Local zoning · Marin County

Marin County — Development Standards

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

Last reviewed: July 6, 2026

Overview

In unincorporated areas of Marin County, development standards—setbacks, height, floor area ratio (FAR), density, and related dimensional limits—are established in the Marin County Development Code. Two regimes apply: the coastal zone standards in Title 20 (Local Coastal Program Implementation Plan), and the non-coastal standards in Title 22 (Development Code). Where the coastal and inland codes overlap, the Local Coastal Program standards control within the Coastal Zone, and Title 22 still applies for topics like design review and certain permits .

Key rule: In unincorporated coastal areas, site planning must meet the Coastal Zone’s tables for minimum lot area, setbacks, height, and FAR (Table 5‑4), plus any applicable community or combining district standards; in case of conflict with inland rules, the Coastal Program governs (§ 20.64.030; § 20.01.020).

This page distills the standards that are explicit in Marin’s ordinance. For any item the retrieved ordinance does not show, this page marks it as “Not found in retrieved materials.”

How to read Marin’s code in unincorporated areas

Coastal vs. inland. Development in the Coastal Zone follows Title 20’s zoning district tables and resource standards; inland areas follow Title 22. The LCP defers some procedures (e.g., design review) to Title 22, but those apply in addition to Coastal permits where relevant .
The core coastal table. Table 5‑4 in § 20.64.030 lists minimum lot area, density, setbacks, height, and FAR by coastal zoning district; measurement and exceptions live in § 20.64.045 .
Combining districts. The Coastal “‑B” Minimum Lot Size combining district can replace a base district’s lot area and setback rules with those in Table 5‑5 (§ 20.64.040) .
Community standards. Some coastal communities (e.g., Dillon Beach) have customized setbacks/height that supersede the base district (§ 20.66.110) .

Core property development standards (coastal zone)

Setback measurement and exceptions. § 20.64.045 defines how to measure front, side, street-side, and rear yards; it also lists what can encroach into setbacks (e.g., chimneys, porches, decks) per Table 3‑1 (e.g., decks may project 6 ft into the front or rear, 3 ft into the side) .
Height limits and exceptions. Detached accessory structures are generally capped at 15 ft; they may match primary structure height if set 40 ft from all property lines. Limited height exceptions apply for features like chimneys and cupolas, with strict caps and no floor area use (§ 20.64.045.C) .
Fences/walls in setbacks. Up to 4 ft solid or up to 6 ft if the portion above 4 ft is at least 50% open may be placed in front/street-side setbacks (§ 20.64.045.B) .
Steep-lot parking relief. On steep sites (≥20% slope across the front half) or where the parcel elevation at the access side differs by ≥5 ft from the street, a parking structure can be as close as 3 ft to the front and street-side property lines (§ 20.64.045.E.5.b) .
Environmental buffers. Additional setbacks may be triggered by Environmentally Sensitive Habitat Areas and hazards; buffers and avoidance are set in § 20.64.050 and the LCP biological policies .

District-by-district standards (coastal zone)

Below are the coastal districts with purposes, typical outcomes, and the dimensional standards the retrieved tables show. Where a value is not visible in the retrieved table text, it is identified as “Not found in retrieved materials.” Always confirm parcel overlays in the overlay districts and check nonconforming status before relying on past conditions.

C-RA — Coastal Residential, Agricultural

Purpose/use: Coastal residential with agricultural context; 1 unit per minimum lot area required (density shown generically in Table 5‑4) .
Key dimensional standards: Front setback 25 ft; sides 6 ft (10 ft street-side); rear 20% of lot depth (max 25 ft). Accessory structure height 15 ft (§ 20.64.030; § 20.64.045.C.2) .
FAR: Not found in retrieved materials.
Where it applies: Unincorporated Coastal Zone residential areas.

C-R1 — Coastal Single-Family Residential

Purpose/use: Single-family coastal neighborhoods.
Key dimensional standards: Front 25 ft; sides 6 ft (10 ft street-side); rear 20% of lot depth (max 25 ft); accessory height 15 ft (§ 20.64.030; § 20.64.045.C.2) .
FAR: 0.30 (Table 5‑4) .
Where it applies: Unincorporated coastal residential tracts.

C-R2 — Coastal Multi-Family Residential

Purpose/use: Multi-family or higher-density residential within the Coastal Zone.
Key dimensional standards: Front 25 ft; sides 6 ft (10 ft street-side); rear 20% of lot depth (max 25 ft); accessory height 15 ft (§ 20.64.030; § 20.64.045.C.2) .
FAR: Not found in retrieved materials.
Where it applies: Unincorporated coastal residential areas that allow multi-family.

C-VCR — Coastal, Village Commercial/Residential

Purpose/use: Historic “main street” settings; supports resident- and visitor-serving commercial with compatible housing above/behind storefronts (§ 20.62.080.B.1) .
Key dimensional standards: Minimum lot area 7,500 sq ft. Density 1 unit/2,000 sq ft of lot area. Front setback 0 ft. Sides: 0 ft for commercial, 5 ft for residential. Rear: 0 ft for commercial, 15 ft for residential. Max height 25 ft (Table 5‑4) .
Where it applies: Coastal village cores in unincorporated areas.

C-H1 — Coastal, Limited Roadside Business

Purpose/use: Rural highway-serving businesses (§ 20.62.080.B.2) .
Key dimensional standards: Front 30 ft; sides 6 ft when adjacent to a residential district, otherwise none; rear 12 ft when adjacent to a residential district, otherwise none (Table 5‑4) .
Max building height and FAR: Not found in retrieved materials.
Where it applies: Rural commercial nodes along coastal highways.

C-CP — Coastal, Planned Commercial

Purpose/use: Full range of commercial and institutional uses (§ 20.62.080.B.3) .
Dimensional standards: Not found in retrieved materials (consult Table 5‑4).
Where it applies: Designated coastal commercial areas, unincorporated.

C-RMPC — Coastal, Residential/Commercial Multiple Planned

Purpose/use: Planned mixed residential/commercial (§ 20.62.080.B.4) .
Dimensional standards: Not found in retrieved materials (consult Table 5‑4).
Where it applies: Planned mixed-use sites in the Coastal Zone.

C-RCR — Coastal, Resort and Commercial Recreation

Purpose/use: Resort facilities emphasizing public recreation and access (§ 20.62.080.B.5) .
Dimensional standards: Not found in retrieved materials (consult Table 5‑4).
Where it applies: Coastal recreation/resort destinations, unincorporated.

C-APZ — Coastal, Agricultural Production Zone

Purpose/use: Preserve working agricultural lands (§ 20.62.060.B.1) .
Key dimensional standards: Max residential density 1 unit per 60 acres (§ 20.62.060.B.1). Maximum combined residential floor area tied to CDP findings; in C‑APZ, agricultural dwelling floor area is limited to 7,000 sq ft plus 540 sq ft garage and 500 sq ft office used with the farm operation (§ 20.64.045, Table notes) .
Where it applies: Agricultural landscapes in the Coastal Zone.

C-ARP — Coastal, Agricultural Residential Planned

Purpose/use: Cluster residential development to maintain maximum land for agriculture and protect resources (§ 20.62.060.B.2) .
Dimensional standards: Governed by clustering and applicable LCP standards; specific setbacks/height not found in retrieved materials.
Where it applies: Transitional agricultural-residential areas.

C-OA — Coastal, Open Area

Purpose/use: Open space and outdoor recreation, access to beaches, drainage channels, greenway connections (§ 20.62.060.B.3) .
Dimensional standards: Not found in retrieved materials.
Where it applies: Public/quasi-public open space in the Coastal Zone.

C-RSPS — Seadrift Subdivision (Special Planned District)

Purpose/use: Planned standards tailored to Seadrift’s sensitive coastal setting (§ 20.65.070.A–B) .
Key dimensional standards: Required ocean-side building setback line on lots fronting the ocean (§ 20.65.070.C). Height limited by NAVD-based elevation caps: in most Seadrift areas, finished floor ≤19.14 ft NAVD and total height ≤34.14 ft NAVD; in specific lagoon areas, finished floor ≤14.14 ft NAVD and total height ≤29.14 ft NAVD (§ 20.65.070.D) .
Where it applies: Seadrift (Stinson Beach) in unincorporated Marin’s Coastal Zone.

Coastal “-B” Minimum Lot Size Combining District (B1–B6; BD)

Purpose/use: Replace base-district lot area and setback rules where applied (§ 20.64.040.A–B) .
Key dimensional standards (Table 5‑5):
- B1: Min lot 6,000 sq ft; front 25 ft; sides 5 ft (10 ft street-side); rear 20% lot depth to 25 ft max; primary height 25 ft; accessory height 15 ft; FAR 0.30 .
- B3: Min lot 20,000 sq ft; front 30 ft; sides 15 ft (other cells not shown in retrieved text) .
- B5: Min lot 2 acres; sides 20 ft (30 ft street-side); rear 30 ft (others not shown) .
Notes: In the Stinson Beach Highlands, the primary building height is 17 ft (not 25 ft); single-family homes over 25 ft require a Coastal Zone Variance (§ 20.64.040, Table 5‑5 notes; § 20.70.150 referenced) .

Community-specific standards — Dillon Beach C‑R‑1:B‑D

Purpose/use: Maintain small-scale residential/commercial character (§ 20.66.110.A) .
Key dimensional standards: Front setback 10 ft; sides 5 ft (10 ft street side); rear 10 ft; max height 20 ft; parcels exempt from FAR (§ 20.66.110.B) .

Quick-reference table (selected districts and combining standards)

District	Key dimensional standards (front/side/rear; height; FAR or density)	Typical intent	Where it applies	Code Reference
C-RA	25 ft / 6 ft (10 ft street-side) / 20% depth to 25 ft max; accessory height 15 ft; FAR Not found	Coastal residential w/ ag context	Coastal residential areas	§ 20.64.030; § 20.64.045.C.2
C-R1	Same setbacks as C‑RA; accessory height 15 ft; FAR 0.30	Single-family coastal	Coastal tracts	§ 20.64.030; § 20.64.045.C.2
C-R2	Same setbacks as C‑RA; accessory height 15 ft; FAR Not found	Multi-family coastal	Coastal residential	§ 20.64.030; § 20.64.045.C.2
C-VCR	Lot 7,500 sf min; density 1/2,000 sf; front 0 ft; sides 0 ft (comm)/5 ft (res); rear 0 ft (comm)/15 ft (res); height 25 ft	Village main street mixed-use	Coastal village cores	§ 20.64.030; § 20.62.080.B.1
C-H1	Front 30 ft; sides 6 ft adj. res, none otherwise; rear 12 ft adj. res, none otherwise; other metrics Not found	Roadside business	Rural highway nodes	§ 20.64.030; § 20.62.080.B.2
C-APZ	Density 1 unit/60 acres; ag dwelling floor area cap 7,000 sf + allowances	Protect agriculture	Coastal ag lands	§ 20.62.060.B.1; § 20.64.045 (notes)
C-RSPS (Seadrift)	Ocean building setback line; height caps by NAVD (e.g., 29.14–34.14 ft NAVD tiers)	Site-specific coastal standards	Seadrift (Stinson Beach)	§ 20.65.070.C–D
B1 (‑B combining)	Lot 6,000 sf; 25 / 5 (10 street) / 20% to 25; height 25/15; FAR 0.30	Finer-grain coastal lots	Where mapped with ‑B	§ 20.64.040, Table 5‑5
Dillon Beach C‑R‑1:B‑D	10 / 5 (10 street) / 10; height 20 ft; FAR exempt	Community plan standards	Dillon Beach/Oceana Marin	§ 20.66.110.B

Standards frequently paired with setbacks/height

Allowed projections into setbacks: chimneys 30 in; porches 6 ft; decks 6 ft front/rear, 3 ft side; stairways 6 ft; all with “no closer than 3 ft to any property line” caveat (Table 3‑1) .
Solar and telecom equipment: roof solar may exceed height by up to 2 ft; ground systems under 18 in high are setback‑exempt; telecommunications facilities must meet LCP siting standards (§ 20.32.160–.165 excerpts) .
Accessory Dwelling Units: locally, ADUs must meet zoning setbacks/height/FAR unless preempted by state law; ministerial approval applies where no discretionary permits are triggered (§ 20.32.140). State law ensures at least one 800‑sq‑ft ADU with 4‑ft side/rear setbacks; additional Coastal Zone constraints may apply (Gov. Code summaries) . For policy context see California ADU law.

Inland (non-coastal) standards

Marin’s inland zoning standards (e.g., R‑A, R‑R, R‑1, R‑2, commercial districts) are codified in Title 22. Only references to Title 22 appear in the retrieved materials (e.g., that design review is in § 22.42, and hillside subdivision standards in § 22.82.050 are cross‑referenced), so parcel‑specific inland setbacks/height/FAR could not be verified here. Not found in retrieved materials for numeric inland standards; verify with the Marin County Zoning and Marin County Land Use pages and Title 22 directly. The LCP notes inland standards may also apply procedurally in the Coastal Zone (§ 20.64.045 notes; § 20.01.020) .

Checklist

Confirm whether the parcel is in the Coastal Zone or inland Title 22 area, and whether any combining/overlay applies (e.g., “‑B”) (§ 20.64.040; see overlay districts) .
Identify the base district and pull the applicable table (Table 5‑4 for coastal) for minimum lot area, setbacks, height, and FAR (§ 20.64.030) .
Check community‑specific standards (e.g., Dillon Beach § 20.66.110; Seadrift § 20.65.070) that supersede general rules .
Apply measurement/exception rules for height, fences, and setback projections (§ 20.64.045; Table 3‑1) .
Verify biological/hazard buffers that can add setbacks (§ 20.64.050) .
Cross‑check parking and access—steep‑lot parking relief may adjust front/street-side placement (§ 20.64.045.E.5.b) .
Determine if design review or other Title 22 procedures apply in addition to any Coastal Development Permit (§ 20.64.045 notes; § 20.01.020) .
For ADUs, apply § 20.32.140 and state ADU minimums; in coastal areas, confirm Coastal constraints; see California ADU law .
If standards cannot be met, consider variances and exceptions; e.g., single-family over 25 ft requires a Coastal Zone Variance where noted (Table 5‑5 note; § 20.70.150 referenced) .

Risks & Ambiguities

Issue	Why it matters	What to verify
Coastal vs. inland jurisdiction	Different tables/standards and permits; LCP controls in Coastal Zone	Is the parcel within the Coastal Zone boundary? (§ 20.01.020)
Combining districts (‑B)	Can change lot size and setbacks from base district	Is a “‑B” suffix mapped, and which tier (B1–B6)? (§ 20.64.040, Table 5‑5)
Community standards	Localized setbacks/height trump general	Whether Dillon Beach, Seadrift, etc. apply (§ 20.66.110; § 20.65.070)
Height measurement	Defined from grade; exceptions limited	How height is measured on your site (§ 20.64.045.C)
ESHA/hazard buffers	Can add setbacks beyond district minima	Any ESHA/stream/wetland/hazard buffers (§ 20.64.050)
ADU preemption	State law may override local FAR/lot coverage/setbacks for one 800‑sf ADU	Apply § 20.32.140 and state minima; coastal caveats (Gov. Code summaries)
Inland Title 22 specifics	Inland numeric standards not visible in retrieved text	Title 22 tables for R‑1, C‑1, etc. Not found in retrieved materials. Verify with the jurisdiction

Plain-English Summary

If your property is in unincorporated Marin’s Coastal Zone, start with the district table for your zoning to get the minimum lot size, setbacks, height, and any FAR. Then check whether a “‑B” combining district or a community plan layer (like Dillon Beach or Seadrift) changes those numbers. Apply the measurement/exception rules (what can stick into a setback, how height is measured), confirm environmental buffers, and layer on procedural items like design review and parking. Inland parcels follow Title 22; confirm the exact district table with the County.

Source References

§ 20.01.020 (Applicability; LCP controls; Title 22 references)
§ 20.62.050–.080 (Coastal district purposes; measurement references)
§ 20.62.060.B.1–3 (C‑APZ, C‑ARP, C‑OA purposes; 1 unit/60 acres in C‑APZ)
§ 20.64.020–.030 (Applicability; Table 5‑4 Coastal Zone Development Standards)
§ 20.64.040 (Coastal “‑B” Combining District; Table 5‑5) and notes (height/variance references)
§ 20.64.045 (Property Development and Use Standards; height, fences, encroachments) and Table 3‑1 (projections)
§ 20.64.050 (Biological Resources; ESHA buffers)
§ 20.65.070 (C‑RSPS Seadrift District Standards)
§ 20.66.110 (Dillon Beach C‑R‑1:B‑D standards)
§ 20.32.140 (Accessory Dwelling Units; local standards); State ADU law guide (Gov. Code summaries)

Sources

Retrieved passages

Marin County Zoning Code (§ III) High relevance
Marin County Zoning Code (§ III) High relevance
Marin County Zoning Code (Section 20.65.070.D) High relevance
Marin County Zoning Code (Section 22.82.050) High relevance
Marin County Zoning Code (§ III) High relevance
CBC § 66314 (§ 66314) Medium relevance
Marin County Zoning Code (§ III) Medium relevance
Marin County Zoning Code (Section 22.82.050) Medium relevance
Marin County Zoning Code (Section 20.64.045) Medium relevance
Marin County Zoning Code (§ III) Medium relevance
Marin County Zoning Code (Chapter 20.130) Medium relevance

Cited sections

§ 20.01.020 (Applicability; LCP controls; Title 22 references) (§ 20.01.020)
§ 20.62.050–.080 (Coastal district purposes; measurement references) (§ 20.62.050)
§ 20.62.060.B.1–3 (C‑APZ, C‑ARP, C‑OA purposes; 1 unit/60 acres in C‑APZ) (§ 20.62.060.B.1)
§ 20.64.020–.030 (Applicability; Table 5‑4 Coastal Zone Development Standards) (§ 20.64.020)
§ 20.64.040 (Coastal “‑B” Combining District; Table 5‑5) and notes (height/variance references) (§ 20.64.040)
§ 20.64.045 (Property Development and Use Standards; height, fences, encroachments) and Table 3‑1 (projections) (§ 20.64.045)
§ 20.64.050 (Biological Resources; ESHA buffers) (§ 20.64.050)
§ 20.65.070 (C‑RSPS Seadrift District Standards) (§ 20.65.070)
§ 20.66.110 (Dillon Beach C‑R‑1:B‑D standards) (§ 20.66.110)
§ 20.32.140 (Accessory Dwelling Units; local standards); State ADU law guide (Gov. Code summaries) (§ 20.32.140)
MarinCounty_ZoningCode.md
2025 California ADU handbook.md

Official Marin County code library

Frequently asked questions

What are the typical setbacks for a coastal single-family lot (C-R1) in unincorporated Marin?

Table 5‑4 shows 25 ft front, 6 ft sides with 10 ft on the street side, and rear equal to 20% of lot depth up to a 25 ft maximum. Detached accessory structures are limited to 15 ft in height unless set 40 ft from all property lines (§ 20.64.030; § 20.64.045.C.2) .

How high can I build in the Coastal Zone, and how is height measured?

Maximum heights are set by the district table, measured vertically from grade to a plane parallel to grade; accessory structures are generally capped at 15 ft, with narrow exceptions for features like chimneys (§ 20.64.045.C) .

Do decks, porches, or stairs get to project into coastal setbacks?

Yes. Table 3‑1 allows, for example, porches and decks up to 6 ft into front or rear setbacks and 3 ft into side setbacks; no projection may be closer than 3 ft to any property line (§ 20.64.045.E; Table 3‑1) .

What if my parcel has a “-B” suffix (e.g., C‑R1:B1)?

The “‑B” combining district replaces the base district’s lot area and setback standards with those in Table 5‑5. For example, B1 requires a 6,000‑sf lot, 25‑ft front setback, and 5‑ft sides (10‑ft street side); Stinson Beach Highlands has a 17‑ft primary building height cap noted in the table (§ 20.64.040) .

Are there special rules in Dillon Beach or Seadrift?

Yes. Dillon Beach’s C‑R‑1:B‑D district sets tighter setbacks (e.g., 10‑ft front) and a 20‑ft max height, with FAR exempt. Seadrift (C‑RSPS) has an ocean‑side building setback line and NAVD‑based height caps (§ 20.66.110; § 20.65.070) .

Can a garage be closer to the street on a steep coastal lot?

Possibly. Where the front half of the lot averages 20% slope or the parcel elevation differs ≥5 ft from the street at the access side, a parking structure may be as close as 3 ft to front and street‑side property lines (§ 20.64.045.E.5.b) .

What applies to ADUs in the Coastal Zone?

Local standards in § 20.32.140 say ADUs must meet setbacks/height/FAR unless state law preempts; state law guarantees at least one 800‑sf ADU with 4‑ft side/rear setbacks (with Coastal caveats), and ministerial review where no discretionary permit is triggered (§ 20.32.140; Gov. Code summaries) .

Where do I find inland (non-coastal) standards for R‑1 and commercial zones?

Those are in Title 22. The retrieved materials here did not include the numeric inland tables (“Not found in retrieved materials”). Confirm on the County’s Title 22 pages and via Marin County Zoning.

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