Local zoning · Humboldt County

Humboldt County — Design Review

Q: Do I need design review in unincorporated Humboldt County?

If your parcel is mapped with the D (Design Control) combining zone, then yes: development on those parcels is subject to the D Zone design‑review process and a special permit is required; solar collectors for on‑site use are explicitly exempt. § 19.1.2; § 19.1.3.1–.2

Design Review under the Humboldt County local zoning and planning code, with the controlling citations.

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Last reviewed: July 3, 2026

Overview

Design review in unincorporated Humboldt County is implemented through the Design Control Combining Zone (D Zone) and related sub-area design-review rules. The D Zone is a combining (overlay) tool applied to parcels to ensure new development conforms to the General Plan and preserves identified historical, scenic, cultural or architectural values; the rules require a discretionary permit and a design-oriented review of site plans, building form, materials and landscaping. See the County Zoning rules on design review for the unincorporated areas in the County’s zoning code (the local “design review” program is administered inside the County zoning framework). § 19.1.1

(Links: this page mentions the County’s design review program and interacts with parking, setbacks and other development standards, overlay districts, historic preservation, signage, landscaping and screening, and the California Building Standards Code.)

How Humboldt’s Design Review is organized (district-by-district)

Design review in Humboldt County is not a single “one-size” chapter that replaces underlying zoning — it is a combining zone and several area-based procedures. Below are the distinct, code-defined “districts” or area-specific design-review systems and what each controls in the unincorporated areas.

D Zone (Design Control Combining Zone)

Purpose: The D Zone preserves and enhances areas of historic, scenic, civic or cultural value and to ensure appearance and design of buildings, sites, structures and signs contribute to the desirability of the area. § 19.1 D (intro) and § 19.1.1
Typical permitted uses: Uses remain those of the underlying principal zone; the D Zone is a combining overlay applied to existing zones and does not itself change use permissions. Verify with the Planning Division whether a parcel is mapped D. § 19.1 D (intro)
Key design/dimensional standards the reviewing authority considers: height, bulk and area of buildings; all setbacks; exterior colors, textures and materials; roof type/pitch/material; sign location/size/type; landscaping and parking layout; relationship to nearby buildings; historic architectural treatment; grading/cut-and-fill and preservation of trees. These are the explicit review criteria. § 19.1.3.1–19.1.3.9
Where it applies: To lands designated “D” on the County Zoning Maps; solar collectors for on‑site use are specifically exempt from the D Zone review requirement. § 19.1.2

Samoa design-review program (Samoa Design Review Committee / Samoa D Zone)

Purpose: Additional historic-preservation and design controls for the Samoa town/marina area as part of the Humboldt Bay Area Plan. § 19.1.4.1 (Samoa DRC authority) and §§ 19.1.9.* (Samoa standards)
Typical permitted uses: Underlying zoning determines uses; the Samoa DRC focuses on alterations/demolitions and compatibility with contributing historic structures. § 19.1.4.1.1.1–.1.2 and § 19.1.9.1.3
Key standards and special rules: No contributing historic structure shall be altered without County approval; demolition of contributing structures is subject to specific findings and may be delayed or conditioned; reviews are to be based on the Secretary of the Interior’s Standards, Department of Interior rehabilitation standards, State historic building code and the Samoa Design Guidelines. § 19.1.9.1.1–1.3 and § 19.1.4.1.2.1–.2.1
Where it applies: Samoa portions of the Humboldt Bay Area Plan and areas specifically mapped as Samoa D controls. § 19.1.9.*

Scotia design-review program (Scotia DRC / Scotia-specific rules)

Purpose: Protect Scotia’s historic townsite and guide alterations, demolition and compatible new development. § 19.1.9.3 (Scotia)
Typical permitted uses: Underlying zone uses, with historic resources treated as subject to design/historic review. § 19.1.9.3.1.1–3.2
Key standards and special rules: If a Scotia DRC is not appointed, the Director requires a Historic Assessment Study prepared by a qualified consultant; alterations/demolitions are reviewed under Secretary of the Interior guidelines and Scotia Design Guidelines. § 19.1.9.3.2–3.3
Where it applies: Scotia plan area parcels mapped to the Scotia design-control overlay. § 19.1.9.3.*

Shelter Cove additional standards (Shelter Cove D-subarea)

Purpose/intent: Ensure new residential development is compatible with existing Shelter Cove character. § 19.1.4 (Shelter Cove additional standards)
Typical permitted uses: Underlying zone uses; design rules apply to developments within the Shelter Cove portions of the D overlay. § 19.1.4.*
Key dimensional / construction standards (examples you must meet in Shelter Cove design review):
- Residences must be constructed to a minimum width of twenty (20) feet at the narrowest point. § 19.1.4.1.1.1
- Foundations meeting seismic Zone IV continuous perimeter foundation requirements (exceptions for engineered pole structures where perimeter foundation not feasible). § 19.1.4.1.1.2
- Minimum roof overhang of twelve (12) inches required on residences (gable exceptions possible via design review). § 19.1.4.1.1.3
- Exterior walls and roofing of unfinished/galvanized metal are prohibited; metal finishes must carry a minimum 15‑year warranty; flammable roofing not recommended. § 19.1.4.1.1.4
Where it applies: Shelter Cove parcels mapped to the Shelter Cove sub-area of the D overlay. § 19.1.4.*

Telecommunications / Wireless Facilities design review

Purpose: Site-specific design review requirements for wireless telecom facilities that require design review are set out in the wireless facilities chapter and include detailed submittal requirements such as notice, visual impact and alternatives analysis. § 91.2.8.3 and subparts
Key requirements: Applicants for Tier 2/3 facilities must include a design-review checklist, provide notice to all landowners/residents within 300 feet sent within ten days before application, complete an alternatives analysis, and provide visual impact analysis including photo simulations or balloon tests and landscaping plans. § 91.2.8.3.1–.3.4
Where it applies: County-wide rules for wireless facilities sited in unincorporated areas; the telecom design-review process overlays other zoning and environmental requirements. § 91.2.8.*

Quick reference table — decision‑relevant standards and uses

Issue / Standard	What the code requires (summary)	Code Reference
Applicability — D Zone	Applies where zoning maps show D; solar collectors for on‑site use are exempt.	§ 19.1.2
Permit required	Special Permit required for development subject to D regulations; fee per Board schedule.	§ 19.1.3.1 / § 19.1.3.2
Architectural review criteria	Review authority must consider height, bulk, setbacks, materials, roof, signs, landscaping/parking layout, relationship to nearby buildings, historic treatment, grading/tree preservation.	§ 19.1.3.1–.9
Samoa — demolition/alteration	No contributing historic structure may be altered/demolished without approval; demolition subject to specific findings; Secretary of Interior standards apply.	§§ 19.1.4.1.1 / 19.1.9.1.1–1.3
Scotia — historic assessment	If no Scotia DRC, Director requires a Historic Assessment Study prepared by qualified consultant.	§ 19.1.9.3.2.1–.2.2
Shelter Cove — residential design	Min width 20 ft, perimeter foundation meeting seismic Zone IV, 12" roof overhang, no unfinished metal siding/roof.	§ 19.1.4.1.1.1–.1.4
Telecom design review — submittals	Tier 2/3 design review needs checklist, 300‑ft notice, alternatives analysis, visual impact/photographic simulations.	§ 91.2.8.3.1–.3.4

Procedure & what the reviewer looks at (practical guidance)

The reviewing authority is a Board‑appointed committee for a D Zone or, if none is appointed, the Planning Director or the member of the Board of Supervisors for that district acts as reviewing authority. Local representatives are given preference; committees normally do not exceed five members. § 19.1.2; § 19.1.4
Applications for development in a D Zone must submit the data required by the ordinance and pay the application fee. Applicants should anticipate plan sets showing site layout, floor plans, elevations, materials/finishes, landscaping and parking plans, grading/trees, and sign details. § 19.1.5.1; § 19.1.3.6
For historic areas (Samoa, Scotia), expect additional submittals: documentation of historic status, Secretary of the Interior compliance narrative, and, when the DRC is not in place, a professional Historic Assessment Study. §§ 19.1.4.1.2.1; 19.1.9.3.2.1–.2.2
For telecom projects, provide visual simulations (photo‑montages or balloon tests), an alternatives analysis, and evidence of pre‑application mailing to property owners within 300 feet. § 91.2.8.3.*

Checklist

Confirm whether the parcel is mapped D (Design Control Combining Zone); if yes, confirm which sub‑area (Samoa, Scotia, Shelter Cove). Verify with the jurisdiction. § 19.1.2
Completed special‑permit / design‑review application and payment of the fee (fee set by Board). § 19.1.3.2 / § 19.1.5.1
Full plan set: site plan, grading plan, floor plans, building elevations, materials/finishes, color palette, roof details. § 19.1.3.1–.5
Landscaping plan and parking layout consistent with design findings. § 19.1.3.6; link to parking and landscaping and screening.
Signage details (type, size, location). § 19.1.3.5; link to signage.
If project is in Samoa or Scotia or affects a potentially contributing historic resource, include historic documentation or a Historic Assessment Study (if DRC is not appointed) and Secretary of the Interior Standards analysis. §§ 19.1.4.1.2.1; 19.1.9.3.2.1–.2.2
For Shelter Cove: demonstrate compliance with Shelter Cove building/design standards (min 20 ft width, foundation, 12" overhang, materials warranty). § 19.1.4.1.1.1–.1.4
For wireless telecom: include design checklist, alternatives analysis, visual impact analysis (photo simulations or balloon test), and proof of 300‑ft notice to neighbors. § 91.2.8.3.*

Risks & Ambiguities

Issue	Why it matters	What to verify
Is the parcel actually mapped D?	Design review rules apply only where D is shown; unnecessary submittals waste time/cost.	Confirm zoning map / D overlay status with Planning Division (not explicit in application packets). § 19.1.2
Is a local DRC appointed?	If no DRC exists, the Director or Board member may act or require a Historic Assessment Study, changing submittal scope.	Verify whether Samoa/Scotia DRCs are active; if not, expect Historic Assessment Study requirements. §§ 19.1.4.1.2.1; 19.1.9.3.2.1
Scope of “development” triggering a Special Permit	The code requires a Special Permit for development in D Zones, but whether modest repairs or small additions trigger the permit may be ambiguous.	Ask Planning staff whether your specific work is exempt (e.g., solar collectors are explicitly exempt). § 19.1.2
Relationship to underlying zone standards (setbacks, coverage)	D Zone controls appearance; dimensional standards often remain those of the underlying zone — conflicting guidance can arise.	Confirm which development standards are governed by the principal zone vs. design criteria. See development standards. § 19.1 D (intro)
Historic criteria interpretation	“Contributing” status and application of Secretary of Interior standards can be subjective and affect demolition/alteration outcomes.	Request written guidance from Planning on whether the structure is contributing and what standards will apply. §§ 19.1.9.1.3; 19.1.4.1.2.1

Plain‑English summary

If your property in an unincorporated part of Humboldt County is mapped with the D (Design Control) overlay, expect to submit a design‑review (special permit) application that shows site layout, elevations, materials, landscaping and parking; reviewers will evaluate height, setbacks, materials, roof, signs, landscaping, and how the project fits historic or scenic contexts — special sub‑area rules apply in Samoa, Scotia, and Shelter Cove. Verify mapping and any active local Design Review Committee before you design final plans. §§ 19.1.1–.5; 19.1.9.; 19.1.4.

Source References

Humboldt County Zoning Code: D Zone / Design Control — §§ 19.1.1–19.1.5 (purpose, applicability, procedure) § 19.1.1–.5
Humboldt County Zoning Code: Architectural Standards for D Zone — §§ 19.1.3.1–19.1.3.9 (review criteria: height, setbacks, materials, roofs, signs, landscaping). § 19.1.3.1–.9
Humboldt County Zoning Code: Samoa design review and standards (alteration/demolition) — §§ 19.1.4.1, 19.1.9.1–1.3 (Samoa DRC authority, demolition findings, Secretary of Interior standards). § 19.1.4.1; § 19.1.9.1–1.3
Humboldt County Zoning Code: Scotia design review / Historic Assessment Study — §§ 19.1.9.3.1–3.3 (Scotia DRC authority; historic assessment content). § 19.1.9.3.*
Humboldt County Zoning Code: Shelter Cove additional design standards — §§ 19.1.4.1.1.1–.1.4 (20 ft min width, Zone IV foundations, 12" overhang, material restrictions). § 19.1.4.1.1.*
Humboldt County Zoning Code: Wireless telecommunications facilities — design review submittals and notice — § 91.2.8.3 and subparts (design checklist, 300‑ft notice, visual impact analysis). § 91.2.8.3.*

Sources

Retrieved passages

CBC § 1913 (section is) High relevance
CBC § 314 (Section INL) High relevance
CBC § 1913 (Section CZ) High relevance
CBC § 2466 (section is) Medium relevance
Humboldt County Zoning Code Medium relevance
CBC § 1913 (Section CZ) Medium relevance
California Building Code Medium relevance
Humboldt County Zoning Code (chapter according) Medium relevance

Cited sections

Humboldt County Zoning Code: **D Zone / Design Control** — §§ **19.1.1–19.1.5** (purpose, applicability, procedure) § 19.1.1–.5 (§ 19.1.1)
Humboldt County Zoning Code: **Architectural Standards for D Zone** — §§ **19.1.3.1–19.1.3.9** (review criteria: height, setbacks, materials, roofs, signs, landscaping). § 19.1.3.1–.9 (§ 19.1.3.1)
Humboldt County Zoning Code: **Samoa design review and standards (alteration/demolition)** — §§ **19.1.4.1**, **19.1.9.1–1.3** (Samoa DRC authority, demolition findings, Secretary of Interior standards). § 19.1.4.1; § 19.1.9.1–1.3 (§ 19.1.4.1)
Humboldt County Zoning Code: **Scotia design review / Historic Assessment Study** — §§ **19.1.9.3.1–3.3** (Scotia DRC authority; historic assessment content). § 19.1.9.3.* (§ 19.1.9.3.)
Humboldt County Zoning Code: **Shelter Cove additional design standards** — §§ **19.1.4.1.1.1–.1.4** (20 ft min width, Zone IV foundations, 12" overhang, material restrictions). § 19.1.4.1.1.* (§ 19.1.4.1.1.)
Humboldt County Zoning Code: **Wireless telecommunications facilities — design review submittals and notice** — § **91.2.8.3** and subparts (design checklist, 300‑ft notice, visual impact analysis). § 91.2.8.3.* (§ 91.2.8.3.)
HumboldtCounty_ZoningCode.md

Frequently asked questions

Do I need design review in unincorporated Humboldt County?

If your parcel is mapped with the D (Design Control) combining zone, then yes: development on those parcels is subject to the D Zone design‑review process and a special permit is required; solar collectors for on‑site use are explicitly exempt. § 19.1.2; § 19.1.3.1–.2

What does the reviewer look at during design review?

The reviewing authority evaluates height, bulk and area; all setbacks; exterior colors, textures and materials; roof type, pitch and material; signage; landscaping and parking layout; relationship to surrounding buildings; historic compatibility; and site treatment including grading and preservation of trees. § 19.1.3.1–.9

What special rules apply if my property is in Samoa?

Samoa has a local Design Review Committee and additional rules: contributing historic structures may not be altered or demolished without County approval, demolition requires specific findings, and reviews should use the Secretary of the Interior’s Standards and the Samoa Design Guidelines. § 19.1.4.1; § 19.1.9.1–1.3

If there is no Design Review Committee for my area, what happens?

Where a DRC (for Samoa or Scotia) is not appointed, the ordinance gives authority to the Director or requires a Historic Assessment Study prepared by a qualified historic consultant; the Director may act as the reviewing authority. §§ 19.1.4.1.2.1; 19.1.9.3.2.1–.2.2

Are there specific construction rules for Shelter Cove?

Yes. Shelter Cove’s design rules include a minimum residence width of 20 feet, foundations meeting seismic Zone IV continuous perimeter foundation standards (with limited exceptions), a minimum 12‑inch roof overhang, and bans on unfinished metal exterior materials unless they carry a 15‑year warranty. § 19.1.4.1.1.1–.1.4

Will design review decide whether I can demolish a historic building?

For contributing historic structures (especially in Samoa and Scotia), demolition is subject to special findings and may be delayed, conditioned, or denied; the County must consider alternatives and apply historic‑preservation standards. Expect documentation requirements and possibly mitigation measures. §§ 19.1.9.1.1–1.3; 19.1.9.3.3.1–.3.3

What extra submittals are required for wireless (telecom) facilities design review?

Tier 2/3 wireless facility design review submittals include a telecommunications design‑review checklist, evidence of pre‑application notice to owners/residents within 300 feet, an alternatives analysis, and a visual impact analysis with photo simulations or a balloon test. § 91.2.8.3.*

Who sets the design review decision criteria and who decides?

Decision criteria are set by the ordinance’s D Zone design standards (the items listed in § 19.1.3) and, for historic areas, Secretary of the Interior standards and area guidelines; decisions are made by the DRC where one exists or by the Planning Director/Board representative in its absence. §§ 19.1.3; 19.1.4.1.2.1

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