areas of Contra Costa County, “design review” is embedded in the zoning ordinance as development plan approval, site plan and elevations review, and design-control combining overlays. It is not a single, standalone chapter; instead, it appears as required review steps in specific base districts and overlays, commonly with a public hearing under the County’s land use permit procedures. These reviews focus on site planning, architecture, compatibility with surroundings, and conformance to adopted plans and district purposes, and they apply only in the unincorporated areas governed by Divisions 82 and 84 of the County Ordinance Code (§ 82-2.004, unincorporated applicability ).

In Contra Costa County’s unincorporated areas, if your base zoning or an overlay calls for a development plan or “site plan and elevations” review, you’re in design review—even if the ordinance doesn’t label it that way (§ 84-26.1802; § 84-48.404; § 84-70.006; § 84-92.806 ).

Before you dive in, orient yourself with the County’s zoning, land use, and development standards. Related topics—like parking, overlay districts, signage, landscaping and screening, variances and exceptions, and historic preservation—can also interact with design review.

What Counts as “Design Review” Here

Development plan approval in districts that require it (A-O, M-29, N-B, HE-C, SDHD-1) (§ 84-46.1603; § 84-26.1802; § 84-50.1602; § 84-92.802; § 814-2.1402 ).
“Site plan and elevations review” in the Interchange Transitional district (§ 84-48.404 ).
Project conformance review in the —B Design Control Combining District (design-control overlay) (§ 84-70.002; § 84-70.004; § 84-70.006; § 84-70.008 ).

All of these are processed under the County’s land use permit hearing procedures in Chapter 26-2, with findings of compatibility and consistency with the applicable district purpose (§ 84-26.1806; § 84-46.1607; § 84-50.1606; § 84-92.806(a)(1)-(2) ).

When Is Design Review Required? (Quick Map)

Trigger	Where it applies (unincorporated areas)	Decision body	Required findings (abbrev.)	Code Reference
Development plan approval	A-O district	Zoning Administrator (public hearing)	Consistent with district purpose; compatible with nearby uses	§ 84-46.1603, § 84-46.1607
Development plan approval	M-29 district	Zoning Administrator (public hearing)	Consistent with district purpose; compatible with nearby uses	§ 84-26.1802, § 84-26.1806, § 84-26.1808
Development plan approval	N-B district	Zoning Administrator (public hearing)	Consistent with district purpose; architecturally compatible with vicinity	§ 84-50.1602, § 84-50.1606
Site plan & elevations review	Interchange Transitional district	Zoning Administrator	Uses listed are subject to site plan and elevations review	§ 84-48.404
Design-control plan conformance	—B Design Control Combining District (overlay)	Planning Director (may hold hearing)	Consistent with adopted design-control plan and compatible with vicinity	§ 84-70.002, § 84-70.006, § 84-70.008
Development plan approval (with a ministerial path for qualifying projects)	HE-C Housing Element–Conforming district	Planning agency division (hearing), or ministerial if 20% lower-income and standards met	Consistency with district purpose and standards; or ministerial approval per Gov. Code 65583.2(h) if criteria met	§ 84-92.802, § 84-92.806(a)-(b)
Development plan approval (hillside)	SDHD-1 district	Zoning Administrator; exception for one SFD on lots ≤30% avg slope/no significant ridgelines	Consistency and compatibility; processed per Ch. 26-2	§ 814-2.1402, § 814-2.1406, § 814-2.1408

Countywide Development Plan Submittal — What to Show

Most districts requiring a development plan ask for the same core graphics and data:

Topography and a boundary survey; all existing and proposed structures with heights and dwelling unit counts where applicable; planting/landscape areas; parking layout; vehicular and pedestrian ways with grades/widths; site access points; existing and proposed utilities; any recreation facilities; surface drainage; and building elevations indicating architectural type; plus any additional information the review authority requires (§ 84-26.1804; § 84-50.1604; § 84-46.1605; § 84-92.804 ).

District-by-District Design Review Details (Unincorporated Areas)

A-O district

Purpose and applicability: Development proposals must undergo design-focused development plan approval before any “development is lawful” (§ 84-46.1603 ).
Submittals and process: Provide the full development plan package; Zoning Administrator reviews/decides in a public hearing, with possible conditions; changes require further approval (§ 84-46.1605; § 84-46.1607(a)-(d) ).
Key dimensional/design standards often checked in review:
- Minimum rear yard: 50 ft (§ 84-46.1003 ).
- Setback from public road boundary: 75 ft (§ 84-46.1004 ).
- Off-street parking: 1 space per 200 sf of floor area (§ 84-46.1202 ).
- Signs: One sign, max 35 sf, not exceeding roof eave or 20 ft height (§ 84-46.1402 ).
- Open area: At least 25% of lot area landscaped; 75% of that planted (§ 84-46.1702 ).
Variance path: Variances from listed A‑O standards via Chapter 26‑2 (§ 84-46.1802 ).

M-29 district

Purpose and applicability: Multi-family zoning that requires a development plan before development can proceed (§ 84-26.1802 ).
Process and findings: Zoning Administrator hearing; must be consistent with district purpose and compatible; combined hearing allowed if paired with rezoning (§ 84-26.1806; § 84-26.1808 ).
Design-relevant standards:
- Building-to-building separation: 20 ft minimum (§ 84-26.1602 ).
- Open area landscaping: At least 25% landscaped, with 75% of that planted (§ 84-26.1402 ).
- Stall size/coverage: Spaces 9 ft × 19 ft; half of required spaces covered (§ 84-26.[parking standard]—dimensions cited in Article 84‑26; see snippet) (§ 84-26.1602 note and parking dimensional standard in Article 84‑26 ). Not found in retrieved materials: the exact article number heading for the 9'×19' standard in M‑29; verify with the jurisdiction.
Where it applies: As mapped on the County zoning map for unincorporated areas. Verify parcel zoning.

N-B district

Applicability: Requires a development plan for any development activity (§ 84-50.1602 ).
Architectural finding: Approval requires a specific finding that the proposal is “architecturally compatible” with other uses in the vicinity, along with purpose/compatibility findings (§ 84-50.1606(b) ).
Submittals/process: Standard development plan package; Zoning Administrator hearing and conditions possible (§ 84-50.1604; § 84-50.1606(a)-(d) ).
Where it applies: As mapped; typically neighborhood-scale commercial nodes. Not found in retrieved materials: a complete permitted use list for N‑B.

HE-C Housing Element–Conforming district

Applicability: Development plan required, with an optional ministerial path if the project is multi-family, has at least 20% lower-income units, and meets mapped density and all district development standards (§ 84-92.802; § 84-92.806(b) ).
Process: Public hearing for discretionary reviews under Article 26‑2.22; approval must find purpose/compatibility; changes follow a similar process; appeals allowed (§ 84-92.806(a) ).
Where it applies: On designated Housing Element–conforming sites with parcel-specific densities and standards (§ 84-92.806(b)(3) referencing § 84-92.602 and § 84-92.604 ).

Interchange Transitional district

Intent: Tailored for parcels at highway interchanges to achieve exceptional design and minimize detrimental land-use relationships (§ 84-48.204 ).
Design review trigger: Many uses require “site plan and elevations” review by the Zoning Administrator (§ 84-48.404 ).
Where it applies: Only within the area of highway interchanges and their approaches (§ 84-48.204 ).

—B Design Control Combining District (overlay)

Purpose and format: A design-control overlay adopted with an accompanying plan (maps, illustrations, text) governing size, bulk, coverage, color, texture, materials, buildings, signs, and fences. Once adopted, “this plan and accompanying text shall become part of the county code and all further development shall be subject to it” (§ 84-70.004(b) ).
Review authority: Planning Director reviews and approves development or alterations for conformance; may hold a public hearing; may impose conditions; appeals per Chapter 26‑2 (§ 84-70.006(a)-(d) ).
Review criteria: Considers the plan’s objectives and local compatibility (§ 84-70.008 ).

SDHD-1 district

Applicability: Requires development plan approval; Zoning Administrator hearing under Chapter 26‑2 (§ 814-2.1402; § 814-2.1406(a)-(d) ).
Exception: A single detached dwelling may be allowed ministerially if the lot is a legal lot, average slope is ≤30%, and no significant ridgelines/hilltops are present (§ 814-2.1408 ).
Submittals: Similar to other development plan districts, including elevations with architectural type (§ 814-2.1404(11) ).

Design-Related Dimensional Standards Often Reviewed

The A‑O district’s design review frequently checks setbacks, signage, landscaping, and parking: rear yard 50 ft (§ 84-46.1003), setback from public road 75 ft (§ 84-46.1004), one sign max 35 sf and height limits (§ 84-46.1402), open area 25% landscaped with 75% planted (§ 84-46.1702), and 1 parking space per 200 sf floor area (§ 84-46.1202) .
In M‑29, common design checks include inter-building separation 20 ft (§ 84-26.1602), open area 25% landscaped with 75% planted (§ 84-26.1402), and typical multi-family stall sizes 9×19 ft with 50% covered (Article 84‑26 parking standard—verify exact section number) (§ 84-26.1402; 84‑26 [parking standard excerpt] ).

For broader standards by zone, see Development Standards. For signs outside A‑O or project-specific sign programs, see Signage. If a deviation from a standard is needed, consult Variances and Exceptions.

Checklist

Confirm your property is in the unincorporated area and identify base zoning and any overlays (Zoning; § 82-2.004) .
Determine whether a development plan or site plan/elevations review is required by your district (e.g., A‑O, M‑29, N‑B, HE‑C, SDHD‑1, Interchange Transitional, —B overlay) (§§ cited above).
Prepare a complete development plan submittal with required graphics/elevations and narratives (§ 84-26.1804; § 84-50.1604; § 84-46.1605; § 84-92.804) .
Demonstrate compatibility with surrounding uses and consistency with district purposes (typical findings; see § 84-26.1806; § 84-50.1606; § 84-46.1607; § 84-92.806(a)(2)) .
Check dimensional and design standards that are commonly conditioned in approvals (e.g., setbacks, parking, landscaping, signage).
If in the —B overlay, align materials, colors, and details with the adopted design-control plan (§ 84-70.004, § 84-70.006) .
For HE‑C projects, check if you qualify for ministerial approval (≥20% lower-income units and full compliance with mapped density/standards) (§ 84-92.806(b)) .
If a standard cannot be met, evaluate whether a variance path exists for your district (e.g., § 84-46.1802; § 84-92.1002) .
Keep nonconformities in mind—expansions or exterior changes can trigger additional review; see Nonconforming Uses.
Building code compliance is separate; see the California Building Standards Code page. State housing mandates may also affect process; see California housing laws and California ADU law.

Risks & Ambiguities

Issue	Why it matters	What to verify
Exact parking stall section for M‑29	The 9×19 ft, 50% covered standard is excerpted from Article 84‑26; exact subsection header not shown in retrieved text	Confirm the precise section number with the County (§ 84‑26 [parking excerpt])
Whether your use triggers site plan/elevations in Interchange Transitional	Only listed uses are subject to this review	Check your specific use against § 84‑48.404
What “architecturally compatible” means in N‑B	It is an explicit approval finding	Discuss precedent and submittal expectations with staff; base finding is in § 84‑50.1606(b)
Applicability of —B overlay criteria	Each —B district has its own adopted plan with binding details	Obtain the adopted plan text/maps for your —B overlay (§ 84‑70.004)
Ministerial path in HE‑C	Can avoid hearing if criteria met	Confirm parcel-specific density (§ 84‑92.602) and full compliance with § 84‑92.604 via § 84‑92.806(b)
A‑O permitted uses	Design review scope depends on the underlying use mix	Not found in retrieved materials—request A‑O use table from the County

Plain-English Summary

In unincorporated Contra Costa County, “design review” happens when your zoning district or overlay says you need a development plan or a site plan/elevations review. That triggers a County look at your site layout, architecture, access, parking, landscaping, and how your project fits the neighborhood. Some districts (like N‑B) even require an explicit architectural compatibility finding, and certain overlays (—B) lock in a detailed design palette. If you’re on a Housing Element site (HE‑C) and meet affordability and standards, you might even qualify for ministerial approval.

Source References

Unincorporated applicability: § 82-2.004 (Divisions 82 and 84 apply in unincorporated county)
A‑O district: § 84-46.1003 (rear yard); § 84-46.1004 (setback from public road); § 84-46.1202 (parking); § 84-46.1402 (signs); § 84-46.1603 (development plan required); § 84-46.1605 (submittals); § 84-46.1607 (process/findings); § 84-46.1702 (open area); § 84-46.1802 (variances)
M‑29 district: § 84-26.1402 (open area); § 84-26.1602 (building separation); § 84-26.1802 (development plan required); § 84-26.1804 (submittals); § 84-26.1806 (process/findings); § 84-26.1808 (rezoning coordination)
N‑B district: § 84-50.1602 (development plan required); § 84-50.1604 (submittals); § 84-50.1606 (process and “architecturally compatible” finding)
Interchange Transitional district: § 84-48.204 (purpose); § 84-48.404 (site plan and elevations review)
—B Design Control Combining District (overlay): § 84-70.002 (general); § 84-70.004 (purpose/plan content); § 84-70.006 (Planning Director approval); § 84-70.008 (review criteria)
HE‑C district: § 84-92.802 (development plan required); § 84-92.804 (submittals); § 84-92.806(a)-(b) (process; ministerial path); § 84-92.1002 (land use/variance permits)
SDHD‑1 district: § 814-2.1402 (development plan required); § 814-2.1404 (submittals); § 814-2.1406 (process); § 814-2.1408 (single-family exception)
Countywide note: Many review procedures reference Chapter 26‑2 hearings and findings (see code sections above).

Sources

Retrieved passages

Contra Costa County Zoning Code (§ 6) Medium relevance
Contra Costa County Zoning Code (Article 814-2.14.) Medium relevance
Contra Costa County Zoning Code (§ 2) Medium relevance
Contra Costa County Zoning Code (§ 2) Medium relevance
Contra Costa County Zoning Code (Chapter 26-2.) Medium relevance
Contra Costa County Zoning Code (§ II) Medium relevance
Contra Costa County Zoning Code (§ 1) Medium relevance
Contra Costa County Zoning Code (§ 4) Medium relevance

Cited sections

Official Contra Costa County code library

Frequently asked questions

Do I need design review in unincorporated Contra Costa County?

Yes, if your base zoning or an overlay requires a development plan or a site plan/elevations review. Common triggers include the A‑O, M‑29, N‑B, HE‑C, and SDHD‑1 districts, the Interchange Transitional district, and the —B design-control overlay (§ 84-46.1603; § 84-26.1802; § 84-50.1602; § 84-92.802; § 814-2.1402; § 84-48.404; § 84-70.006) .

What does a development plan have to include?

Expect detailed site plans, elevations showing architectural type, topography, access, parking, utilities, landscaping, and drainage. The ordinance lists these items in multiple districts (§ 84-26.1804; § 84-50.1604; § 84-46.1605; § 84-92.804) .

What are the approval findings for design review?

Approvals generally require findings of consistency with the district’s purpose and compatibility with surrounding uses; N‑B adds an “architecturally compatible” finding (§ 84-26.1806; § 84-46.1607; § 84-50.1606; § 84-92.806(a)(2)) .

Is there a ministerial (no-hearing) path anywhere?

Yes. In HE‑C, a multi-family project with at least 20% of units for lower-income households, meeting all mapped density and development standards, is approved ministerially (§ 84-92.806(b)) .

What “architectural” standards might be applied?

Examples include inter-building separation (20 ft in M‑29), landscaped open areas (25% with 75% planted), sign limits (e.g., one 35 sf sign in A‑O), and setbacks (e.g., 75 ft to a public road in A‑O) (§ 84-26.1602; § 84-26.1402; § 84-46.1402; § 84-46.1004) .

What if my project is within a —B Design Control Combining District?

Your design must match the adopted plan’s criteria for size, materials, colors, and appurtenances; the Planning Director reviews for conformance and may impose conditions (§ 84-70.004; § 84-70.006) .

Do hillside lots have special design review?

Yes. In SDHD‑1, a development plan and hearing are required; however, a single-family home may be exempt where the lot is legal, the average slope is ≤30%, and there are no significant ridgelines or hilltops (§ 814-2.1402; § 814-2.1408) .

Can I get a variance from a design-related standard?

Possibly. For example, variances may be granted from listed A‑O standards via Chapter 26‑2, and HE‑C references variance permits for its standards (§ 84-46.1802; § 84-92.1002) .

Are ADUs part of design review?

ADU approvals primarily follow state law and a ministerial track; see California ADU law. Not found in retrieved materials: a Contra Costa County–specific ADU design review provision in the cited sections; verify with the jurisdiction.

Does the building code affect design review?

Building code compliance is separate from zoning/design review; see the California Building Standards Code. Design review focuses on zoning, site planning, and architecture; building safety is outside this page’s scope.

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