Contra Costa County — Zoning

Last reviewed: July 6, 2026

Overview

This page distills how Contra Costa County regulates land use through its zoning ordinance for the unincorporated areas only. The County’s adopted “Zoning Map of Contra Costa County” designates each parcel’s zoning district and governs what can be built; where the map is unclear, the ordinance provides boundary rules and interpretation procedures. See the adopted map reference and district framework in § 84-2.002 and § 84-2.004 . Use this guide alongside the Contra Costa County zoning & planning overview and project-specific resources like Development Standards, Parking, and Design Review.

Key rule: Your parcel’s zoning on the “Zoning Map of Contra Costa County” controls allowed uses and development standards. When a boundary is unclear, the County applies centerline/lot-line rules, scale measurements, and, if needed, a Planning Commission determination under § 84-2.002(d) .

How the County’s zoning framework is organized

• The County’s zoning districts live in Division 84 (Land Use Districts). The Zoning Map is adopted by reference; official paper and digital versions are on file with the County, and amendments are reflected on that map under § 84-2.002(a)–(c) .
• Countywide policy overlays constrain where urban zoning may occur. Notably, the voter-adopted Urban Limit Line limits urban designations outside that line; it’s integrated with the County’s open space plan (see § 82-1.010 and related policies) .
• Some special districts and combining districts add rules on top of base zoning. See the overlay summaries below and also visit Overlay Districts.

Reading the Zoning Map (unincorporated areas)

• Map adoption and maintenance: see § 84-2.002(a)–(c); changes are posted to the official map and incorporated into the ordinance .
• Boundary interpretation: center of street rights-of-way, lot lines, scaled distances, and administrative/commission interpretations control under § 84-2.002(d)(1)–(5) .

District-by-District Guide (base districts)

Where it applies: For each district below, application is “where mapped” in the unincorporated areas. Confirm the designation on the County Zoning Map per § 84-2.002 (official map on file). If a specific neighborhood is critical to your project, verify with the jurisdiction.

R-6 — Single-Family Residential

• Purpose and uses: Detached single-family dwellings; small licensed care and child care; publicly owned parks; crop and tree farming; and by-right ADUs/JADUs consistent with Chapter 82-24. Supportive and transitional housing for up to six persons are also allowed. See § 84-4.402 . For ADU rights under state law, also see California ADU law.
• Key standards: Minimum lot area 6,000 sq ft (§ 84-4.602), width 60 ft (§ 84-4.604), depth 90 ft (§ 84-4.606); height max 2.5 stories/35 ft (§ 84-4.802); side yards aggregate 15 ft with 5 ft minimum (accessory buildings may reduce to 3 ft if ≥50 ft from front line) (§ 84-4.1002); front setback 20 ft (corner: 20/15 ft) (§ 84-4.1004); rear yard 15 ft (principal)/3 ft (accessory) (§ 84-4.1006). Off-street parking: at least two spaces per unit (with limited legacy-lot exception) in § 84-4.1202; also see Parking .
• Where it applies: Where mapped; verify on the County Zoning Map (§ 84-2.002) .

R-7 — Single-Family Residential

• Uses: Mirrors R-6 uses (§ 84-6.402, § 84-6.404) .
• Key standards: Minimum lot 7,000 sq ft/70 ft width (§ 84-6.602, § 84-6.604); depth, height, yards, parking all follow R-6 (§§ 84-6.606, 84-6.802, 84-6.1002–1006, 84-6.1202) .

R-10 — Single-Family Residential

• Uses: Mirrors R-6 allowed uses and LUP uses (§ 84-8.402, § 84-8.404) .
• Key standards: Minimum lot 10,000 sq ft/80 ft width (§ 84-8.602, § 84-8.604); height same as R-6; side yards aggregate 20 ft with 10 ft minimum; front setback follows R-6; rear yard follows R-6 (§§ 84-8.606, 84-8.802, 84-8.1002–1006) .

R-12 — Single-Family Residential

• Uses: Mirrors R-6 (§ 84-10.402, § 84-10.404) .
• Key standards: Minimum lot 12,000 sq ft; width 100 ft; depth 100 ft; height same as R-6; side yards aggregate 25 ft with 10 ft minimum; front and rear yards follow R-6 (§§ 84-10.602–1006, 84-10.802) .

R-15 — Single-Family Residential

• Uses: Mirrors R-6 (§ 84-12.402, § 84-12.404) .
• Key standards: Minimum lot 15,000 sq ft; width/depth mirror R-12; height same as R-6; side yards mirror R-12; front and rear yards follow R-6 (§§ 84-12.602–1006, 84-12.802) .

R-20 — Single-Family Residential

• Uses: Single-family; crop/horticulture; seasonal farm stands with acreage/time/location limits; small care/child care; urban farm animal keeping; ADUs/JADUs; supportive/transitional housing (≤6). Some LUP uses mirror R-6 with exceptions; equestrian instruction allowed by LUP. See § 84-14.402 and § 84-14.404 .
• Key standards: Minimum lot 20,000 sq ft/120 ft width/120 ft depth; height same as R-6; side yards aggregate 35 ft with 15 ft min; front setback 25 ft (corner: 25/20 ft); rear yard follows R-6 (§§ 84-14.602–1006, 84-14.802) .

R-40 — Single-Family Residential

• Uses: Mirror R-20 (allowed and LUP) (§ 84-16.402, § 84-16.404) .
• Key standards: Minimum lot 40,000 sq ft/140 ft width/140 ft depth; height same as R-6; side yards aggregate 40 ft with 20 ft minimum; front setback follows R-20; rear yard follows R-6 (§§ 84-16.602–1006, 84-16.802) .

R-65 — Single-Family Residential

• Uses: Mirrors R-20 with some LUP deletions (e.g., greenhouses >300 sq ft; hospitals/convalescent homes removed) and equestrian instruction allowed by LUP. See § 84-18.402, § 84-18.404 .
• Key standards: Minimum lot 65,000 sq ft; width/depth mirror R-40; side yards per R-40; front setback per R-20; rear yard per R-6; height per R-6 (§§ 84-18.602–1006, 84-18.802) .

R-100 — Single-Family Residential

• Uses: Permitted uses mirror R-20; LUP uses mirror R-65 (§ 84-20.402, § 84-20.404) .
• Key standards: Minimum lot 100,000 sq ft/200 ft width/200 ft depth; height same as R-6; side yards aggregate 60 ft with 30 ft minimum; front 30 ft (corner: 30/25 ft); rear 30 ft (principal)/3 ft (accessory) (§§ 84-20.602–1006, 84-20.802) .

D-1 — Two-Family Residential

• Uses: Two-family dwellings, with R-10 side yards and R-6 front and rear setbacks by reference (§§ 84-22.1002–1006). Minimum lot 8,000 sq ft; width mirrors R-10; depth mirrors R-6; height per R-6 (§§ 84-22.602–802) .

M-29 — Multiple-Family Residential (example multi-family district)

• Uses and densities: A multiple-family district allowing up to 29 units/acre; height 30 ft with edge-height step-downs next to single-family; specified 20 ft side and rear yards, 25 ft front setback; off-street parking by unit type (see Article 84-26). See § 84-26.610, § 84-26.802, § 84-26.1002–1008, § 84-26.1202 .

A-20, A-40, A-80 — Exclusive Agricultural

• Purpose: Preserve agricultural lands; prevent incompatible urban uses (§ 84-80.204, § 84-82.204, § 84-84.204) .
• Uses: Broad agriculture; farm stands; one single-family dwelling per legal lot; ADUs/JADUs; farmworker housing/complexes; significant ag-processing and ag-support uses by LUP (see § 84-80.402, § 84-80.404) .
• Key standards: Minimum parcel sizes scale with the district—A-20: 40 ac minimum outside urban areas by policy; A-40: 40 ac; A-80: 80 ac; with some LUP categories limited/removed in A-40/A-80 (see “Differences” in § 84-82.404, § 84-84.404) . Verify mapped lot standards on the Zoning Map (§ 84-2.002) .

F-1 — Forestry Recreation

• Standards: Lot area/width/depth, height, and most yards mirror R-6, with a special 50 ft levee centerline setback where applicable (§ 84-34.602–1008) .

O-1 — Limited Office

• Uses: Professional/admin/business offices by right; broader institutional/civic and limited ancillary retail by LUP (§ 84-44.402–404) .
• Key standards: Front 20 ft (corner: 20/15 ft) and rear yards per R-6; max gross floor area 15,000 sq ft; landscaped open area minimums; parking ratios for offices/medical in § 84-44.1202 (also see Parking) (§§ 84-44.1004–1602) .

C-B — Central Business

• Uses: O-1 uses plus enclosed retail by right; additional retail/animal hospital/housing by LUP (§ 84-49.402–404) .
• Key standards: No front setback; side/rear yards only when abutting residential (10 ft side/15 ft rear); height 35 ft (§§ 84-49.1002–1006, 84-49.802) .

N-B — Neighborhood Business

• Uses: Enclosed neighborhood-serving retail and services (e.g., bakery, grocery, drugstore, barbers, shoe repair), plus professional/real estate offices by right; apartments (3+ units) and gas stations by LUP (§ 84-50.402, § 84-50.404) .
• Key standards: Minimum lot 3,500 sq ft/35 ft width; no side yards; front setback 25 ft from road right-of-way; height max 50 ft (§§ 84-50.602, 84-50.1002–1004, 84-50.802) .

R-B — Retail Business

• Uses: Enclosed retail by right; hotels/motels and residential allowed; heavier service/trades by LUP (§ 84-52.402–404) .
• Key standards: Lot area, height, side-yard zero, and 10 ft front setback largely mirror N-B (§§ 84-52.602–1004, 84-52.802) .

C — General Commercial

• Uses: Broad wholesale, warehouse, yards and trades by right; hotels, motels, multi-unit housing by LUP; emergency shelters per standards; commercial cannabis by LUP (§ 84-54.402–404) .
• Key standards: Minimum lot 7,500 sq ft; side yards aggregate 10 ft; rear yard 20 ft; front 10 ft; height per N-B (§§ 84-54.602, 84-54.1002–1004, 84-54.802) .

L-I — Light Industrial

• Uses: Non-nuisance industrial by right; more intensive or potentially impactful uses require LUP; many commercial/residential district uses may be allowed by LUP (§ 84-58.402–404) .
• Key standards: Minimum lot 7,500 sq ft; side yards 10 ft each; front 10 ft; max height 3 stories (§§ 84-58.602, 84-58.1002–1004, 84-58.802) .

H-I — Heavy Industrial

• Uses: Heavy industrial/manufacturing by right; LUP requirements mirror L‑I’s permit list (§ 84-62.402–404) .
• Key standards: No lot area, height, or side yard limits in the district (project-level controls still apply) (§ 84-62.602) .

W-3 — Controlled Heavy Industrial

• Uses: Broad heavy industry by right; non-industrial uses need LUP; special review within 250 ft of other district boundaries (except H‑I/L‑I/U) (§ 84-60.402–404) .
• Key standards: No dimensional requirements except as triggered by buffer review (§ 84-60.602) .

HE‑C — Housing Element Consistency District

• Purpose: Implements Housing Element sites and parcel-specific densities to meet state law; allows residential at the listed density and certain mixed-use co-location where designated (§ 84-92.202, § 84-92.402) .
• Uses: Residential at parcel-specific densities; certain ground-floor N‑B or R‑B retail where mapped for mixed-use; small care/child care/ADUs/supportive/transitional housing by right (§ 84-92.402) .

Combining and Special Districts (selected)

• Design Control (—B): Imposes plan-based design control; projects subject to Planning Director review and potential conditions; appeals per Chapter 26-2. See § 84-70.002–.008; coordinate early with Design Review .
• Transition (—T): Combines with residential to allow limited studio/office-type uses by LUP; priority rules apply if conflicts arise (§ 84-72.404–.408, § 84-72.602) .
• Kensington (—K): Area-specific residential compatibility standards for views, light/solar, privacy, scale, and parking—applies only where mapped in Kensington (§ 84-74.202–.204) .
• Cannabis Exclusion (—CE): Prohibits commercial cannabis in listed communities (Acalanes Ridge, Alamo, Bethel Island, Blackhawk, Bollinger Canyon, Contra Costa Centre, Knightsen, Sandmound Slough, Saranap) and prevails over underlying zoning where in conflict (§ 84-86.202–.208) .

Cross-cutting standards you’ll use on most projects

• Setbacks catalog: Front/side/rear yard rules live in each district chapter and are cross-referenced by Chapter 82-12 (see footnote and references in § 82-12.202) .
• Height exceptions: Appurtenances (chimneys, antennas, water tanks, etc.) can exceed district height caps per § 82-2.008; parapets up to 3 ft allowed .
• Small-lot occupancy: Pre-existing undersized lots may still be buildable for one single-family dwelling if yard/setback rules are met (discretionary compatibility review possible) per § 82-10.002(c); boundary split lots may borrow up to 30 ft across the line per § 82-10.006 .
• Flood hazard: Development in mapped flood areas must meet the County’s floodplain regulations, including freeboard of 2 ft in the Delta and 1 ft elsewhere in unincorporated areas (§ 82-28.604) .
• Airports: Separate airport zoning provisions apply near Buchanan Field (Title 86-4) and permitting rules for airports/heliports limit where such facilities can be approved (§ 86-2.1002–.1008, § 86-4.002–.006)—verify early for height/safety constraints .
• Signs: Commercial and office districts often defer to Chapter 88-8; see district-specific references (e.g., § 84-49.1402, § 84-44.1802) and visit Signage .
• Nonconforming situations: If your site is nonconforming, see Nonconforming Uses; state housing mandates can also affect outcomes—see California housing laws.

Quick reference table — common single-family districts (unincorporated)

Practical notes when planning

• ADUs/JADUs are allowed in residential and agricultural districts consistent with Chapter 82-24 and state law; density and many local limits don’t block at least an 800 sq ft ADU with 4 ft side/rear setbacks under state rules. See district allowances (e.g., § 84-4.402(7)) and the state summary in the 2025 HCD handbook .
• Many commercial districts permit multi-unit residential by land use permit; confirm Parking and any Design Review triggers referenced by the district article.
• Airport, floodplain, and combining districts can limit height, require added setbacks/freeboard or impose site/design conditions—coordinate early. See § 82-28.604 and Title 86 airport chapters .

Checklist

• Confirm your parcel’s zoning on the County Zoning Map (official map on file) and any combining/overlay districts per § 84-2.002; if a boundary is unclear, apply § 84-2.002(d) .
• Verify allowed uses and whether a land use permit is required in your district (e.g., § 84-4.402, § 84-54.404) .
• Check dimensional standards (lot area/width/depth, height, yards) for your district and any exceptions (e.g., § 82-2.008 height appurtenances) .
• Confirm Parking requirements (e.g., § 84-4.1202) and any district-specific ratios (e.g., § 84-44.1202) .
• Screen for floodplain, airport, and other constraints (e.g., § 82-28.604; Title 86-4) and consult Overlay Districts .
• If the lot is substandard or split by a district boundary, apply small-lot and boundary rules (§§ 82-10.002(c), 82-10.006) and review Nonconforming Uses .
• If a variance is needed, see Variances and Exceptions and the district’s variance clause (e.g., § 84-4.1402) .
• If in a design-controlled or Kensington area, budget time for Design Review (e.g., § 84-70.006) .

Risks & Ambiguities

Plain-English Summary

If your property is in the unincorporated County, start with the official Zoning Map to see the district. That district’s chapter tells you what uses are allowed and the exact lot size, height, and setback rules you must meet; some districts allow small care homes and ADUs by right. Overlays like design control, cannabis exclusion, floodplain, or airport zones can add conditions or limits, so check those early, then confirm parking and whether your project needs design review or any variance.

Source References

• Zoning Map adoption and districts created: § 84-2.002, § 84-2.004
• R-6 uses and standards: §§ 84-4.402, 84-4.602–1006, 84-4.1202
• R-7/R-10/R-12/R-15/R-20/R-40/R-65/R-100 cross-references and standards: §§ 84-6.402–1006; 84-8.402–1006; 84-10.402–1006; 84-12.402–1006; 84-14.402–1006; 84-16.402–1006; 84-18.402–1006; 84-20.402–1006
• D‑1 two-family standards: §§ 84-22.602–1006
• M‑29 multi-family standards: §§ 84-26.610, 84-26.802, 84-26.1002–1202
• Agricultural districts A-20/A-40/A-80: §§ 84-80.202–404; 84-82.402–404; 84-84.202–404
• Forestry Recreation F‑1: §§ 84-34.602–1008
• Office/Commercial districts: O‑1 §§ 84-44.402–.1802; C‑B §§ 84-49.402–.2002; N‑B §§ 84-50.402–.1608; R‑B §§ 84-52.402–.1602; C §§ 84-54.202–.1202
• Industrial districts: L‑I §§ 84-58.402–.1202; H‑I §§ 84-62.202–.602; W‑3 §§ 84-60.202–.602
• HE‑C Housing Element Consistency: §§ 84-92.202–.404
• Combining/Overlays: —B §§ 84-70.002–.008; —T §§ 84-72.404–.604; —K §§ 84-74.202–.204; —CE §§ 84-86.202–.208
• Height exceptions and utilities: § 82-2.008, § 82-2.010
• Small-lot occupancy, district-boundary, setbacks catalog: §§ 82-10.002(c), 82-10.006; 82-12.202
• Floodplain management: § 82-28.604; variances § 82-28.1202
• Airports: §§ 86-2.1002–.1008; 86-4.002–.006

Retrieved passages

• Contra Costa County Zoning Code (Chapter 84-2) High relevance show source text
• Contra Costa County Zoning Code (§ III) High relevance show source text
• Contra Costa County Zoning Code (§ 2) High relevance show source text
• Contra Costa County Zoning Code (§ 3) High relevance show source text
• Contra Costa County Zoning Code (§ VII) High relevance show source text
• Contra Costa County Zoning Code (Chapter 82-46.) High relevance show source text
• Contra Costa County Zoning Code (§ III) High relevance show source text
• Contra Costa County Zoning Code (§ 2) High relevance show source text
• Contra Costa County Zoning Code (§ 8143) High relevance show source text
• Contra Costa County Zoning Code (Article 84-52.6.) High relevance show source text
• Contra Costa County Zoning Code (Section 84-4.602) High relevance show source text
• Contra Costa County Zoning Code (chapter and) High relevance show source text
• Contra Costa County Zoning Code (§ 8157.5) High relevance show source text
• Contra Costa County Zoning Code (Section 84-4.404) High relevance show source text
• Contra Costa County Zoning Code (Section 82-2.008) High relevance show source text
• Contra Costa County Zoning Code (§ 8145) High relevance show source text
• Contra Costa County Zoning Code (§ 8142) High relevance show source text
• Contra Costa County Zoning Code (§ 8148.7) High relevance show source text
• Contra Costa County Zoning Code (§ 8148) High relevance show source text
• Contra Costa County Zoning Code (§ VIII) High relevance show source text
• Contra Costa County Zoning Code (§ 8143) High relevance show source text
• Contra Costa County Zoning Code (§ 8159) High relevance show source text
• Contra Costa County Zoning Code (§ IX) High relevance show source text
• Contra Costa County Zoning Code (§ 2) High relevance show source text
• Contra Costa County Zoning Code (Article 84-50.16.) High relevance show source text
• Contra Costa County Zoning Code (§ 5) Medium relevance show source text
• Contra Costa County Zoning Code (Article 84-58.12.) Medium relevance show source text
• Contra Costa County Zoning Code (§ XVI) Medium relevance show source text
• Contra Costa County Zoning Code (§ 8148) High relevance show source text
• Contra Costa County Zoning Code (§ 8146) High relevance show source text
• Contra Costa County Zoning Code (§ 8148) High relevance show source text
• Contra Costa County Zoning Code (§ 8148.7) Medium relevance show source text
• Contra Costa County Zoning Code (§ 8149) Medium relevance show source text

Cited sections

• Zoning Map adoption and districts created: **§ 84-2.002**, **§ 84-2.004** (§ 84-2.002)
• R-6 uses and standards: **§§ 84-4.402, 84-4.602–1006, 84-4.1202** (§ 84-4.402)
• R-7/R-10/R-12/R-15/R-20/R-40/R-65/R-100 cross-references and standards: **§§ 84-6.402–1006; 84-8.402–1006; 84-10.402–1006; 84-12.402–1006; 84-14.402–1006; 84-16.402–1006; 84-18.402–1006; 84-20.402–1006** (§ 84-6.402)
• D‑1 two-family standards: **§§ 84-22.602–1006** (§ 84-22.602)
• M‑29 multi-family standards: **§§ 84-26.610, 84-26.802, 84-26.1002–1202** (§ 84-26.610)
• Agricultural districts A-20/A-40/A-80: **§§ 84-80.202–404; 84-82.402–404; 84-84.202–404** (§ 84-80.202)
• Forestry Recreation F‑1: **§§ 84-34.602–1008** (§ 84-34.602)
• Office/Commercial districts: O‑1 **§§ 84-44.402–.1802**; C‑B **§§ 84-49.402–.2002**; N‑B **§§ 84-50.402–.1608**; R‑B **§§ 84-52.402–.1602**; C **§§ 84-54.202–.1202** (§ 84-44.402)
• Industrial districts: L‑I **§§ 84-58.402–.1202**; H‑I **§§ 84-62.202–.602**; W‑3 **§§ 84-60.202–.602** (§ 84-58.402)
• HE‑C Housing Element Consistency: **§§ 84-92.202–.404** (§ 84-92.202)
• Combining/Overlays: —B **§§ 84-70.002–.008**; —T **§§ 84-72.404–.604**; —K **§§ 84-74.202–.204**; —CE **§§ 84-86.202–.208** (§ 84-70.002)
• Height exceptions and utilities: **§ 82-2.008**, **§ 82-2.010** (§ 82-2.008)
• Small-lot occupancy, district-boundary, setbacks catalog: **§§ 82-10.002(c), 82-10.006; 82-12.202** (§ 82-10.002)
• Floodplain management: **§ 82-28.604**; variances **§ 82-28.1202** (§ 82-28.604)
• Airports: **§§ 86-2.1002–.1008; 86-4.002–.006** (§ 86-2.1002)
• ContraCostaCounty_ZoningCode.md
• 2025 California ADU handbook.md

• Official Contra Costa County code library