Alturas — Overlay Districts

Last reviewed: July 3, 2026

Overview

Alturas’ zoning chapter (Chapter 28) establishes four specific overlay zones that modify or add to the base zoning rules where applied. These overlays are listed in § 28.12.020 and are applied to properties by map amendment; when present an overlay’s rules apply in addition to the parcel’s Primary Zone and the more restrictive rule controls (§ 28.23.020, § 28.23.030). Read this page alongside the city's Alturas Zoning and the Alturas Development Standards pages for related requirements like site layout and setbacks.

The city recognizes four overlays: Airport Safety (-AS), Flood Control (-FC), Downtown Historic District (-DH), and Mobile/Manufactured Home Park (-MHP) (list and notation rules in § 28.12.020).

How overlays work (legal framework)

• Overlays are listed and described in § 28.12.020 and Article II, Division 4 of Chapter 28; they are added to the Zone Maps and shown after the Primary Zone with a dash (example: R1-FC-AS) (§ 28.12.020 B).
• When an Overlay is applied it supplements the Primary Zone: any use allowed in the Primary Zone can still be allowed in an Overlay but must meet overlay-specific restrictions as well as Primary Zone standards; the more restrictive rule applies when there is conflict (§ 28.23.020, § 28.23.030).
• Zone map boundaries, adoption and amendments are governed by § 28.12.030 and changes follow the zone-change process in Article VI, Division 4 (§ 28.12.030). The City’s official Zone Maps are adopted by council and incorporated by reference.

Overlay district–by–district breakdown

Below are the four overlays established by the Alturas Zoning Ordinance, with the ordinance’s stated purpose, typical effects on uses, and the key standards an applicant or reviewer will look for.

Airport Safety Overlay (-AS)

• Purpose: Intended to address airport-related issues (noise/airport safety contour) but currently reserved for future use. No substantive development standards are presently codified for the -AS overlay in the retrieved materials. (§ 28.23.040).
• Typical permitted uses: Uses remain those allowed by the Primary Zone; any airport-specific standards would be additive if adopted later (§ 28.23.030).
• Where it applies: Where the City maps the -AS overlay on the Zone Maps (map locations are not included in the text excerpts here; see § 28.12.030).

Flood Control Overlay (-FC)

• Purpose: Intended to protect public health and safety from flood hazards. In the current ordinance text returned to us the -FC overlay is reserved for future use and contains no operative technical standards in the retrieved materials (§ 28.23.060).
• Typical permitted uses: Primary Zone uses may remain allowed but will be subject to any future -FC standards in addition to Primary Zone standards (§ 28.23.030).
• Where it applies: Applied by map amendment to flood-prone parcels as shown on the City Zone Maps (§ 28.12.030).

Downtown Historic District Overlay (-DH) — the most detailed overlay

• Purpose: Preserve and reinforce Alturas’ pedestrian-oriented historic Main Street retail environment: tight storefronts, continuous building wall, and walkability around Main Street (area described as “within a block or two of Main Street just south of 4th Street and north of the Pit River”) (§ 28.23.050 A).
• Impact on permitted uses: The -DH is not intended to remove Primary Zone uses but requires site planning, and often discretionary review, to protect pedestrian retail character; the C1 (Retail/Office Commercial) Primary Zone is preferred within -DH (§ 28.23.050 B).
• Key dimensional/site standards and design rules (decision‑relevant):
  • Minimum lot size and lot width: No minimum in the -DH (exception to Article IV standards) (§ 28.23.050 C.1).
  • Setbacks: Buildings along Main Street shall have a zero front setback from the front property line unless a Variance is approved (§ 28.23.050 C.2).
  • Flag lots are prohibited within the -DH (§ 28.23.050 C.3).
  • Landscape, parking and loading standards: Exempt from the typical Article IV standards for the -DH (i.e., the usual parking/landscape references in Article IV do not apply the same way) (§ 28.23.050 C.4). Note: See the City’s Alturas Parking page for parking policy background, but the overlay text specifically exempts some standard requirements.
  • Signage: Building signs are preferred; Monument and LED signs are prohibited; Pole signs and off‑premise signs allowed only by Use Permit in limited circumstances (§ 28.23.050 C.5). See the city’s Alturas Signage guidance for broader sign rules.
  • Design review flexibility: Discretionary approvals, including Site Plan or Use Permits, may be conditioned to change materials, colors, lighting, building design, landscaping and screening to protect pedestrian orientation (§ 28.23.050 C.6). The City’s Alturas Design Review process is the pathway for such conditions.
• Where it applies: Centered on Main Street (block or two south of 4th Street to the Pit River); consult the official Zone Maps for parcel-level application (§ 28.23.050 A; § 28.12.030).

Mobile/Manufactured Home Park Overlay (-MHP)

• Purpose: Identify properties developed as mobile/manufactured home parks and ensure they meet State and local park standards (§ 28.23.070 A–C).
• Required compliance: All MHPs must comply with the California Mobile Home Parks Act (Health & Safety Code § 18200 et seq.) and HCD regulations (Title 25 CA Code of Regulations), and also the local standards of § 28.38.100 (the ordinance’s mobile home park development standards) (§ 28.23.070 B–C). Verify both State and local standards when proposing an MHP.
• Typical permitted uses: Mobile/manufactured home park uses as described in the Land Use Matrix (see Article II and Table references; the specific park operation standards are tied to § 28.38.100).
• Where it applies: Applied by mapping to properties where a mobile/manufactured home park exists or is proposed (§ 28.23.070 A; § 28.12.030).

Quick reference table — decision‑relevant standards

Practical guidance and comparisons

• The -DH overlay is the only overlay in the ordinance with active, design‑forward controls. It relaxes some technical site constraints (no minimum lot size, exemptions for parking/landscape standards) specifically to encourage traditional Main Street patterns, but simultaneously tightens urban design expectations (zero setbacks, signage limits, visual material controls) — expect design review and site plan conditioning under § 28.23.050 C.
• If your parcel carries more than one overlay (e.g., R1-FC-AS), both overlays apply plus the Primary Zone; conflicts are resolved by applying the more restrictive provision (§ 28.23.020, § 28.23.030).
• For -MHP projects, do not rely on the Zoning Ordinance alone — you must comply with State park law (Health & Safety Code and Title 25) AND local Section § 28.38.100; the ordinance explicitly requires both (§ 28.23.070 B–C).
• The ordinance directs you to the official Zone Maps for parcel‑level overlay locations; if a map boundary is unclear, the map‑boundary interpretation rules apply and the Director/Commission may issue determinations (§ 28.12.030; § 28.10.030) — verify the map before designing a project.

Checklist

An applicant proposing development in an Overlay Zone should ensure they have the following (each item links to the ordinance citation to verify):

• Confirm whether the parcel is mapped with an overlay on the City Zone Maps (Zone Maps adopt rules in § 28.12.030)
• Confirm which Overlay(s) apply (list located in § 28.12.020) and note the overlay suffix notation (e.g., R1-FC-AS) (§ 28.12.020 B)
• Read and apply overlay‑specific development rules in Article II, Division 4 (for example § 28.23.050 for -DH) in addition to Primary Zone standards (§ 28.23.020, § 28.23.030)
• Prepare a Site Plan and elevations for any non‑single‑family projects; Site Plan review requirements and the relationship to permits are in § 28.42.010 and § 28.42.030 (Site Plan often required where overlays impose design controls)
• If seeking a variance from overlay standards (e.g., front setback), prepare the Variance findings and materials required by § 28.52.050 (demonstrate special circumstances)
• For -MHP, assemble State compliance documentation (HCD/Title 25) plus the materials required by local § 28.38.100 (§ 28.23.070 B–C)

Risks & Ambiguities

Plain‑English summary

Alturas’ ordinance creates four specific overlays that sit on top of the base zone for a property. The Downtown Historic District (-DH) is the only overlay with active design and setback rules (zero setbacks on Main Street, signage limits, etc.); the Mobile Home Park (-MHP) overlay requires compliance with State park law plus local standards; the Airport Safety (-AS) and Flood Control (-FC) overlays are listed but reserved for future use. Always check the official Zone Maps and apply both the overlay and the Primary Zone standards — the more restrictive rule applies. Verify parcel mapping and full text of cited sections with the City.

Source References

• § 28.12.020 — Established overlay zone districts; overlay notation and list (Airport Safety, Flood Control, Downtown Historic District, Mobile Home Park).
• § 28.12.030 — Zone maps; adoption and amendments.
• § 28.23.020 — Overlay application; overlays add to Primary Zone requirements and the more restrictive provision applies.
• § 28.23.030 — Effect on allowed uses, permits, and development standards.
• § 28.23.040 — Airport safety (-AS) overlay (reserved for future use).
• § 28.23.050 — Downtown Historic District (-DH) overlay (purpose, zero setbacks, signage, exemptions, site plan criteria).
• § 28.23.060 — Flood control (-FC) overlay (reserved for future use).
• § 28.23.070 — Mobile/Manufactured Home Park (-MHP) overlay; requires State and local compliance and references § 28.38.100.
• Site plan and permit relationship: § 28.42.010, § 28.42.030 (Site Plan applicability and relationship to permits).
• Variances and permit findings: § 28.52.050 (Variance requirements and application materials) and Use Permit findings in Article V (various).

Retrieved passages

• Alturas Zoning Code (Section 65851) High relevance show source text
• Alturas Zoning Code (chapter to) High relevance show source text
• Alturas Zoning Code (Section pursuant) High relevance show source text
• CBC § 28.52.050 (Article IV) High relevance show source text
• Alturas Zoning Code (§ 1) High relevance show source text
• Alturas Zoning Code (Section describes) Medium relevance show source text
• Alturas Zoning Code (Article II) Medium relevance show source text
• Alturas Zoning Code (chapter and) Medium relevance show source text

Cited sections

• **§ 28.12.020** — Established overlay zone districts; overlay notation and list (Airport Safety, Flood Control, Downtown Historic District, Mobile Home Park). (§ 28.12.020)
• **§ 28.12.030** — Zone maps; adoption and amendments. (§ 28.12.030)
• **§ 28.23.020** — Overlay application; overlays add to Primary Zone requirements and the more restrictive provision applies. (§ 28.23.020)
• **§ 28.23.030** — Effect on allowed uses, permits, and development standards. (§ 28.23.030)
• **§ 28.23.040** — Airport safety (-AS) overlay (reserved for future use). (§ 28.23.040)
• **§ 28.23.050** — Downtown Historic District (-DH) overlay (purpose, zero setbacks, signage, exemptions, site plan criteria). (§ 28.23.050)
• **§ 28.23.060** — Flood control (-FC) overlay (reserved for future use). (§ 28.23.060)
• **§ 28.23.070** — Mobile/Manufactured Home Park (-MHP) overlay; requires State and local compliance and references **§ 28.38.100**. (§ 28.23.070)
• Site plan and permit relationship: **§ 28.42.010**, **§ 28.42.030** (Site Plan applicability and relationship to permits). (§ 28.42.010)
• Variances and permit findings: **§ 28.52.050** (Variance requirements and application materials) and Use Permit findings in Article V (various). (§ 28.52.050)
• Alturas_ZoningCode.md

• Official Alturas code library