Imperial County — Design Review

Last reviewed: July 6, 2026

Overview

In unincorporated Imperial County, “design review” is carried out through a combination of the County’s Architectural Design Combining Zone, required plot plan and site plan submissions, and zone-specific development standards under the County’s Land Use Ordinance. The process is not a separate “citywide” program; it applies only where the code requires it in unincorporated areas and, in some overlays, before specific types of development. See the broader context in the County’s zoning overview and base zoning.

The single biggest design rule: if your parcel is in the County’s “D” Architectural Design Zone, exterior architecture, site, sign, and landscaping plans must be reviewed and approved for visual compatibility before you build, alter, or repaint a structure in the unincorporated areas (see § 90501.07).

What counts as “Design Review” in Imperial County

• Architectural Design Zone review in the D overlay: submittal and approval of exterior design, site, sign, and landscaping plans; appeals go up to the Planning Commission and then to the Board of Supervisors (§ 90501.07).
• Site Plan Review in the MU Mixed‑Use Overlay (on C‑1/C‑2 parcels): new development requires a site plan review permit with findings; pre‑application is encouraged (§ 90501.11.B).
• Plot Plan Review for permitted uses/developments: before establishing a permitted use, a plot plan must be submitted and approved; application contents include circulation/parking, landscaping, lighting, and fire access (§ 90301.03 and preceding paragraph).
• Countywide site plan package for land use permits (ministerial): includes a site plan with a parking plan and a landscaping and screening plan per cross‑referenced sections, with 30‑day completeness review and stated timelines (§§ 90405.09–90405.10).

Decision‑relevant standards and who reviews

Also remember: sign plans are part of design submittals in the D zone; see related signage controls referenced by the design chapter (§ 90501.07.C.3).

District-by-district design review touchpoints (unincorporated areas)

D — Architectural Design Zone (combining/overlay)

• Purpose: Ensure buildings, signs, site, and landscaping are “harmonious” and not unsightly; protect area appearance (§ 90501.07.A).
• Typical permitted uses: Those of the underlying base zone; the D overlay adds design‑review control (Not found in retrieved materials).
• Key dimensional standards: The overlay emphasizes qualitative criteria (height/bulk relationship, setbacks, colors/materials, roof pitch, fenestration, signs, lighting, and neighborhood compatibility) (§ 90501.07.A.1–11).
• Where it applies: Wherever mapped with the “D” overlay. Verify on the County zoning map (Verify with the jurisdiction).

MU — Mixed‑Use Overlay (on C‑1/C‑2)

• Purpose: Encourage integrated residential and commercial in one site or group of parcels; pedestrian‑oriented design; discourage single‑use projects (§ 90501.11.A).
• Typical permitted uses: A wide range that mixes housing and compatible non‑residential uses (broadly described; specifics Not found in retrieved materials).
• Key procedural standard: New development requires a site plan review permit; pre‑application is encouraged (§ 90501.11.B).
• Where it applies: Only where the MU overlay has been applied to C‑1/C‑2 parcels.

U — Urban Areas Overlay

• Purpose: Identify lands within an urban area of an incorporated city or County‑designated urban area; the County’s intent is to adhere to the standards of that urban jurisdiction (§ 90501.08).
• Practical effect: Design review may follow the applicable city’s rules in these mapped County overlays (Verify with the jurisdiction).
• Where it applies: Only where the U overlay is mapped over a base zone.

Commercial Zones — C‑0, C‑1, C‑2, C‑3

• Design‑related standards: Provide required right‑of‑way dedications/improvements; shield exterior lighting; screen trash; ensure architectural compatibility with surroundings (§ 90301.02; and items K–M).
• Adjacent to single‑family residential: Provide a 6 ft masonry wall, reduced to 3 ft within the front setback (§ 90301.02.J).
• Where it applies: Where the County zoning map designates commercial zones; many projects still require plot plan or site plan packages before permitting (§§ 90301.03; 90405.09).

Industrial Zones — M‑1, M‑2, M‑3

• Design‑related standards: Similar to commercial for lighting/trash/walls/compatibility, plus dust control binders for outdoor storage and fugitive dust during grading (§ 90301.02.N–O).
• Where it applies: Industrially zoned parcels; plot plan review and commercial/industrial development standards apply (§ 90301.02; 90301.03).

Residential Zones — R‑1, R‑2, R‑3, R‑4

• Design‑related standards: Shield lighting; screen trash; ensure architectural compatibility; where a residential project abuts non‑residential, construct a 6 ft wall (reduced to 30 in in the front setback) (§ 90301.01.J–M).
• Larger projects: With 10+ dwellings, set aside at least 5% of net parcel area (minimum 400 sq ft per location) as usable open space (§ 90301.01.N).
• Where it applies: All residential zones; plot plan/site plan content requirements still apply for many developments (§§ 90301.03; 90405.09).

Process and submittals that shape design outcomes

• Site plan package for land use review: Must show boundaries, structures, distances, access, utilities, parking, landscaping, drainage, and more; the Department may reject incomplete/illegible plans (§ 90405.09). This package undergoes a 30‑day completeness check; completed applications are reviewed for consistency with the General Plan and Land Use Ordinance (§ 90405.10).
• Plot plan review: Before most permitted uses are established, submit a plot plan package with circulation/parking, parking layout, landscaping and screening, lighting, and fire access details (§ 90301.03).
• D‑zone architectural submittals: Exterior design/elevations, plot plan, sign and parking plans are reviewed for harmony with area character; staff may confer with applicants to revise plans; formal appeals are available (§ 90501.07.C).
• MU site plan review: New development within MU requires a site plan review permit; pre‑application is encouraged to address compatibility and pedestrian design early (§ 90501.11.B).
• Fees: County Design Review fees are published (e.g., Residential base $600; Commercial <20,000 sf $1,500; >20,000 sf $2,000) at application intake (County fee schedule).

Related topics you may need: Imperial County Development Standards, Imperial County Overlay Districts, Imperial County Nonconforming Uses, Imperial County Variances and Exceptions, and if a building permit is required, the California Building Standards Code. For housing approvals with state timelines, see California ADU law (note the ADU timeline reference in § 90405.10).

Checklist

• Confirm base zoning and overlays (including D, MU, U) for the parcel in unincorporated Imperial County; coordinate early if the U overlay references an incorporated city’s standards (§ 90501.08).
• If in the D zone, compile exterior elevations, materials/colors, roof details, sign plan, plot plan, parking, and landscaping for design approval (§ 90501.07.C).
• If in the MU overlay, schedule a pre‑application conference and prepare a site plan review permit package (§ 90501.11.B).
• For most permitted uses, prepare a complete plot plan review application with circulation/parking, fire access, landscaping, and lighting details (§ 90301.03).
• Provide a complete site plan for land use review with drainage, utilities, and all required plan details; allow for the 30‑day completeness review window (§§ 90405.09–90405.10).
• Design to meet development standards that function like design conditions: screening of trash, shielding of lighting, compatibility of building design, required walls where uses abut (§§ 90301.01–90301.02).
• Pay Design Review fees per the County’s current fee schedule (Design Review).
• If you need relief from a standard, consider a variance or exception; if your site is nonconforming, review nonconforming use rules (Verify with the jurisdiction).

Risks & Ambiguities

Plain-English Summary

If you build in unincorporated Imperial County, you’ll typically submit a plot plan and site plan showing layout, parking, and landscaping. In “D” design overlay areas, your exterior architecture and signs must be approved for visual compatibility; in the MU overlay on C‑1/C‑2 sites, a site plan review permit is required. Plan for walls where homes abut commercial/industrial, shield lights, screen trash, and design buildings to fit neighborhood character—all checked during County review.

Information Gaps

• Where the “D” overlay is mapped and whether any design handbooks or guidelines supplement § 90501.07 (Not found in retrieved materials).
• Specific permitted uses and dimensional standards by base zone for purposes of design review context (Not found in retrieved materials).
• Detailed parking and landscaping standards cross‑referenced from the site plan section (§§ 90302.00, 90402.00) (Not found in retrieved materials).

Source References

• § 90501.07 Architectural Design Standards (D zone) — County of Imperial Codified Ordinances (Land Use Ordinance).
• § 90501.11 Mixed‑Use Overlay — Site plan review permit requirement.
• § 90501.08 U (Urban Areas) Overlay — Adherence to urban jurisdiction standards.
• § 90301.01 Development standards (residential) — walls, lighting, trash, compatibility, open space.
• § 90301.02 Development standards (commercial/industrial) — dedications, lighting, trash, compatibility.
• § 90301.03 Plot plan review — application content.
• §§ 90405.09–90405.10 Land use/site plan review — site plan contents; 30‑day completeness; timelines.
• County Design Review Fees — Planning & Development Services fee schedule (Design Review).

Retrieved passages

• Imperial County Zoning Code (§ 1) Medium relevance show source text
• Imperial County Zoning Code (§ 3) Medium relevance show source text
• Imperial County Zoning Code (§ 3) Medium relevance show source text
• Imperial County Zoning Code (§ 3) Medium relevance show source text
• Imperial County Zoning Code Medium relevance show source text
• Imperial County Zoning Code (title until) Medium relevance show source text
• Imperial County Zoning Code (chapter is) Medium relevance show source text
• Imperial County Zoning Code (§ 70) Medium relevance show source text

Cited sections

• § 90501.07 Architectural Design Standards (D zone) — County of Imperial Codified Ordinances (Land Use Ordinance). (§ 90501.07)
• § 90501.11 Mixed‑Use Overlay — Site plan review permit requirement. (§ 90501.11)
• § 90501.08 U (Urban Areas) Overlay — Adherence to urban jurisdiction standards. (§ 90501.08)
• § 90301.01 Development standards (residential) — walls, lighting, trash, compatibility, open space. (§ 90301.01)
• § 90301.02 Development standards (commercial/industrial) — dedications, lighting, trash, compatibility. (§ 90301.02)
• § 90301.03 Plot plan review — application content. (§ 90301.03)
• §§ 90405.09–90405.10 Land use/site plan review — site plan contents; 30‑day completeness; timelines. (§ 90405.09)
• County Design Review Fees — Planning & Development Services fee schedule (Design Review).
• ImperialCounty_ZoningCode.md

• Official Imperial County code library