Local zoning · Napa County

Napa County — Development Standards

Development Standards under the Napa County local zoning and planning code, with the controlling citations.

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Last reviewed: July 6, 2026

Overview

In Napa County’s unincorporated areas, development standards live in the zoning ordinance (Title 18) and are largely driven by each base district plus countywide rules for yards, encroachments, and special uses. The single best “one-page” starting point is the county’s Schedule of Zoning District Regulations, which sets minimum lot area, minimum yards (front/side/rear), maximum lot coverage, and height by district. See § 18.104.010 . Beyond the base metrics, special programs—like winery coverage/setbacks and the overlay districts—can tighten what and where you can build.

Most projects in unincorporated Napa County start with the Schedule of Zoning District Regulations; your lot’s district controls the baseline setbacks, height, and coverage (§ 18.104.010 ).

Countywide dimensional matrix (what the table covers)

  • The Schedule lists minimum lot area, lot width, required yards, maximum building coverage, and maximum height for each district (§ 18.104.010 and footnotes C, E, G ; ).
  • “Front/side/rear yard” are defined terms; critically, a yard along a public or private road begins at the outer edge of any required road setback, not at the property line (§ 18.08.650; references Chapter 18.112 road setbacks) .
  • Required yards must remain unobstructed, with limited, enumerated encroachments (eaves, stairs, etc.) (§ 18.104.260 ). Fences are limited to 4 ft in front yards and 8 ft in sides/rear, with “see‑through” above 6 ft unless a fence use permit is granted (§ 18.104.270 ).

District-by-district standards (selected unincorporated districts)

AP — Agricultural Preserve

  • Purpose: Keep fertile valley and foothill lands in agriculture; prevent urban encroachment (§ 18.16.010 ).
  • Typical permitted uses: Agriculture and one single‑family dwelling per legal lot; accessory dwelling units; small residential care/day care; existing/legal wineries, etc. (§ 18.16.020 ).
  • Key dimensional standards: 40 acres minimum lot area; 20 ft front/side/rear yards; 35 ft height (§ 18.104.010 ). On AP parcels ≤2 acres, side yards follow RS side yard standards (§ 18.104.010(B) ).
  • Where it applies: Unincorporated valley and foothill areas mapped AP.

AW — Agricultural Watershed

  • Purpose: Protect watershed, reservoirs, and tributaries; keep uses agriculturally oriented (§ 18.20.010 ).
  • Typical permitted uses: Agriculture and one single‑family dwelling per legal lot; ADUs; small care/day care; certain winery situations with proper approvals (§ 18.20.020 ).
  • Key dimensional standards: 160 acres minimum lot area; 20 ft front/side/rear yards; 35 ft height (§ 18.104.010 ). On AW parcels ≤2 acres, side yards use RS side yard standards (§ 18.104.010(B) ).
  • Where it applies: Hillside/watershed areas outside cities.

RS — Residential Single

  • Purpose: Single‑family neighborhoods in places with urban services; regulate density and building bulk (§ 18.52.010 ).
  • Typical permitted uses: One single‑family dwelling per legal lot; ADUs/JADU; small/large family day care; small/medium residential care; limited school/home instruction (§ 18.52.020 ).
  • Key dimensional standards: 8,000 sf minimum lot size; 60 ft minimum lot width; 20 ft front, 6 ft side (see footnote C for narrow lots), 20 ft rear; 50% maximum main building coverage; 35 ft height (§ 18.104.010 and footnote C ; ). Deep-lot second units require a use permit and must meet spacing/access rules (§ 18.52.040 ).
  • Where it applies: Unincorporated urbanized pockets.

RM — Residential Multiple

  • Purpose: Multifamily housing in areas otherwise suitable for RS, with public water/sewer (§ 18.60.010 ).
  • Typical permitted uses: Multiple‑family and single room occupancy units; ADUs/JADU; supportive and transitional housing treated as residential of the same type (§ 18.60.020 ).
  • Key dimensional standards: 8,000 sf min lot; 60 ft width; 20 ft front, 6 ft side (footnote C), 20 ft rear; 40% coverage; 35 ft height (§ 18.104.010 ). RM projects must achieve 20–25 du/ac (§ 18.60.070 ) and meet internal spacing/yard/common space minimums (e.g., 12–14 ft building separations; ≥40% site as common use space) (§§ 18.60.080–.100 ).

RC — Residential Country

  • Purpose: Low‑density single‑family near urban areas or major recreation, where soils/slopes allow (§ 18.64.010 ).
  • Typical permitted uses: One single‑family dwelling per lot; agriculture and public stables; ADUs/JADU; small/large day care; small/medium residential care; one guest cottage with conditions (§ 18.64.020 ).
  • Key dimensional standards: 10 acres minimum lot area; 60 ft width; 20 ft front/side/rear; 35 ft height (§ 18.104.010 ). Parcels ≤2 acres in RC use RS side yard standards (§ 18.104.010(B) ).

I — Industrial

  • Typical dimensional standards: 20,000 sf minimum lot area; 100 ft width; 20 ft front/side/rear; 35% coverage; 35 ft height (§ 18.104.010 ).
  • Typical permitted uses: Not found in retrieved materials.

IP — Industrial Park

  • Purpose and framework: IP districts carry a unified site/architectural/landscape/signage intent, with a development‑plan option (§§ 18.40.040, 18.40.250 summaries) ; ; .
  • Key dimensional standards: Minimum lot size generally 5 acres (with exceptions for integrated development plans); minimum width 125 ft; 35% site coverage (up to 50% for high‑warehouse operations per table in § 18.40.040(C)); 35 ft height (§ 18.104.010; § 18.40.040(A)–(C) ; ).
  • Setbacks: Vary by plan; use the Schedule/plan. Verify with the jurisdiction.

GI — General Industrial

  • Purpose and framework: General industrial with explicit dimensional controls and adjacency protections (§§ 18.44.040–.060 ; ).
  • Key dimensional standards: 20,000 sf minimum lot area; 100 ft min width; 50% max lot coverage; 35 ft height (§ 18.44.040 ).
  • Setbacks: Along State Route 29, 55 ft average with 45 ft minimum; other streets 20 ft; sides and rear generally none; special increased setbacks next to IP or residential zones, and landscaping/screening where abutting residential (§ 18.44.060(A)–(B) ). Parking must be on‑site (§ 18.44.080 ).

PL — Public Lands

  • Key dimensional and design standards: In Ag Resource or AWOS General Plan areas, 10 acres minimum lot area (§ 18.50.040 ). Front yard setbacks: 45 ft if adjacent to State Highway or Silverado Trail, 20 ft otherwise (§ 18.50.050(A) ). Requires front‑yard landscaping and screening near residential (§ 18.50.060 ).
  • Typical permitted uses: Not found in retrieved materials.

NP — Napa Pipe districts (NP‑MUR‑W, NP‑IBP‑W, NP‑IBP)

  • Purpose: A special district with its own design guidelines/plan, enabling a walkable mixed‑use neighborhood with industrial/business park components (§§ 18.66.010–.030 ; ).
  • Key dimensional standards: In NP‑MUR‑W, max height 55 ft (§ 18.66.110(A) ); in NP‑IBP‑W, max height 48 ft (§ 18.66.180(A) ). Site coverage in NP‑IBP‑W governed by guidelines and not to exceed 50% unless provided in the plan (§ 18.66.190 ). Lot size maximums: 2.7 acres (MUR) and 20 acres (IBP‑W) with minimums per the approved development plan (§§ 18.66.100, 18.66.200 ; ). Building/parking setbacks and landscaping are per the NP design guidelines/approved plan (§§ 18.66.120, 18.66.210, 18.66.260 ; ; ).

Special, countywide development rules you should not miss

  • Winery coverage and setbacks (open space areas): Maximum “winery coverage” is the lesser of 25% of the parcel or 15 acres; winery setbacks are typically 600 ft from the centerline of any state highway/Silverado Trail or 300 ft from other public/private roads used by the public (§§ 18.104.220–.230(A) ; ). Portions of caves are handled distinctly; see text (§ 18.104.230(A) ). Noncompliant approvals may be revoked (§ 18.104.230(D)–(E) ).
  • Accessory Dwelling Units (ADUs): Napa County implements state allowances. Baselines include at least 4 ft side/rear setbacks; height limits vary by context, with local rules integrating the state’s 16–18–25 ft framework for exempt ADUs and up to 35 ft in some non‑exempt cases; see § 18.104.180 (e.g., setbacks and selected height and parking provisions) ; . For state overlay rights and limits, see California ADU law.
  • Yard definitions and road setbacks: Yards are measured from the outer edge of any required road setback; do not assume the property line controls (§ 18.08.650 ).
  • Viewshed Protection Program: Hillside and ridgeline construction is subject to added siting/design limits to protect scenic quality (§ 18.106.010–.020 ). Confirm early if your parcel is on a designated ridgeline or hillside.

For related topics you may need while laying out a site plan, see Napa County Zoning and Napa County Design Review. Parking, signs, landscaping, and any nonconformities are tightly regulated; start with Napa County Parking, Napa County Signage, Napa County Landscaping and Screening, and Napa County Nonconforming Uses. If you can’t meet an objective standard, read Napa County Variances and Exceptions. For a broader context, the Napa County zoning & planning overview and Napa County Land Use pages help show how Title 18 implements the General Plan.

Quick reference table — Selected dimensional standards (unincorporated)

District Minimum Lot Area Yards (F/S/R) Max Coverage Height Notes Code Reference
AP 40 acres 20/20/20 ft — 35 ft RS side yards apply on parcels ≤2 acres § 18.104.010(B)–Table
AW 160 acres 20/20/20 ft — 35 ft RS side yards apply on parcels ≤2 acres § 18.104.010(B)–Table
RS 8,000 sf 20/6/20 ft 50% 35 ft Side yard “6C”; 5 ft if lot width <60 ft § 18.104.010 & fn C
RM 8,000 sf 20/6/20 ft 40% 35 ft Density 20–25 du/ac §§ 18.104.010; 18.60.070 ;
RC 10 acres 20/20/20 ft — 35 ft § 18.104.010
I 20,000 sf 20/20/20 ft 35% 35 ft § 18.104.010
IP varies; often 5 acres varies 35–50% 35 ft Warehouse coverage can scale up to 50% § 18.40.040; § 18.104.010 ;
GI 20,000 sf 55/0/0 ft along SR‑29; else 20/0/0 50% 35 ft Special adjacency/landscape setbacks §§ 18.44.040–.060 ;
PL 10 acres (in Ag/Watershed G.P. areas) 45 ft front on Hwy/Silverado; 20 ft other — 35 ft Landscaping/screening required §§ 18.50.040–.060
NP‑MUR‑W max 2.7 acres/lot per plan per plan 55 ft Plan/guidelines govern §§ 18.66.100–.120
NP‑IBP‑W max 20 acres/lot per plan up to 50% 48 ft Plan/guidelines govern §§ 18.66.180–.210

Checklist

  • Confirm your parcel’s location is in unincorporated Napa County and identify its zoning district on the county map; then pull baseline metrics from § 18.104.010 .
  • Apply countywide yard rules and the road‑setback measurement rule in § 18.08.650 (front yard measured from the outer edge of any road setback) .
  • If industrial, check district‑specific setbacks and adjacency buffers (e.g., GI § 18.44.060) .
  • If proposing a winery or expanding one, apply winery coverage and setbacks (§§ 18.104.220–.230) ; .
  • If building an ADU, integrate § 18.104.180 standards and the state overlay rights; ensure at least a four‑foot side/rear setback where applicable ; see California ADU law.
  • Confirm if any overlay applies (e.g., Viewshed standards in § 18.106.010), which can add siting limits .
  • Verify related standards (e.g., parking, signage, landscaping and screening).
  • If existing structures don’t meet today’s rules, read Nonconforming Uses; if you cannot meet a standard, see Variances and Exceptions).
  • For projects in design‑controlled areas, coordinate early with Design Review.

Risks & Ambiguities

Issue Why it matters What to verify
Road setback vs. property line Front yard starts at the edge of any required road setback (§ 18.08.650), which can push buildings back further than expected Confirm any Chapter 18.112 road setbacks on your frontage; measure yards from that line
GI along SR‑29 Extra‑deep landscaped setback required along SR‑29 (§ 18.44.060(A)(1)(a)) Whether your frontage is SR‑29; apply 55‑ft average/45‑ft min front setback
Small AP/AW/RC lots Side yards default to RS on parcels ≤2 acres (§ 18.104.010(B)) Lot size; which side yard standard applies
Winery siting 600‑ft/300‑ft road‑centerline setbacks and 25% coverage cap can reshape a site (§§ 18.104.220–.230) ; Road centerlines used for measurement; what counts toward “coverage”
NP (Napa Pipe) projects Setbacks/coverage are plan‑driven (§§ 18.66.120, 18.66.210) ; The adopted NP design guidelines and your approved development plan
Viewshed overlay Hillside design rules can limit height/placement (§ 18.106.010) Whether parcel is within viewshed controls; required findings/standards
RM density and spacing RM must meet 20–25 du/ac and spacing/common area minimums (§§ 18.60.070–.100) Unit count, building separations, and ≥40% common use space

Plain-English Summary

In unincorporated Napa County, your zoning district sets the basics: lot size, setbacks, height, and site coverage. Start with the Schedule of Zoning District Regulations (§ 18.104.010), then layer on countywide yard rules, any overlays (like the Viewshed), and any special rules for your use (for example, wineries have unique setbacks and coverage caps). When in doubt, verify setbacks from roads, check for overlays, and confirm whether related rules like parking or landscaping and screening change your layout.

Source References

  • Schedule of Zoning District Regulations: § 18.104.010 (table and footnotes) ;
  • Yard definitions; required yards and fences: §§ 18.08.650, 18.104.260, 18.104.270 ;
  • AP purpose/uses and standards: §§ 18.16.010–.020; § 18.104.010 ;
  • AW purpose/uses and standards: §§ 18.20.010–.020; § 18.104.010 ;
  • RS purpose/uses; deep‑lot rule: §§ 18.52.010–.020, 18.52.040; § 18.104.010 ; ;
  • RM purpose/uses/density/spacing: §§ 18.60.010–.100; § 18.104.010 ; ; ;
  • RC purpose/uses: §§ 18.64.010–.020; § 18.104.010 ;
  • I/IP/GI standards: §§ 18.104.010; 18.40.040; 18.44.040–.080 ; ;
  • PL standards: §§ 18.50.040–.060
  • Napa Pipe districts (NP‑MUR‑W, NP‑IBP‑W, NP‑IBP): §§ 18.66.010–.030, 18.66.100–.210, 18.66.260 ; ; ;
  • Winery coverage/setbacks; enforcement: §§ 18.104.210–.230 ; ;
  • Viewshed Protection Program: §§ 18.106.010–.020
  • ADU standards (selected local text excerpts): § 18.104.180 ;

Sources

Retrieved passages

  • Napa County Zoning Code (§ 2) High relevance
  • CBC § 1 (chapter have) High relevance
  • CBC § 49 (Title 11) High relevance
  • CBC § 21155 (Section 21155.) High relevance
  • Napa County Zoning Code (Chapter 18.66) High relevance
  • Napa County Zoning Code (Section 18.104.250) High relevance
  • Napa County Zoning Code (chapter in) High relevance
  • Napa County Zoning Code (§ 2) High relevance
  • Napa County Zoning Code (Section 18.124.030) Medium relevance
  • Napa County Zoning Code (§ 2) Medium relevance
  • Napa County Zoning Code (§ 18) Medium relevance
  • Napa County Zoning Code Medium relevance
  • CBC § 66314 (§ 66314) Medium relevance
  • Napa County Zoning Code (§ 2) Medium relevance
  • Napa County Zoning Code (§ 7) Medium relevance
  • Napa County Zoning Code (Chapter 17.17) Medium relevance
  • Napa County Zoning Code (Section 18.104.170.) Medium relevance

Cited sections

Frequently asked questions

What are the standard setbacks and height on agricultural land (AP/AW) in unincorporated Napa County?

AP requires a minimum lot area of 40 acres and AW requires 160 acres. In both, the default front/side/rear yard setbacks are 20 ft with a 35 ft maximum height (§ 18.104.010) . On parcels ≤2 acres in AP or AW, side yards default to RS side‑yard standards (§ 18.104.010(B)) .

What can I build on an RS lot, and what are the basic RS development standards?

RS allows one single‑family dwelling per legal lot along with ADUs/JADU and certain care/day care uses (§ 18.52.020) . Baseline standards are 8,000 sf min lot, 60 ft min width, 20 ft front, 6 ft side (5 ft for narrow lots per footnote C), 20 ft rear, 50% coverage, and 35 ft height (§ 18.104.010) .

How dense can RM multifamily developments be, and are there extra site-planning rules?

RM projects must achieve 20–25 dwelling units per acre (§ 18.60.070) and also meet internal spacing and common use space rules (e.g., minimum building separations and at least 40% common use space) (§§ 18.60.080–.100) .

What special setbacks apply to industrial sites, especially along SR‑29?

In the GI district, front setbacks along State Route 29 require a 55‑ft average with a 45‑ft minimum; other streets are 20 ft. Side and rear yards may be zero, but extra buffers and landscaping apply near IP or residential zones (§ 18.44.060) .

I’m planning a winery expansion. What are the coverage and setback limits?

Winery coverage in open‑space areas is capped at the lesser of 25% of the parcel or 15 acres (§ 18.104.220) . Winery structures must be set back 600 ft from state highways/Silverado Trail or 300 ft from other public/private roads used by the public, measured from the road centerline (§ 18.104.230(A)) .

Do ADUs follow different setbacks and height limits?

Yes. The County’s ADU rules require objective allowances like 4‑ft side and rear setbacks in many situations and provide different height paths depending on ADU type/context under § 18.104.180 (with state overlay allowances) ; . See the state framework summarized on California ADU law.

How do I measure my front yard if my lot fronts a county road?

By definition, the “front yard” starts at the outside edge of any required road setback (not at the property line), per § 18.08.650 (which references Chapter 18.112) . Verify if a road setback applies to your frontage before measuring.

Are there hillside or ridgeline constraints that affect setbacks or building placement?

Yes. The Viewshed Protection Program imposes hillside/ridgeline siting and design standards to protect scenic quality (§ 18.106.010–.020) . Confirm whether your parcel triggers Viewshed review early.

What governs setbacks and coverage in the Napa Pipe (NP) districts?

NP districts are governed by adopted design guidelines and an approved development plan. Heights are capped at 55 ft (NP‑MUR‑W) and 48 ft (NP‑IBP‑W), and coverage/setbacks follow the plan/guidelines (§§ 18.66.110, 18.66.180–.210) ; .

Do public lands have special front setbacks?

Yes. In PL, front setbacks are 45 ft along a State Highway or Silverado Trail and 20 ft on other streets; landscaping and screening standards apply (§§ 18.50.050–.060) .

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