Local zoning · Fairfax

Fairfax — Development Standards

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

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Last reviewed: July 2, 2026

Overview

This page summarizes the Town of Fairfax zoning development standards that govern setbacks, height, lot coverage, density, and floor area ratio (FAR) under Title 17 (Zoning). It pulls the controlling local code sections and explains how they apply by district. For code background see the Town's Fairfax Zoning and for related land‑use context see Fairfax Land Use.

Note: this page interprets the Town of Fairfax ordinance text; always confirm parcel‑specific rules with the Town. Where the local code is silent on a detail I note "Not found in retrieved materials."

Key town‑wide rules (quick reference)

  • Front setback: ten feet; rear setback: ten feet; side setback: five feet (special rule where lot width < 50 ft). See § 17.040.020.
  • Residential lot coverage (general): 35% maximum for residential zones (swimming pools excepted). See § 17.040.010.
  • Maximum FAR for single‑family / duplex lots: 0.40 (and maximum floor area 3,500 sq ft). See § 17.136.030.
  • General building height (residential): 28.5 ft (≤10% slope); 35 ft on downhill lots >10% slope; accessory structures generally 15 ft. See § 17.100.080 and § 17.124.060.
  • ADU-specific limits (setbacks, FAR, lot coverage, parking exceptions) are in Chapter 17.048 (ADU rules) — e.g., side/rear setbacks 4 ft, front 10 ft, ADU cannot cause total FAR > 40%, and lot coverage caps apply (see § 17.048 summaries). See § 17.048 provisions.
  • Waivers: the Planning Director may grant up to 10% relief for many dimensional standards (setbacks, lot coverage, height up to 10% or 2 ft), but waivers cannot change lot area, max stories, minimum parking, minimum/maximum density, or maximum FAR. See § 17.044.090.

(Links to related topics used inline above: Fairfax Design Review, Fairfax Overlay Districts, Fairfax Parking, Fairfax ADUs, California Building Standards Code, Fairfax Landscaping and Screening.)

District‑by‑district breakdown

The Town establishes named zones in Title 17; see § 17.012.010 for the full list of zone labels.

Below are the most decision‑relevant districts with the standards the ordinance provides or points to. For many numeric standards the code applies town‑wide rules above; where a district provides special limits I cite the specific §.

RS-7.5 (single‑family residential — medium density)

  • Purpose / typical uses: single‑family dwellings consistent with the General Plan. Zone name is listed in § 17.012.010.
  • Dimensional standards: The code establishes town‑wide residential setbacks and lot coverage (see § 17.040.020 and § 17.040.010) and FAR cap 0.40 for single‑family/duplex (see § 17.136.030). Specific RS‑7.5 numeric table entries were Not found in retrieved materials; verify with the Town.

RS-6 (single‑family residential — higher density)

  • Purpose / typical uses: single‑family dwellings at a denser pattern than RS‑7.5. See § 17.012.010.
  • Dimensional standards: rely on town‑wide residential rules for setbacks, lot coverage (35%), and FAR 0.40 unless a zone chapter provides different numbers (Not found in retrieved materials for zone‑specific exceptions). See § 17.040.020, § 17.040.010, § 17.136.030.

RD 5.5‑7 (residential)

  • Purpose / typical uses: multi‑lot residential variety (density range in chapter title). See § 17.012.010.
  • Dimensional standards: general setbacks, coverage and FAR rules apply; the RD chapter content was Not found in retrieved materials for parcel‑level numbers—verify. See town‑wide §§ referenced above.

RM / RM‑S (multiple‑family residential / senior)

  • Purpose / typical uses: multi‑family housing and senior‑oriented multi‑family; design and density rules appear in RM chapters. See § 17.012.010.
  • Dimensional standards: multi‑family rules may allow different coverage, setback and parking standards; the code points to multi‑family design standards (Article IV, Chapter 17.138 for multifamily design). Specific numeric entries for RM/RM‑S were Not found in retrieved materials — check the RM chapter and multifamily design chapter.

CC — Central Commercial (§ 17.100 series)

  • Purpose / typical uses: downtown/central commercial uses and mixed uses; see § 17.100.010–.
  • Key standards:
    • Building height: generally 28.5 ft on low‑slope lots; up to 35 ft on downhill lots >10% slope (applies often across commercial/residential chapters) — see § 17.100.080.
    • Yards: No yards required except where CC borders residential zone, in which case CC property must provide yard space equal to abutting residential yards (see § 17.100.090).
    • Off‑street parking and loading: regulated in § 17.100.110; parking chapter cross‑references Chapter 17.052. See Parking link above.

CH — Highway Commercial

  • Purpose / typical uses: highway‑oriented commercial uses (auto‑oriented services). Zone listed at § 17.012.010.
  • Dimensional standards: commercial height rules and driveway standards apply; sidewalk/front setback for sidewalks is 7 ft where no public sidewalk is provided for commercial/industrial zones, per § 17.040.030 (commercial zones). Specific CH chapter (17.096) should be checked for CH‑specific yard/coverage numbers (Not found in retrieved materials).

CL / CS / CR (Limited Commercial, Commercial Service, Commercial Recreation)

  • Purpose / uses: local retail and service uses; each is listed in § 17.012.010.
  • Dimensional standards: the general rules (setbacks, lot coverage, height) and zone chapters govern; specifics for CL/CS/CR numeric values were Not found in retrieved materials. Verify with the code chapters (17.092, 17.104, 17.108).

PDD — Planned Development District (Chapter 17.112)

  • Purpose: flexible, master‑planned projects where standards can be set by plan; requires master plan and precise development plan (see § 17.112.020–.030).
  • Key points: minimum area normally five acres, but the Planning Commission can accept smaller under findings; PDD projects use standards of the most similar base district or standards on the approved development plan. See § 17.112.020 and § 17.112.030.

SF‑RMP — Single‑Family Residential Master Planned District (Chapter 17.116)

  • Purpose / typical uses: master‑planned large‑lot single‑family developments; density range typically 1 unit per 1–10 acres. See § 17.116.010.
  • Permitted uses: one single‑family dwelling per legal building site, up to two accessory dwelling units subject to Chapter 17.048; agriculture and limited residential care are allowed outright (see § 17.116.030, § 17.116.050).
  • Dimensional standards / design: substantial site planning, clustering, ridgeline and ecological protections; height: no part of a building shall exceed 35 ft and accessory bldgs 15 ft (see § 17.116.080).

UR — Upland Residential (Chapter 17.124)

  • Purpose / typical uses: large lot / hillside residential uses; permitted uses restricted to one single‑family dwelling per lot; accessory uses and limited conditional uses listed in § 17.124.020–.040.
  • Key standards: minimum width 60 ft and other building site requirements tie to General Plan classifications; height rules mirror other residential height rules (see § 17.124.050–.070).

WHO — Workforce Housing Overlay (WHO‑A / WHO‑B)

  • Purpose: overlay intended to allow workforce housing incentives; listed under zone categories in § 17.012.010.
  • Application: When WHO applies, overlay standards or incentives modify base zone rules; full WHO text Not found in retrieved materials — verify with overlay chapter 17.126. Not found in retrieved materials for numeric specifics.

Decision‑relevant standards table

Standard or permitted use Typical town limit / rule Code reference
Front setback (residential) 10 ft § 17.040.020
Rear setback (residential) 10 ft § 17.040.020
Side setback (residential) 5 ft (lot width <50 ft: 10% of width, min 3 ft) § 17.040.020
Lot coverage (residential) 35% (standard for residential zones) § 17.040.010
Max FAR (single‑family / duplex) 0.40 § 17.136.030(A)
Max floor area (SFR/duplex/townhouse) 3,500 sq ft (cap regardless of lot size) § 17.136.030(B)
Residential height (general) 28.5 ft (≤10% slope); 35 ft on downhill lots (>10% slope) § 17.100.080
Accessory bldg height 15 ft unless §17.048 governs ADU § 17.100.080(B)
ADU setbacks 4 ft side/rear; 10 ft front (ADU exceptions apply) § 17.048 (ADU provisions)
ADU FAR ADU may not cause total lot FAR > 40% § 17.048 (ADU provisions)
Waiver limits Up to 10% relief for many dimensional standards; waivers cannot change max FAR, lot area, max stories, min parking, or density § 17.044.090

Checklist (what an applicant must satisfy)

  • Confirm base zone for the property on the zoning map and read the zone chapter (see § 17.012.020).
  • Meet basic dimensional standards: setbacks § 17.040.020, lot coverage § 17.040.010, FAR § 17.136.030, and height limits § 17.100.080.
  • If proposing an ADU, follow Chapter 17.048 (setbacks, ADU FAR, lot coverage, parking exceptions). See Fairfax ADUs.
  • Determine whether design review applies (new residences, sizable remodels, commercial exterior changes); follow § 17.020 design review criteria and submittal rules. See Fairfax Design Review.
  • Check for overlays (e.g., WHO or Hill Area Residential Development) that add requirements — see Chapter 17.072 and 17.126. See Fairfax Overlay Districts.
  • Provide required parking per Chapter 17.052, or use ADU parking exceptions (see § 17.048). See Fairfax Parking.
  • If requesting dimensional relief, submit a waiver application per § 17.044.100 and meet waiver findings in § 17.044.090 (waiver limits noted above).
  • Prepare landscape documentation complying with MWELO and any buffer/screening standards (see Chapter 17.138). See Fairfax Landscaping and Screening.

Risks & Ambiguities

Issue Why it matters What to verify
Height measurement on sloped lots Town uses upslope/downslope rules and measures to adjacent natural/finished grade; building height limits differ by slope and position on street, which affects allowable building mass. Verify lot slope category and which height rule applies; check § 17.100.080 and local ridgeline rules § 17.060.
ADU conflicts with local caps (FAR, lot coverage) State ADU law limits how much local rules can preclude ADUs; town code applies limits but must respect state minimums. Confirm ADU-specific rules in Chapter 17.048; reconcile with state ADU law. See § 17.048 (ADU) and state ADU law (linked in sources).
Waiver exclusions Waivers cannot change max FAR, lot area, max stories, min parking or density — so some relief requests will be rejected. If your requested change implicates FAR or density, plan alternative approaches (e.g., redesign or variance). See § 17.044.090.
PDD / master plan flexibility PDDs can set alternative standards, but PDD approval is a multi‑step, public, and often lengthy process. Confirm whether PDD approach is feasible for your site and understand master plan and precise plan requirements § 17.112.
District‑specific numbers not in retrieved excerpts Some district chapters (CL, CH, RM, RM‑S, RD, WHO) have details not found in supplied excerpts. Pull the full text of the specific zone chapter for numeric yard/coverage/height requirements or ask the Planning Department. See § 17.012.010 for zone list.

Plain‑English Summary

Fairfax's zoning code uses a compact set of town‑wide dimensional standards—10 ft front & rear setbacks, 5 ft side setback, 35% lot coverage for most residences, and a typical single‑family FAR limit of 0.40 and 3,500 sq ft cap—plus district chapters that add particular uses or master‑plan rules; accessory dwelling units, ridgeline protections and overlays (e.g., SF‑RMP, UR, WHO) add special rules and some numeric exceptions. Always confirm the applicable zone chapter and whether design review, overlays, or PDD/master‑plan requirements apply. See the controlling code sections cited below.

Source References

  • Title 17: Zoning (Town of Fairfax) — zone list and chapter map (Title 17 table of contents) § 17.012.010.
  • General zone regulations: § 17.040.010 (Lot coverage) and § 17.040.020 (Setbacks).
  • Waivers and limits on relief: § 17.044.090 and § 17.044.100 (waiver process).
  • FAR and maximum floor area caps: § 17.136.030 (FAR 0.40; 3,500 sq ft cap).
  • Residential height rules: § 17.100.080 (general residential height) and § 17.124.060 (UR height rules).
  • ADU chapter and limits (setbacks, ADU FAR, parking exceptions): Chapter 17.048 (ADUs).
  • SF‑RMP (Single‑Family Residential Master Planned District): Chapter 17.116 (purpose, uses, design).
  • PDD (Planned Development District): Chapter 17.112 (master plan / standards).
  • Design review applicability and criteria: Chapter 17.020.
  • Landscaping / buffering & screening: Chapter 17.138 excerpts (landscape documentation and buffer rules).

If you want the full text of any cited chapter or a parcel‑specific check (e.g., exact zone for an Assessor’s Parcel Number), tell me the parcel/APN or which chapter you want and I’ll extract the specific sections and map applications. Verify with the Town of Fairfax Planning Department for parcel‑level determinations.

Sources

Retrieved passages

  • Fairfax Zoning Code (§ 17.044.100) High relevance
  • CFC § 17.60.060 (§ 17.60.060) High relevance
  • Fairfax Zoning Code (§ 7060-7060.7) High relevance
  • Fairfax Zoning Code (Chapter 17.044) High relevance
  • CWUIC § 17.138.600 (Chapter 2.7) High relevance
  • Fairfax Zoning Code (§ 65589.5) High relevance
  • CBC § 66314 (§ 66314) High relevance
  • Fairfax Zoning Code High relevance
  • CBC § 17.66.040 (Chapter 17.048) High relevance
  • Fairfax Zoning Code (§ 17.60.070) High relevance
  • Fairfax Zoning Code (§ 17.020.040) Medium relevance
  • Fairfax Zoning Code (CHAPTER 17.124) Medium relevance
  • CFC § 17.040.040 (§ 17.040.040) Medium relevance
  • Fairfax Zoning Code (§ 17.020.030) Medium relevance
  • Fairfax Zoning Code (§ 17.60.130) Medium relevance

Cited sections

Frequently asked questions

What can I build on an R‑1 (RS‑7.5/RS‑6) lot in Fairfax?

You can build uses permitted by the applicable single‑family residential zone and the Fairfax General Plan; typical permitted use is one single‑family dwelling per lot with accessory uses (e.g., garages, ADUs subject to Chapter 17.048). Numeric dimensional constraints (setbacks, lot coverage, FAR) are set by the town‑wide rules: setbacks § 17.040.020, lot coverage § 17.040.010, and FAR caps § 17.136.030; check the specific RS chapter for any local differences.

What are Fairfax setback requirements?

The baseline setbacks are 10 ft front, 10 ft rear, and 5 ft side (with a small‑lot formula where average width < 50 ft) per § 17.040.020. Some zone chapters or overlays can require additional standards; waivers up to 10% may be available under § 17.044.090.

What is the maximum FAR and floor area for a single‑family home in Fairfax?

For single‑family residences and duplexes the code caps FAR at 0.40 and overall maximum floor area at 3,500 sq ft (subject to exclusions like certain accessory structures and garages). See § 17.136.030 for the calculation rules and exclusions.

Do I need design review for my house addition?

Design review applies to new residences and additions that meet the Town’s remodel threshold (see § 17.020.030 applicability). The design review criteria focus on height, massing, setbacks, materials, landscaping and compatibility with surrounding development (§ 17.020.040). Check whether your project is a >50% remodel or new construction for applicability. See Fairfax Design Review.

What are the ADU setback, FAR and parking rules in Fairfax?

ADUs under Chapter 17.048 must generally meet 4 ft side/rear setbacks and 10 ft front setback as applicable; an ADU cannot cause total lot FAR to exceed 40% and ADU lot coverage limits apply (see Chapter 17.048). One off‑street parking space is typically required but there are several state‑allowed exceptions; see Chapter 17.048 for the list. See Fairfax ADUs.

Can I get a waiver for setback or height?

Yes — the Planning Director can grant waivers of up to 10% for many dimensional standards (setbacks, lot coverage, certain height allowances up to 10% or 2 ft) provided specific findings are met; waivers cannot alter maximum FAR, lot area, max stories, minimum parking, or density. See § 17.044.090 and the waiver procedure § 17.044.100.

How does slope affect height limits in Fairfax?

Height rules distinguish lots by slope: on lots with ≤10% slope the general limit is 28.5 ft and on lots with >10% slope the downhill side may go to 35 ft (and uphill side can be limited differently). The code measures height relative to natural/finished grade per § 17.100.080; confirm lot slope classification with the Town for exact measurement.

If my property is in a PDD or SF‑RMP, do general rules still apply?

PDD and SF‑RMP allow plan‑level standards and master planning. PDD projects adopt standards via a master plan and precise development plan; SF‑RMP imposes master plan design and open‑space requirements and can modify standard yard requirements § 17.112 and § 17.116. However, where a PDD or SF‑RMP is silent the general Title 17 rules still provide the baseline—always review the approved plan and the PDD/SF‑RMP chapter.

Are there any special creek setbacks or environmental buffers?

Yes — buildings adjacent to Fairfax and San Anselmo creeks have a minimum setback of 20 ft or two times average bank depth, whichever is greater, absent a variance (see § 17.040.040). Landscaping, tree removal and wildlife habitat protections are also applied in specific districts and overlays (see Chapter 17.072 and related site prep rules).

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