Walnut — Design Review

Last reviewed: July 3, 2026

Overview

Walnut handles design review through a citywide Site Plan and Architectural Review chapter (Chapter 6.84) plus zone-specific triggers and standards in several chapters (residential, mixed‑use overlays, public institution, specific plans). The basic rule: no building or use permit for construction, alteration or addition is to be issued until site plan and architectural approval is obtained, subject to limited Director approvals for small residential additions (§ 6.84.020).

This reference explains what the Walnut Municipal Code actually requires for design review, where design review is mandatory, how projects are evaluated, and the practical implications for applicants (district‑by‑district and citation‑grounded).

What the code says (core rules and review process)

• Site plan and architectural review is created to promote orderly development and preserve architectural character — Chapter 6.84 and § 6.84.010.
• The mandatory trigger: “No building or use permit shall be issued … until site plan and architectural approval have been obtained from the Planning Commission” except where the Community Development Director is specifically authorized to act (see limited Director authority) (§ 6.84.020).
• Application contents are specified (name, ownership, legal description, full site plan showing buildings, yards, driveways, parking, landscaping, architectural renderings, etc.) (§ 6.84.040).
• Approval basis: the Planning Commission must make findings on design compatibility, materials, massing, roof lines, viewshed, landscaping, and public welfare (detailed criteria are listed) (§ 6.84.050).
• Commission actions: approve, approve with conditions, or deny. Applicant notification and appeal procedures are provided (decision notice within 10 days; appeals to City Council) (§§ 6.84.060–6.84.080).

Practical linkbacks (first natural mentions):

• The city’s base rules interact with the Walnut Development Standards for setbacks, lot coverage and height; those numeric standards show up in each zone chapter.
• Projects involving parking or parking reductions tie to the Walnut Parking rules and (where relevant) density‑bonus parking concessions.
• Mixed‑use and housing priority areas layer on requirements; see Walnut Overlay Districts.
• ADU applications reference both ADU-specific development limits and design review interactions; see Walnut ADUs.
• Historic properties get additional review under the Walnut Historic Preservation chapter when design changes affect designated resources.
• Landscaping and screening expectations referenced in review criteria are implemented under Walnut Landscaping and Screening.
• Some technical compliance (structural, life‑safety) remains in the California Building Standards Code, not the zoning/design review chapters.

District‑by‑district breakdown (where design review applies and key numeric standards)

NOTE: Each district subsection below lists purpose, typical permitted uses, the design‑review trigger(s) and the key dimensional standards the code uses as the frame for design review findings. All statements cite the controlling Walnut Municipal Code sections that were retrieved.

R-1 (Single‑Family Residential) — Chapter 6.12

• Purpose / typical uses: single‑family detached homes and accessory uses (garages, patios, accessory buildings). Permitted uses and dimension rules are under Chapter 6.12.
• Design review trigger: Site plan and architectural review is required for construction/alteration unless the Director can approve limited residential additions under Chapter 6.84 (§ 6.84.020).
• Key dimensional standards used in review:
  • Front yard setbacks: 20 ft (standard single‑family under 4,500 sq ft living area) or 30 ft for homes ≥ 4,500 sq ft (§ 6.12.040—yards).
  • Height limits: dwelling units no more than two stories or 35 ft; accessory buildings 1 story or 17 ft (building bulk rules).
  • Maximum lot coverage: 40% (R‑1) — relevant for ADU and lot‑coverage review (ADU limits and R‑1 lot coverage).
• Where it applies: across single‑family neighborhoods; the Commission (or Director for small additions) evaluates compatibility with adjacent houses, landscaping and viewshed (§ 6.84.050).

R-3 (Multiple‑Family Residential) — Chapter 6.32

• Purpose / typical uses: multifamily units (apartments, condos) with minimum lot area and density and unit size standards.
• Design review trigger: Multifamily developments (new construction or redevelopment) are evaluated through site plan and architectural review; specific plan developments may provide objective standards to apply (see MU/HOO specific plan links). (§ 6.84.020; § 6.20.070).
• Key dimensional standards used in review:
  • Front yard: 20 ft (R‑3) (§ 6.32.060).
  • Max building height: generally two stories / 35 ft for primary buildings (see R‑3 chapter).
  • Lot coverage (R‑3): 60% (used as an objective cap when assessing massing) (ADU/coverage table).

RPD (Residential Planned Development) — Chapter 6.24

• Purpose / typical uses: flexible planned development to achieve better site design, preserve open space and provide design flexibility. (§ 6.24.010–.020).
• Design review trigger: RPDs are subject to the development review/Planning Commission and development review board procedures; site plans and architecture are central to approval.
• Key standards used in review:
  • Density and minimum net acre density set at rezoning time; lot size designations (e.g., RPD (10,000)—3.5) and other dimensional rules are imposed at zoning action.
  • Open space requirements: minimum 20% of gross area for RPD developments (used in Commission findings).

MU/HOO (Mixed‑Use / Housing Opportunity Overlay) — Chapter 6.20

• Purpose / typical uses: targeted overlay to encourage higher‑density and affordable housing coupled with integrated commercial uses. Applicable to three mapped areas MU/HOO‑1, MU/HOO‑2, MU/HOO‑3 (§ 6.20.010–.020).
• Design review trigger: All proposed development and new construction that results in change of land use within MU/HOO must undergo site plan and architectural review as prescribed in Chapter 6.84; project processing may be concurrent with other entitlements (§ 6.20.070).
• Key dimensional considerations used in review:
  • Specific plans generally establish the objective standards (setbacks, heights, parking ratios). If a specific plan applies, that plan’s standards prevail over the base zone (§ 6.20.050–.080).
  • Lot coverage in MU/HOO varies by specific plan district (up to 80% in some MU/HOO‑1 rules) — check the applicable specific plan.

School & Public Institution Zone (Civic/Institutional) — Chapter 6.50

• Purpose / typical uses: schools, public institutions and related facilities. (§ 6.50.010 et seq.).
• Design review trigger: All development in the school and public institution zone must be submitted for site plan and architectural review by the Planning Commission (explicit requirement) (§ 6.50.060(A)).
• Key numeric standards used in review:
  • Building height: up to 3 stories and 35 ft (with Planning Commission ability to approve increased height upon findings) (§ 6.50.060(B)).
  • Setbacks: minimum 20 ft from public right‑of‑way, 10 ft from interior property lines; larger separations required when abutting residential zones for parking facilities (§ 6.50.060(D)).

Quick standards & uses table (decision‑relevant)

Practical guidance (how to approach a Walnut design review application)

• Prepare full‑package site plans and high‑quality architectural renderings; the code specifically requires renderings and calls out façade articulation, materials and colors in the approval criteria (§ 6.84.040–6.84.050).
• If your project is a small residential addition, consider the Director approval path only if the addition is ≤ 50% of existing living area and ≤ 2,000 sq ft including garage (§ 6.84.020(B)); otherwise expect Planning Commission review.
• If in a Mixed‑Use Overlay or a Specific Plan area, obtain the applicable specific plan and verify which objective design standards apply; specific plan standards override base zone in case of conflict (§ 6.20.050–.080).
• For ADUs, review the ADU chapter for setbacks (e.g. 20 ft front for R‑1), minimum side/rear setbacks (4 ft), FAR and lot coverage caps that affect what can be built without discretionary deviations (ADU sections).
• Landscaping, screening of equipment, and protection of viewsheds are explicit review considerations — include a landscape plan and screening details up front (§ 6.84.050(K–M); § 6.50.060(E–F)).

Checklist (what an applicant must submit / satisfy)

• Completed site plan & architectural review application with signatures and ownership documentation (per § 6.84.040)
• Scaled site plan showing building footprints, yards/setbacks, driveways, parking layout, circulation and trash/utility locations (§ 6.84.040)
• Architectural elevations/renderings and materials/colors schedule (façade articulation and rooflines are explicit review criteria) (§ 6.84.050)
• Landscape and screening plan (plant palette, irrigation, and screening for roof/equipment) (§ 6.84.050(K–M); § 6.50.060(E))
• Parking calculations and justification (including ADU parking exceptions where applicable) (ADU parking rules and Chapter 6.68 / density bonus parking rules)
• If in a specific plan or overlay, documentation showing compliance with that plan’s objective standards (§ 6.20.050–.070)
• Fee payment and any special studies requested by the Community Development Director (e.g., traffic, tree report, co‑location justification for antennas) (various chapters; see filing fee rules)

Risks & Ambiguities

Information Gaps (items not found or not explicit in retrieved materials)

• A fixed processing time for Planning Commission action on a standard site plan & architectural review (no explicit statutory deadline in Chapter 6.84 beyond notice procedures). Not found in retrieved materials; verify current typical timelines with staff.
• Detailed submittal checklist with exact sheet counts, file formats, or electronic plan submittal requirements — Chapter 6.84.030–.040 lists content but not file/format requirements. Not found in retrieved materials; check Planning Department submittal instructions.
• Any separate “Design Review Board” with independent authority — Walnut uses the Planning Commission and Community Development Director for site plan & architectural review as described; a separate DRB is not shown in retrieved materials.

Plain‑English summary

If you want to build, enlarge, or change the exterior of a building in Walnut, you normally must submit a site plan and architectural review package and get approval before a building permit is issued; small residential additions (under 50% growth and ≤ 2,000 sq ft) can sometimes be approved by staff, but larger or new projects go to the Planning Commission and are judged against specific design criteria (compatibility, massing, materials, landscaping, screening and views) (§§ 6.84.020, 6.84.040–6.84.050).

Source References

• Walnut Municipal Code, Chapter 6.84 (Site Plan and Architectural Review) — §§ 6.84.010–6.84.090 (core review rules, application contents, approval criteria, notice, appeals).
• Walnut Municipal Code, Chapter 6.20 (Mixed‑Use / Housing Opportunity Overlay Zone) — §§ 6.20.010–6.20.070 (MU/HOO applicability; site plan review requirement) § 6.20.070.
• Walnut Municipal Code, Chapter 6.12 (R‑1 Single‑Family) — yard, bulk, lot dimensions and setbacks (R‑1 standards).
• Walnut Municipal Code, Chapter 6.32 (R‑3 Multiple‑Family) — unit sizes, yard regs and height limits.
• Walnut Municipal Code, Chapter 6.24 (RPD Residential Planned Development) — intent and plan/design controls.
• Walnut Municipal Code, Chapter 6.50 (School & Public Institution zone) — explicit site plan review mandate and setbacks (§ 6.50.060).
• Walnut Municipal Code, ADU provisions (setbacks, lot coverage, FAR, parking exceptions) — ADU development standards and how they interface with design review.
• Walnut Municipal Code, Chapter 6.104 (Historical Preservation) — plan review and register for historic resources.

Retrieved passages

• Walnut Zoning Code (§ 6.84.030.) High relevance show source text
• Walnut Zoning Code (§ 6.84.050.) High relevance show source text
• Walnut Zoning Code (§ 6.20.080.) Medium relevance show source text
• Walnut Zoning Code (§ 6.84.060.) Medium relevance show source text
• Walnut Zoning Code (§ 6.20.040.) Medium relevance show source text
• Walnut Zoning Code (§ 6.32.040.) Medium relevance show source text
• CBC § 6.88.050 (§ 6.88.050.) Medium relevance show source text
• Walnut Zoning Code Medium relevance show source text
• Walnut Zoning Code (§ 6.50.050.) Medium relevance show source text
• Walnut Zoning Code Medium relevance show source text
• Walnut Zoning Code Medium relevance show source text
• Walnut Zoning Code (§ 6.08.060.) Medium relevance show source text
• Walnut Zoning Code Medium relevance show source text
• Walnut Zoning Code (§ 1) Medium relevance show source text
• Walnut Zoning Code (chapter not) High relevance show source text
• Walnut Zoning Code Medium relevance show source text
• Walnut Zoning Code (§ 6.16.040.) Medium relevance show source text

Cited sections

• Walnut Municipal Code, Chapter **6.84** (Site Plan and Architectural Review) — **§§ 6.84.010–6.84.090** (core review rules, application contents, approval criteria, notice, appeals). (§ 6.84.010)
• Walnut Municipal Code, Chapter **6.20** (Mixed‑Use / Housing Opportunity Overlay Zone) — **§§ 6.20.010–6.20.070** (MU/HOO applicability; site plan review requirement) **§ 6.20.070**. (§ 6.20.010)
• Walnut Municipal Code, Chapter **6.12** (R‑1 Single‑Family) — yard, bulk, lot dimensions and setbacks **(R‑1 standards)**.
• Walnut Municipal Code, Chapter **6.32** (R‑3 Multiple‑Family) — unit sizes, yard regs and height limits.
• Walnut Municipal Code, Chapter **6.24** (RPD Residential Planned Development) — intent and plan/design controls.
• Walnut Municipal Code, Chapter **6.50** (School & Public Institution zone) — explicit site plan review mandate and setbacks **(§ 6.50.060)**. (§ 6.50.060)
• Walnut Municipal Code, ADU provisions (setbacks, lot coverage, FAR, parking exceptions) — ADU development standards and how they interface with design review.
• Walnut Municipal Code, Chapter **6.104** (Historical Preservation) — plan review and register for historic resources.
• Walnut_ZoningCode.md

• Official Walnut code library