Mill Valley — Landscaping and Screening

Last reviewed: July 2, 2026

Overview

This page summarizes what the Mill Valley Zoning Code (Title 20) requires for landscaping, screening, buffers, fences/walls, and trees. It focuses only on zoning/planning provisions: design-review landscape requirements, planned-development landscape submittals, tree-protection and replacement rules, and the fence-permit rules that control height, location and findings. Key controlling provisions include Design Review (§ 20.66.020 / § 20.66.030 / § 20.66.045), the General Provisions and Exceptions (Chapter 20.60, § 20.60.060 – § 20.60.300) rules on fencing and accessory structures, and the Tree Protection rules in Chapter 20.67 (replacement ratios at § 20.67.150); see the Source References for precise citations and the underlying file previews.

This page links to related Mill Valley guidance where topics intersect: zoning, development standards, parking, design review, overlays, ADUs and the state building code for topics that must defer to Title 24.

• For an overview of the city rules see Mill Valley zoning & planning overview.
• For district maps and permitted uses see Mill Valley Zoning.
• For how landscaping affects dimensional controls see Mill Valley Development Standards.
• For vehicle-area screening rules see Mill Valley Parking.
• For when plantings or fences trigger aesthetic review see Mill Valley Design Review.
• For overlay-specific rules see Mill Valley Overlay Districts.
• For ADU-related yard/setback interactions see Mill Valley ADUs.
• For building-code technical constraints see California Building Standards Code.

(Those internal links are embedded at their first natural mention above.)

What the Code Requires — high‑level synthesis (plain English)

• If your project is subject to Design Review, the City expects it to be "appropriately and adequately landscaped" and to maximize retention of significant existing vegetation; the Design Review chapter authorizes the City to require more restrictive setbacks, yards or additional landscaping depending on site conditions (§ 20.66.020, § 20.66.045).
• Large projects, planned developments and precision development plans must submit a landscape plan (showing existing trees, trees to be removed, proposed plantings, irrigation and maintenance) as part of the master/precise development or site plan submittal. This requirement appears in multiple planned development / master plan / precise-plan submittal lists.
• Fences and walls are regulated for location, height, and appearance: typical residential fences within setbacks may be built without a permit up to 7 ft (interior yards) or 4 ft (exterior/front yards); fences in public rights‑of‑way or taller than the limits need a Fence Permit and must meet specific findings (no sight-line obstruction, structural soundness, aesthetics, animal movement, and additional findings for ROW fences) (Chapter 20.60).
• Trees: the code protects “heritage” and other protected trees. Tree removal for development normally requires a permit and, when removal is approved, replacement planting is required — heritage-tree replacement uses a formula; other removed trees have at least a 1:1 replanting requirement. Replacement specifics are in Chapter 20.67, including § 20.67.150 for replacement trees and related enforcement.
• Retaining walls, driveway and parking screening, trash enclosures and transformer screening are treated as “physical improvements” and often trigger Design Review and landscape-screening expectations.

District‑by‑district implications (what landscaping/screening rules mean in each Mill Valley district)

The Zoning Code defines district names and categories in Chapter 20.12 (Districts Generally, § 20.12.010 – § 20.12.040); the list includes residential districts RS (single family), RM (multi-family), DR (Downtown Residential), R-P (Planned Residential), and commercial districts C-G, C-R, C-F, C-N, plus O-A, U, PD and overlay districts such as H‑O (Historic Overlay) and housing overlays.

Below are district-specific notes that affect landscaping and screening. Each sub‑section names the district, cites the code chapter or section that establishes the district, summarizes the district purpose & typical uses, then gives the most decision‑relevant landscaping/screening points (what an applicant must show or expect). Where the ordinance text provided specific numeric standards for a district those standards are included and cited.

RS — Single‑Family Residential (see Chapter 20.22 / related single‑family chapters)

• Purpose / Typical uses: single family dwellings and accessory structures; used to preserve neighborhood character and limit disturbance. (See district listings at § 20.12.010 – § 20.12.040.)
• Key dimensional standards to watch: Maximum building height 25 ft (typical single‑family cap noted in residential chapters), exterior (front) setback 15 ft, interior setbacks = 1 ft per 1,000 sq ft lot area (min 5 ft / max 15 ft); lot coverage caps vary by RS‑subdistrict (e.g., RS‑6 = 40%) — these are the same development rules that influence how much of a yard is available for screening/landscape.
• Landscaping/screening implications: Design Review may be required for many exterior changes; where required the review body will expect retention of significant trees and an “appropriate and adequate” landscape plan (§ 20.66.020). Fences built inside setbacks normally may be up to 7 ft interior / 4 ft exterior without a permit; higher or ROW fences require a Fence Permit and findings.

RM — Multi‑Family Residential (example: RM‑3.5 / Bayfront District specifics)

• Purpose / Typical uses: multiple family dwellings, supportive uses, accessory structures; Bayfront areas (Enchanted Knolls, Shelter Bay, Shelter Hill, Plymouth Square) are referenced explicitly in the RM chapter as included areas.
• Key dimensional standards (example RM‑3.5): min. land area per unit 3,500 sq ft, max lot coverage 50%, min exterior yard 15 ft, min interior yard 1 ft per 1,000 sq ft (5–10 ft range), max building height at setbacks 25 ft (up to 35 ft beyond twice setbacks). These standards directly govern how much space is available for planting, parking screening and green buffers.
• Landscaping/screening implications: Multi‑family projects must include a landscape plan with planting lists, parking/driveway screening, and tree preservation in master/precise plans; Design Review is routinely required and will apply the same vegetation‑retention expectations and may request added screening between uses.

DR — Downtown Residential

• Purpose / Typical uses: mixed residential density in downtown contexts; special development standards and stepbacks apply.
• Landscaping/screening implications: Downtown sites have smaller setbacks and objective design standards; landscape proposals that affect setbacks, usable outdoor space, or visibility to the street are scrutinized under Design Review (§ 20.66.020) and Downtown design rules (see Mill Valley Development Standards).

R‑P — Planned Residential (Chapter 20.18, § 20.18.010 – § 20.18.110)

• Purpose / Typical uses: allows site‑specific master planning for residential projects where density, layout and open space are set by a master plan.
• Landscaping/screening implications: a master plan must include a preliminary landscape plan (existing trees, trees to be removed, conceptual planting plan), and the precise development plan must include a detailed landscape plan showing plant types, irrigation and maintenance programs. Expect tree preservation and revegetation conditions where appropriate.

Commercial districts — C‑G, C‑R, C‑F, C‑N

• Purpose / Typical uses: general commerce, neighborhood commercial, recreation/community facilities, etc. (District list: § 20.12.010 – § 20.12.040.)
• Landscaping/screening implications: commercial projects are frequently subject to Design Review and must show landscaping for parking lots, loading areas, service yards and perimeter screening. Screening of mechanical equipment and transformers must be shown and integrated with landscaping (special rules for screening of wireless and utility equipment also exist).

PD — Planned Development; OA — Open Area; Overlays (H‑O, Office conversion housing overlay, Small‑Lot, Opportunity Site)

• Purpose / Typical uses: PD and overlays modify base district standards or add procedural requirements. See Chapter 20.12 for overlay names and intent.
• Landscaping/screening implications: PD approvals commonly carry site‑specific landscaping conditions; overlays can trigger objective design standards and may require specific landscape/parking screening plans; consult the overlay chapter and related Development Standards.

Key standards & thresholds (decision‑relevant table)

Practical Guidance / How the rules play out in practice

• If you are doing any exterior change larger than a small accessory alteration (≥150 sf) or adding/altering fences, retaining walls, parking or yard infrastructure, expect Design Review and bring a landscape plan that shows existing significant trees, replacement plantings, irrigation and maintenance commitments (§ 20.66.020; master/precise plan lists).
• For new fences: measure from finished grade; if the fence is within the 4/7‑ft thresholds and entirely on private property outside special ROW locations, you usually do not need a fence permit — but if the fence faces the street, is in the ROW, or exceeds the threshold, apply for a Fence Permit and be prepared to address sight‑lines, pedestrian access, parking impacts, and animal movement findings (Chapter 20.60).
• For tree removals tied to development: plan for a tree protection plan prepared by an arborist where proposed work is near protected or heritage trees; the code authorizes required replacement (including a 1:1 minimum and a stricter formula for heritage trees) and lets the City attach conditions and penalties for non‑compliance (§ 20.67.050 et seq.; § 20.67.150).
• For utility screening and transformers: show required clearances and plan planting or low decorative walls that meet both utility safety clearances and the City’s landscape screening expectation — these are treated as part of the site’s landscape/screening design under Design Review.

Checklist — what an applicant must satisfy (quick)

• Determine whether your project triggers Design Review (≥150 sf exterior change or physical improvements); if so, prepare design‑review submittal (§ 20.66.020).
• Prepare a landscape plan (existing trees with spread, trees to be removed, planting list, irrigation, maintenance) for master/precise plan or design review submittal; show lot coverage and relationship to setbacks.
• If removing trees, prepare a tree protection/removal package and plan for replacement per code (heritage tree formula or 1:1 at minimum). (§ 20.67.x)
• If building a fence: measure height from finished grade; confirm if it fits the 4 ft (exterior) / 7 ft (interior) no‑permit thresholds — otherwise submit a Fence Permit and address the required findings (Chapter 20.60).
• For screening mechanicals, transformers, trash enclosures or parking: include integrated screening details (materials, species, clearances) on the landscape plan and note maintenance obligations.
• If your site is in a PD, R‑P, or an overlay, confirm overlay‑specific landscape or open‑space conditions and include any required scenic easements or undisturbed areas if imposed.
• Verify whether sidewalk/ROW encroachment requires an encroachment permit from Public Works in addition to any Fence Permit for ROW fences (Chapter 11.16 referenced by the fence findings).

Risks & Ambiguities

Plain‑English summary

If your Mill Valley project changes the exterior (including fences, retaining walls, parking areas, transformer enclosures or removes protected trees), plan on Design Review or specific permits: bring a landscape plan showing existing and replacement trees, use the City’s fence height thresholds (4 ft front / 7 ft interior) as a baseline, and expect tree‑replacement and maintenance conditions; always verify ROW and overlay rules with Planning & Building.

Source References

• Chapter 20.12 — Districts Generally (§ 20.12.010 – § 20.12.040).
• Chapter 20.08 — Definitions; accessory structure and height measurement (see § 20.08.050 for measurement rules).
• Chapter 20.60 — General Provisions and Exceptions (fencing controls; Chapter range § 20.60.060 – § 20.60.300 includes the Fence Permit rules and findings).
• Chapter 20.66 — Design Review (triggers, findings, exemptions; see § 20.66.020, § 20.66.030, § 20.66.045).
• Chapter 20.18 — R‑P Districts / Planned Residential (master plan, precise development and required landscape plan content; § 20.18.010 – § 20.18.110).
• Chapter 20.67 — Trees (tree permit, heritage tree rules, replacement requirements; see § 20.67.150 and related tree sections).
• Chapter 20.68 — Enforcement, penalties and procedure (§ 20.68.010 – § 20.68.060).
• Multi‑family district examples and development standards (RM‑3.5 example including lot coverage, setbacks and heights).
• Utility/transformer and wireless facility screening and landscaping expectations (development standards and accessory equipment screening).

If you want the exact code printout lines or help locating the single page/section where the Fence Permit is codified (the file preview contains the language but the PDF section header numbering is presented across the chapter), I can extract the precise section number and the authoritative Mill Valley Municipal Code URL for you — tell me whether you prefer a direct city‑code URL or a compiled PDF view and I’ll fetch it (Verify with the jurisdiction).

Retrieved passages

• Mill Valley Zoning Code (Section 20.66.045.) High relevance show source text
• Mill Valley Zoning Code (Section 20.20.070.) High relevance show source text
• Mill Valley Zoning Code (§ 2) High relevance show source text
• CWUIC § 65850.6 (Title 24) High relevance show source text
• California Building Code High relevance show source text
• Mill Valley Zoning Code (§ 2) Medium relevance show source text
• Mill Valley Zoning Code (§ 9) Medium relevance show source text
• Mill Valley Zoning Code (Section 20.66.045.) Medium relevance show source text
• Mill Valley Zoning Code (section of) Medium relevance show source text
• Mill Valley Zoning Code (Chapter 11.16) Medium relevance show source text
• Mill Valley Zoning Code (Section 20.20.070.) Medium relevance show source text
• Mill Valley Zoning Code (Chapter 11.16) Medium relevance show source text
• Mill Valley Zoning Code (Section 20.26.040) Medium relevance show source text
• Mill Valley Zoning Code (§ 2) Medium relevance show source text
• Mill Valley Zoning Code (Chapter 20.100.) Medium relevance show source text
• Mill Valley Zoning Code (§ 2) Medium relevance show source text
• Mill Valley Zoning Code (§ 6) Medium relevance show source text
• Mill Valley Zoning Code (Section 20.64.100.) Medium relevance show source text

Cited sections

• Chapter 20.12 — Districts Generally (§ 20.12.010 – § 20.12.040). (Chapter 20.12)
• Chapter 20.08 — Definitions; accessory structure and height measurement (see § 20.08.050 for measurement rules). (Chapter 20.08)
• Chapter 20.60 — General Provisions and Exceptions (fencing controls; Chapter range **§ 20.60.060 – § 20.60.300** includes the Fence Permit rules and findings). (Chapter 20.60)
• Chapter 20.66 — Design Review (triggers, findings, exemptions; see **§ 20.66.020**, **§ 20.66.030**, **§ 20.66.045**). (Chapter 20.66)
• Chapter 20.18 — R‑P Districts / Planned Residential (master plan, precise development and required landscape plan content; § 20.18.010 – § 20.18.110). (Chapter 20.18)
• Chapter 20.67 — Trees (tree permit, heritage tree rules, replacement requirements; see **§ 20.67.150** and related tree sections). (Chapter 20.67)
• Chapter 20.68 — Enforcement, penalties and procedure (§ 20.68.010 – § 20.68.060). (Chapter 20.68)
• Multi‑family district examples and development standards (RM‑3.5 example including lot coverage, setbacks and heights).
• Utility/transformer and wireless facility screening and landscaping expectations (development standards and accessory equipment screening).
• MillValley_ZoningCode.md
• 2022 PGE Greenbook.md
• 2025 California Wildland-Urban Interface Code.md

• Official Mill Valley code library