San Anselmo — Development Standards

Last reviewed: July 2, 2026

Overview

This reference summarizes what the Town of San Anselmo’s zoning ordinance controls under “Development Standards” (the standards in the Development Standards Table, Table 4A, and related rules). It explains how setbacks, height, lot coverage, density and floor‑area ratio (FAR) are measured and applied across the Town’s districts, and where to look in the Municipal Code for parcel‑specific answers. The controlling rules are in the Town’s zoning chapter (Table 4A and the related Articles) and several specific sections cited below. See the Town-wide zoning overview for context at San Anselmo zoning & planning overview. (Development standards and measurement rules are established in § 10-3.402, § 10-3.403, § 10-3.404 and related sections.)

Important related local pages you may need while using this guide: the Town’s rules about parking, design review, overlay districts, ADUs, land use, and the California statewide code California Building Standards Code (Title 24).

How San Anselmo organizes Development Standards (quick orientation)

• The Town publishes a Development Standards Table called Table 4A; it lists minimum lot area and width, setbacks, lot coverage, FAR, maximum stories/height, and density for each zoning district. The Table is the primary place to read district numeric standards. § 10-3.402 (Table 4A) (Development Standards Table).
• Measurement rules are separate: setback measurement rules are in § 10-3.403 and height measurement rules are in § 10-3.404. Use those sections to translate plan dimensions into code compliance.
• Special area-based rules apply to houses above/below specific elevations and to ridge/hillside zones (see § 10-3.412 and the ridge provisions in § 10-3.404).
• Minor intrusions, exceptions, minor exceptions, variances and Planned Development procedures allow deviations from Table 4A when the findings are met (see § 10-3.406, Article 14 and Article 9).

District-by-district breakdown

Below are the Town’s most commonly used zoning districts and the ordinance text describing each district’s purpose/typical uses and how the development standards apply. For numeric standards you must consult Table 4A (referenced in § 10-3.402); the text below synthesizes the ordinance and highlights the most decision‑relevant numbers that the code shows repeatedly (e.g., residential front setbacks and side setbacks). Always confirm the exact row/column in Table 4A for a parcel because some numeric fields vary by sub‑district, slope, or overlay.

R-1 / Single-Family Residential (including R-1‑H and R-1‑C)

• Purpose & typical uses: Single‑family homes (detached), with accessory dwellings allowed consistent with the code. R-1‑H is the hillside variant with extra controls for ridgelines; R-1‑C is a commercial‑adjacent variant that retains R‑1 form but addresses slope/visibility. See the ordinance descriptions for the R‑1 variants.
• Key dimensional standards (where typical): front setbacks are commonly 20 ft, interior side setbacks commonly 8 ft, street side 12 ft; maximum lot coverage for many R districts is often 35% (see Table 4A); maximum stories typically 2 on modest slopes and 3 under other slope conditions as Table 4A specifies. These numeric defaults come from Table 4A and its footnotes; confirm the exact cell for your parcel. § 10-3.402; measurement rules in § 10-3.403 and § 10-3.404.
• Where it applies: Most residential neighborhoods; R-1‑H and R-1‑C are used where hills/ridgelines and special adjacency conditions exist. Ridge rules cap certain ridge development (see § 10-3.404).

R-2 / Medium Density Residential

• Purpose & typical uses: Allows duplex and triplex forms (density range noted as 6–12 units/acre in the ordinance) and mixed single‑family + ADU in appropriate locations. The ordinance explicitly targets lands adjacent to Sir Francis Drake Boulevard and near commercial uses. See § 10-3.8(d) (district description).
• Key dimensional standards (typical): front setback often 20 ft, interior side 8 ft; density and minimum lot area are defined in Table 4A. FAR and maximum stories follow Table 4A. See § 10-3.402.

R-3 / High Density Residential

• Purpose & typical uses: Allows multi‑unit housing (density 13–30 units/acre) such as apartments and condominiums, compatible in scale with the Town’s character. See § 10-3.8(e) (district description).
• Key dimensional standards: set by Table 4A — expect higher allowable FAR and different lot coverage rules than R-1/R-2; maximum stories and heights vary by slope and district as shown in Table 4A. § 10-3.402.

Professional (P) District

• Purpose & typical uses: Low‑impact professional offices intended to buffer commercial and residential zones; residential uses (single‑family + ADU) are permitted where compatible. See § 10-3.8(g).
• Standards: Refer to Table 4A for setbacks and lot standards; when adjacent to “R” districts the Table establishes minimum adjacent setbacks and transitions. § 10-3.402.

Commercial Districts: C-1 (Neighborhood Commercial), C‑3 (General Commercial), C‑N (Neighborhood)

• Purpose & typical uses: Retail, service, and mixed commercial uses vary by district. Table 3A (Land Use Regulations) describes permitted uses; dimensional standards and adjacency rules live in Table 4A. For example, many commercial zones allow 0 ft front setback where pedestrian orientation is desired; interior setbacks adjacent to residential districts are larger (see Table 4A). § 10-3.402; land use table in the Land Use Regulations article.

Affordable Housing Overlay (AHO)

• Purpose & typical uses: An overlay that may allow higher density/flexibility when at least 40% of units are deed‑restricted for low income; applicants may use alternate objective standards in Title 3, Chapter 20 or standard entitlements. See the AHO text in the ordinance. § 10-3.8(f).

Notes on all districts: Table 4A is the authoritative numeric source; deviations require an exception/minor exception/design review or variance. Design review findings and procedures are separate; consult the Town’s design review page in parallel with Table 4A.

Key measurement and special rules (what trips applicants up)

• Setback measurement — measured to the nearest point of the building or architectural feature to the property/future right‑of‑way line. See § 10-3.403 for definitions and measurement rules.
• Height measurement — height is measured from the average of the highest and lowest points of the lot covered by the building to the highest roof/ridge/parapet. Chimney exceptions and special ridge limits for R‑1‑H / R‑1‑C / R‑1 are in § 10-3.404 (ridge development may be capped at 18 ft above the ridgeline in some cases).
• FAR, Adjusted Floor Area and Lot Coverage — the code defines "FAR", "Adjusted Floor Area", and "Adjusted Lot Coverage" and places caps for single‑family properties, including a 5,000 sq ft overall cap and differing calculations for lots below/above 150 MSL. See § 10-3.412 and Tables 4E/4F for specifics. These definitions control what counts toward FAR and lot coverage.
• Ridge/Hillside controls — for lots in ridge zones there are additional visibility and height findings in § 10-3.404 and design review criteria to minimize visual impact.
• Exceptions and Minor Intrusions — limited exceptions and the Minor Intrusions Table (Table 4B) allow small intrusions into setbacks subject to administrative/design review findings; see § 10-3.406 and Article 14.5 for the minor exceptions process.
• ADUs and two‑unit rules — ADUs have specific objective standards and statewide constraints but remain subject to local lot coverage/FAR/setback rules except where state law limits local restrictions; local ADU standards and exemptions are in Article 6 (e.g., § 10-6.301 et seq.). Consult the Town’s ADU page in parallel.

Quick decision‑relevant table

Checklist — What an applicant must satisfy (initial planning pass)

• Confirm the parcel’s zoning label on the Town Zoning Map and identify the correct Table 4A column (see § 10-3.402).
• Verify setbacks using § 10-3.403 measurement rules (measure to the nearest point; account for any future R/W).
• Calculate height per § 10-3.404 (average grade → roof ridge); check for ridge/hillside caps if the lot is in R‑1‑H / R‑1‑C.
• Compute Adjusted Floor Area and Adjusted Lot Coverage using definitions in § 10-3.412 and check the 5,000 sq ft cap where applicable.
• Check whether the project needs design review and prepare to show how bulk, massing, screening and landscaping meet design findings (see design review procedures).
• If proposing an ADU, apply the ADU objective standards (Article 6) and confirm which local ADU exemptions apply; cross‑check with state ADU law.
• If you intend to deviate from Table 4A, determine if the change is a Minor Exception, Exception, Planned Development, or Variance and prepare the required findings and noticing.

Risks & Ambiguities

Plain‑English summary

San Anselmo’s Development Standards are set in a master table (Table 4A) and measured using explicit rules: measure setbacks to the nearest point of the building, measure height from average lot grade to top of roof, and compute FAR using the code’s “adjusted” definitions. Residential streets typically expect 20 ft front setbacks and 8 ft interior side setbacks, lot coverage and FAR caps vary by district and slope, and ridge/hillside lots face stronger limits and design review. Always confirm the parcel’s zoning column in Table 4A and run your calculations against the definitions in § 10-3.412; design review, minor‑exception routes, or variances are the normal ways to get small or larger deviations.

Information Gaps

• The uploaded materials include Table 4A and Table 4E as excerpts but not a clean, labeled Table 4A header mapping every column to a district in one visible render in the retrieval snippets; parcel‑specific numeric confirmation should be taken from the official Table 4A cell that matches the parcel’s zoning label on the Town map. (Table 4A is referenced in § 10-3.402; verify the exact Table 4A cell in the Municipal Code.)
• The exact list of permitted uses per district (Table 3A / Land Use Regulations) is not reproduced in full in the retrieved snippet set. Consult the Land Use Regulations Table for permitted/conditional uses for each district. Verify with the jurisdiction.

Source References

• San Anselmo Municipal Code — Development Standards Table (Table 4A) and Article 4 (Development Standards): § 10-3.402.
• Setback measurement rules: § 10-3.403.
• Height measurement and ridge/hillside rules: § 10-3.404.
• Definitions and adjusted FAR / adjusted lot coverage; 5,000 sq ft residential cap and Tables 4E/4F: § 10-3.412 and Table 4E.
• ADU development standards and objective ADU rules: Article 6 (e.g., § 10-6.301 et seq.).
• Minor exceptions and variances (process and findings): Article 14.5 (minor exceptions) and Article 14 (variances).
• District descriptions (R‑2, R‑3, Professional, AHO): § 10-3.8(d)–(g) and related ordinance text describing districts.

Retrieved passages

• San Anselmo Zoning Code (Section 10-3.1404) High relevance show source text
• San Anselmo Zoning Code (section may) High relevance show source text
• San Anselmo Zoning Code (Section is) High relevance show source text
• San Anselmo Zoning Code (§ 1) High relevance show source text
• San Anselmo Zoning Code (Chapter and) High relevance show source text
• San Anselmo Zoning Code (Article 15) High relevance show source text
• California Fire Code (Title 7) High relevance show source text
• San Anselmo Zoning Code (Section 10-3.404) High relevance show source text
• San Anselmo Zoning Code (Section 5020.1) High relevance show source text
• San Anselmo Zoning Code (title across) High relevance show source text
• San Anselmo Zoning Code (§ 1) Medium relevance show source text
• San Anselmo Zoning Code (Chapter 4) Medium relevance show source text
• San Anselmo Zoning Code (§ 1) Medium relevance show source text

Cited sections

• San Anselmo Municipal Code — Development Standards Table (Table 4A) and Article 4 (Development Standards): **§ 10-3.402**. (Article 4)
• Setback measurement rules: **§ 10-3.403**. (§ 10-3.403)
• Height measurement and ridge/hillside rules: **§ 10-3.404**. (§ 10-3.404)
• Definitions and adjusted FAR / adjusted lot coverage; 5,000 sq ft residential cap and Tables 4E/4F: **§ 10-3.412** and Table 4E. (§ 10-3.412)
• ADU development standards and objective ADU rules: Article 6 (e.g., **§ 10-6.301** et seq.). (Article 6)
• Minor exceptions and variances (process and findings): Article 14.5 (minor exceptions) and Article 14 (variances). (Article 14.5)
• District descriptions (R‑2, R‑3, Professional, AHO): **§ 10-3.8(d)–(g)** and related ordinance text describing districts. (§ 10-3.8)
• SanAnselmo_ZoningCode.md

• Official San Anselmo code library