Local zoning · Calaveras County

Calaveras County — Overlay Districts

Overlay Districts under the Calaveras County local zoning and planning code, with the controlling citations.

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Last reviewed: July 6, 2026

Overview

In unincorporated Calaveras County, the zoning code adds “overlay” districts on top of a base zone to handle special conditions like airport safety, environmental protection, or site-specific plans. These overlays are listed in Table 17.03.010 and are shown on the County’s Official Zoning Map; one or more overlays can apply to a single parcel. Uses allowed by the base district still apply unless an overlay sets different rules or procedures. See the County’s zoning & planning overview and Zoning pages for context.

Overlays modify or add to the base zone. The Official Zoning Map controls where each overlay applies, and overlay suffixes (e.g., “-AO”, “-EP”, “-PD”) are appended to the base zone on that map.

Below is a district-by-district guide to all overlay districts in Title 17 (unincorporated areas only).

Airport Overflight (AO) Overlay Zone

  • Purpose and where it applies: Protect airport operations and public safety within the Calaveras County Airport Influence Area. Shown as “-AO” on the map.
  • Typical permitted uses: Same as the base zone, but only if consistent with the Calaveras County Airport Land Use Compatibility Plan (ALUCP).
  • Key dimensional/operational standards:
    • Prohibits uses or features that create air navigation hazards (e.g., glare, impaired visibility, thermal plumes, wildlife attractants).
    • Noise: New development exposed to CNEL > 55 dB must meet interior CNEL 45 dB for single-unit dwellings; other residential types require an acoustical study by a Board Certified Acoustical Engineer (21 CCR § 5012).
    • Height: Subject to FAA Part 77 surfaces; nothing in this chapter bars structures/trees up to 35 ft above grade (but higher objects may trigger FAA review and ALUCP limits). FAA notification required at 200 ft AGL or where 100:1 surface is penetrated. Avigation easements/overflight notifications may be required per ALUCP.
    • Existing nonconforming uses continue consistent with the ALUCP.

Environmental Protection (EP) Overlay Zone

  • Purpose and where it applies: Applied to specific parcels/areas previously identified by the County, through discretionary or legislative action, as environmentally sensitive or flood-prone. “-EP” is appended to the base zone.
  • Typical permitted uses: Base uses are allowed only if the project is sited/mitigated to protect the identified resource and is consistent with any adopted mitigation/resource protection plan.
  • Key dimensional/operational standards:
    • No use, development, or ground disturbance unless designed to avoid resource degradation and comply with existing mitigation/resource plans; if none exists, a resource protection plan prepared by a qualified professional is required (with mitigation and monitoring), and any new plan requires CEQA (and, if applicable, NEPA) compliance at the applicant’s expense.
    • Decision-makers must make required findings tying the project to the approved plan before approving development in the EP overlay.

Design Review (DR) Overlay Zone

  • Purpose and where it applies: Identifies areas where design review is mandatory under Chapter 17.29. Includes prescribed areas of Mokelumne Hill and other Board-identified communities with adopted standards; mapped as “-DR.”
  • Typical permitted uses: Same as the base zone, but projects must obtain design review approval and comply with adopted design standards.
  • Key process standards:
    • Design Review authority and procedures are in Chapter 17.29; the Planning Director or Planning Commission is the review authority, depending on project type.
    • Design review may address architecture, materials, site layout, parking, landscaping and screening, and signage.

Parcel Size Limitation (X) Overlay Zone

  • Purpose and where it applies: Flags parcels with a specific minimum size that differs from the base zone and prohibits future subdivision. Often used for density transfers, common-area lots, or mitigation/protection parcels in planned developments. Mapped as “-X.”
  • Typical permitted uses: Uses follow the base zone, but the “-X” overlay limits subdivision and may lock in parcel size constraints arising from past approvals.
  • Key dimensional/operational standards:
    • No future subdivision; the overlay documents unique parcel size/density conditions attached to the lot.

Mineral Extraction (ME) Overlay Zone

  • Purpose and where it applies: Implements SMARA for lands with surface mining; the County intends to apply “-ME” to all mining operations requiring a reclamation plan.
  • Typical permitted uses: Surface mining and related reclamation consistent with an approved permit and plan; other uses per the base zone.
  • Key dimensional/operational standards:
    • No surface mining or land reclamation unless a permit, reclamation plan, and financial assurances are approved. Some activities are exempt (e.g., certain on-site earthmoving integral to construction), but exemptions are narrow—confirm applicability.
    • The County updates mineral resource mapping and may condition nearby development to protect designated mineral resources.

Planned Development (PD) Overlay Zone

  • Purpose and where it applies: Enables coordinated, flexible, site-specific development governed by a PD Plan. Not allowed in the GF, TP, A1, or AP zones. Mapped as “-PD.”
  • Typical permitted uses: Only those included in the adopted PD Plan (any Title 17-permitted or conditional use may be included if consistent with the General Plan).
  • Key dimensional/operational standards:
    • Minimum area: 5 acres (Board may approve smaller where clear public benefits are found).
    • Residential unit caps: Total dwelling units may not exceed General Plan maximums for areas designated residential within the PD. If the PD standards are silent, the base zone’s standards apply.
    • Adoption/procedures: The Board of Supervisors adopts the PD Overlay and PD Plan after Planning Commission hearing; processed as a zoning map amendment with the PD Plan reviewed similar to a conditional use permit; tentative maps should be processed concurrently when applicable. Projects and building permits must conform to the approved PD Plan.

Specific Plan (SP) Overlay Zone

  • Purpose and where it applies: Identifies areas governed by an adopted Specific Plan or designated “Future Specific Plan.” Mapped as “-SP.”
  • Typical permitted uses: The adopted Specific Plan governs uses and development; if the plan is silent, Title 17 governs; unlisted uses are prohibited unless the Director finds them substantially similar to permitted uses.
  • Key dimensional/operational standards:
    • Future Specific Plan areas: No subdivision or new/expanded use until a Specific Plan is adopted; plans are expected to define open space/buffers, resource protection, and a range of housing types consistent with the General Plan.
    • Adopted plans on file include the Copper Mill Specific Plan and Saddle Creek (Calaveras Country Club) Specific Plan.

Quick Reference — Overlay Triggers and Standards

Overlay Where it applies What it changes Key trigger/standard Code Reference
AO Airport Influence Area Adds ALUCP-based land use, noise, height, and hazard controls; may require FAA notice and easements CNEL >55 dB interior noise mitigation; FAA Part 77 surfaces; possible avigation easement/overflight notice § 17.09.020, § 17.09.030–.110
EP Environmentally sensitive/flood-prone parcels Requires resource protection plan/mitigation; CEQA/NEPA for new plans; specific findings No disturbance unless plan exists and findings made § 17.10.010–.050
DR Design review areas (e.g., Mokelumne Hill) Mandates design review and conformance to adopted standards DR approval by Director or Commission per Ch. 17.29 § 17.11.010–.030; § 17.29.020
X Parcels with special minimum size/density history Locks parcel-size; bars future subdivision “-X” noted on map; no further subdivision § 17.12.010–.030
ME Surface mining sites Requires mining permit, reclamation plan, financial assurance; SMARA compliance Apply “-ME” to mining operations needing reclamation plan; exemptions limited § 17.13.020–.040
PD Approved planned developments Uses and standards per PD Plan; flexibility with GP consistency Min. 5 ac (unless exception); not allowed in GF, TP, A1, AP; Board adoption § 17.14.010–.060; § 17.36.030
SP Adopted or Future Specific Plan areas Specific Plan governs; Future SP areas require plan before development Copper Mill and Saddle Creek SPs on file § 17.15.010–.040

How to read the map and boundaries

  • Overlay districts are appended as suffixes to the base zone on the Official Zoning Map (e.g., R1-EP, C2-AO). If boundaries are uncertain, Title 17 provides rules for interpreting lines that follow streets, parcel lines, and jurisdictional limits. Always confirm the applicable overlays on the current map before designing a project.

Checklist

  • Confirm your parcel’s base zone and overlays on the Official Zoning Map and in Table 17.03.010.
  • If in the AO overlay: check ALUCP consistency; evaluate CNEL exposure; prepare acoustical design as needed; verify height against FAA Part 77; submit FAA 7460 notification if triggered; be prepared to dedicate an avigation easement or record an overflight notice.
  • If in the EP overlay: compile prior mitigation/resource plans; if none, commission a qualified professional to prepare a resource protection plan; ensure CEQA/NEPA is completed for any new plan; draft required findings.
  • If in the DR overlay: scope design review submittals (site/architecture, landscaping, parking, signage) and identify the review authority.
  • If in the X overlay: confirm no further subdivision is proposed; verify any recorded density transfer/common area conditions.
  • If in the ME overlay: confirm a surface mining permit path, reclamation plan content, and financial assurances; screen for exemptions; align with SMARA processes.
  • If in the PD overlay (or pursuing one): verify eligibility (not GF/TP/A1/AP), minimum area, and General Plan consistency; coordinate PD Plan adoption with any tentative map; ensure all permits/building plans conform to the PD Plan.
  • If in an SP overlay or Future SP area: confirm Specific Plan governing standards and permitted uses; ensure your proposal is listed or is substantially similar; in Future SP areas, pause subdivision/new uses until a plan is adopted.

Risks & Ambiguities

Issue Why it matters What to verify
Overlapping overlays (e.g., AO + EP) Multiple standards can compound (noise, height, mitigation) Map all overlays; coordinate design to satisfy the most restrictive standard; consider variances and exceptions only where allowed.
AO noise/height vs. building design May drive costly materials, layouts, or height reductions CNEL exposure, Part 77 surfaces, and ALUCP mapping; whether 35-ft safe harbor applies or FAA 7460 is needed.
EP resource plan adequacy Inadequate mitigation can stall approvals and CEQA Qualified professional scope, monitoring, and CEQA steps for any new plan; decision-maker findings.
DR standards vary by community Submittal content and design themes differ by adopted standards Which DR standards apply (e.g., Mokelumne Hill) and which body reviews.
X overlay and historic conditions Recorded restrictions can block subdivisions Title history for density transfers/common areas; current “-X” map suffix.
ME exemptions Misreading exemptions can risk unpermitted mining Confirm activity type against § 17.13.040 exemptions and need for permit/reclamation plan/assurances.
PD Plan “silences” If PD Plan omits a standard, default base-zone rules apply Which standards the PD Plan sets vs. which revert to Title 17 base standards.
SP vs. Title 17 conflicts Specific Plans supersede where adopted Whether the parcel is in an adopted SP; if silent, Title 17 governs; unlisted uses are prohibited unless found substantially similar.

Plain-English Summary

In unincorporated Calaveras County, overlays are add-ons to zoning that handle special situations: airport safety (AO), environmental protections (EP), extra design review (DR), locked-in parcel sizes (X), mining rules (ME), customized planned developments (PD), and Specific Plans (SP). Before you design anything, check your map suffixes; overlays can change what you’re allowed to build, add studies/permits, or require special approvals—and your project must meet both base-zone rules and any overlay standards in Title 17 and applicable plans. See Development Standards for general dimensional rules that still apply alongside overlays.

Source References

  • § 17.03.010–.020 (Establishment of base and overlay districts; Official Zoning Map)
  • § 17.09.010–.110 (Airport Overflight Overlay)
  • § 17.10.010–.050 (Environmental Protection Overlay)
  • § 17.11.010–.030 (Design Review Overlay) and § 17.29.010–.040 (Design Review procedures)
  • § 17.12.010–.030 (Parcel Size Limitation Overlay)
  • § 17.13.010–.040 and § 17.13.190 (Mineral Extraction Overlay; Mineral Resource Protection)
  • § 17.14.010–.060 (Planned Development Overlay) and § 17.36.010–.030 (PD procedures)
  • § 17.15.010–.040 (Specific Plan Overlay, adopted plans)

Sources

Retrieved passages

  • Calaveras County Zoning Code (Title 17) High relevance
  • Calaveras County Zoning Code (Title 17) High relevance
  • Calaveras County Zoning Code (Title 17) High relevance
  • Calaveras County Zoning Code (Title 17) High relevance
  • Calaveras County Zoning Code (Section 17.16.140) High relevance
  • Calaveras County Zoning Code (Title 17) High relevance
  • Calaveras County Zoning Code (Chapter 17.13Mineral) Medium relevance
  • Calaveras County Zoning Code (Section 17.02.030.G) Medium relevance

Cited sections

Frequently asked questions

What overlays exist in unincorporated Calaveras County, and how do I find them on my parcel?

The code lists seven overlays: AO, EP, DR, X, ME, PD, and SP. They appear as suffixes on the Official Zoning Map (e.g., R1-DR, C2-AO). Because overlays can stack, always check the current map and Table 17.03.010 before designing.

Does the AO overlay limit how tall my building can be?

Yes. AO height is controlled by FAA Part 77 airspace surfaces and the County’s ALUCP. Some objects up to 35 feet are not prohibited by this chapter, but you may still need FAA 7460 notice at 200 feet AGL or if you penetrate the 100:1 surface; easements/overflight notices may also apply.

I’m in the EP overlay—can I grade for a driveway without extra approvals?

Not until the project is shown to avoid resource harm and is consistent with an approved resource protection/mitigation plan. If no plan exists, you must prepare one (by a qualified professional) and complete CEQA for any new plan before approval; decision-makers must make specific findings.

What does the DR overlay change for a commercial storefront remodel in Mokelumne Hill?

You’ll need design review per Chapter 17.29, and your design must meet the adopted community standards for the mapped DR area. Submittals typically cover architecture, site layout, signage, and landscaping.

My lot is tagged “-X.” Can I still split it?

The X overlay is used to lock minimum parcel size or bar future subdivision—often due to density transfers, common area creation, or mitigation parcels. If your lot has “-X,” assume no further subdivision is allowed unless the overlay is removed through a legislative action.

How does the ME overlay affect a new quarry proposal?

You cannot conduct surface mining unless a permit, reclamation plan, and financial assurances are approved. Limited exemptions exist, but most extraction activities need full SMARA compliance; the County applies “-ME” to operations that require a reclamation plan.

What’s the difference between PD and SP overlays?

A PD overlay is a site-specific planned development with its own PD Plan adopted by the Board; it allows tailored standards but cannot exceed General Plan residential density and isn’t allowed in GF/TP/A1/AP zones. An SP overlay means an adopted Specific Plan governs uses and standards; in Future SP areas, no subdivision or new/expanded use is allowed until a plan is adopted.

If my property is in an overlay, can I get a variance to relax the rules?

It depends. Some overlay standards (especially safety- or resource-based) are hard to vary. Relief may be possible only if you meet the County’s general variance findings and any overlay-specific constraints. Verify with Planning; overlays like AO must remain consistent with the ALUCP.

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