Glenn County — Nonconforming Uses

Last reviewed: July 3, 2026

Overview

This page explains how Glenn County treats nonconforming uses, nonconforming structures, and nonconforming lots in the unincorporated areas under the Glenn County zoning code (Title 15). The county’s core rules are in § 15.06.010 and § 15.06.020 and apply across zones; district-specific standards (setbacks, heights, lot sizes) in each zone still control dimensional and rebuilding requirements. Expect the county to require permits for expansions, permit reconstruction to prior size only under limits, and to consider a use abandoned after six months of inactivity. For related topics see the county pages on parking, development standards & setbacks, design review, overlay districts, and state-level ADU rules (see California ADU law) and the California Building Standards Code.

Notes up front:

• The nonconforming-use rules are countywide for unincorporated Glenn County and reference in-code definitions for “nonconforming use,” “nonconforming building,” and “nonconforming lot” (see § 15.04 definitions).
• The core nonconforming rules are at § 15.06.010 (uses/structures) and § 15.06.020 (nonconforming lots / lot line adjustments).

Key Standards (what the code says, plain-English)

• Continued lawful uses: A use lawfully established before a zoning change may continue even if it no longer conforms to the current zone, subject to controls on expansion and reconstruction. § 15.06.010(1–2).
• Enlargement thresholds: For nonresidential uses, an expansion of 21% or more requires a conditional use permit; expansions of 20% or less require an administrative permit. Residential uses are excepted from the 21% threshold for conditional use (see § 15.06.010(2)).
• Reconstruction after damage: A nonconforming building damaged/destroyed may be restored only if it is made to conform to current regulations other than the use restriction, and the rebuilt floor area may not exceed the prior total floor area (§ 15.06.010(3)).
• Abandonment: If the actual operation of a nonconforming use ceases for a continuous period of six months, the use is deemed abandoned unless the owner proves otherwise; then the property must comply with the current code (§ 15.06.010(4)).
• Nonconforming lots and adjustments: A lot that was legal before the code but is smaller than current minimums may still be used for permitted zone uses but must meet other standards. Lot line adjustments are allowed provided the number of nonconforming lots does not increase; a nonconforming lot may be reduced in area by no more than 20% if the adjustment results in conformance with setbacks and legal creation can be documented (§ 15.06.020(1–2)).

District-by-district breakdown (where and how these rules interact with zone standards)

The nonconforming rules in § 15.06 apply to all unincorporated Glenn County zones; each zone’s own dimensional and permitted-use rules still govern how a nonconforming building/lot may be treated on rebuild, enlargement, or lot-line work. Below are representative Glenn County zones with their purpose, typical permitted uses, and key dimensional standards you must check when dealing with a nonconforming feature.

AE (Exclusive Agricultural) — § 15.33

• Purpose: Preserve large-scale agriculture; allow farm buildings and low-density residences. § 15.33.010–.020.
• Typical permitted uses: Single-family dwellings, agricultural production, farm buildings. § 15.33.020.
• Key dimensional standards: Residential max height 35 ft, agricultural structures up to 50 ft; front yard 30 ft, side/rear 25 ft. § 15.33.060–.080.
• Where it applies: Rural agricultural areas identified in the General Plan and county maps. Verify parcel designation with the county. (Verify with the jurisdiction.)

AT (Agricultural Transitional) — § 15.34

• Purpose: Buffer between agricultural land and urban development; allow low-density residential. § 15.34.010.
• Typical uses: One single-family dwelling per parcel, limited agricultural uses. § 15.34.020.
• Key standards: Lot area and yard rules in § 15.34.050–.070; check for site plan review triggers.

RE (Residential Estate) — § 15.35

• Purpose: Larger-lot residential living with agricultural accessory uses. § 15.35.010.
• Typical uses: Single-family dwellings, accessory farm buildings. § 15.35.020.
• Key dimensional standards: RE-1 min parcel 40,000 sq ft; front yard 30 ft, side yards generally 15–25 ft, rear 25 ft; building heights: residential 35 ft, agricultural 50 ft. § 15.35.050–.070.

RZ (Ranching Zone) — § 15.31

• Purpose: Very-low-density residential/ranch uses on large acreage. § 15.31.010.
• Typical uses: Single-family dwellings on larger parcels, farm buildings, accessory uses. § 15.31.040–.050.
• Key standards: Minimum parcel sizes often large (e.g., 144 acres minimum in RZ described in code excerpts); height limits similar to agricultural zones; yard minimums front 30 ft, side/rear 25 ft. § 15.31.050–.080.

FA (Foothill Agricultural/Forestry) — § 15.32

• Purpose: Protect timber/forest lands and extensive agriculture. § 15.32.010.
• Typical uses: Farming, forestry, one dwelling per acreage standard. § 15.32.020.
• Key standards: Site area, height, and setbacks described in § 15.32.050–.090.

CC (Community Commercial) — § 15.40

• Purpose: Provide neighborhood- and community-serving commercial uses in unincorporated areas. § 15.40.010.
• Typical uses: Retail, services, offices; specific permitted uses laid out in § 15.40.020–.040.
• Key standards: Lot sizes, setbacks, coverage and height are set in § 15.40.050–.100; check these when reconstructing or expanding a nonconforming commercial building.

MP (Industrial Park) — § 15.51

• Purpose: Clustered industrial/light manufacturing with design and screening standards. § 15.51.010–.020.
• Typical uses: Light manufacturing, warehousing, administrative uses; outdoor storage limits and screening requirements apply. § 15.51.030–.040.
• Key standards: Yards, lot coverage and maximum heights in § 15.51.050–.110; site plan review required before permits. § 15.51.120.

Important: when applying § 15.06 to any zone, you must cross-check the zone’s dimensional rules (setbacks, height, lot coverage) found in that zone chapter and in the county development standards. Nonconforming status does not waive those dimensional controls for reconstruction or modifications that the code requires to be brought into compliance. (Verify with the jurisdiction.)

Quick Reference Table — Decision-relevant items

Checklist (what an applicant must satisfy when dealing with a nonconforming use/structure/lot)

• Demonstrate the use/building/lot was lawfully established at the time the Glenn County code (Title 15) or relevant amendment became effective (provide deeds, permits, historical records). § 15.06.010; Definitions in § 15.04.
• If proposing an enlargement: calculate percent increase in area. If >21% (nonresidential), submit a Conditional Use Permit application; if ≤20%, submit an Administrative Permit. § 15.06.010(2).
• If the building was damaged/destroyed: prepare rebuild plans that bring the structure into conformance with all current regulations except use restrictions and show total floor area does not exceed prior area. § 15.06.010(3).
• If a nonconforming lot: assemble recorded subdivision map or other proof of legal creation; for lot-line adjustment, show that the number of nonconforming lots will not increase and that post-adjustment setbacks will conform. § 15.06.020(1–2).
• If expanding, reconstructing or changing use, verify zone-specific setbacks, heights, lot coverage and site-plan requirements in the applicable zone chapter (e.g., § 15.33, § 15.35, § 15.51, etc.) and submit required site plans and permits.
• Expect to demonstrate to the county that the nonconforming use has not been abandoned (if applicable) or provide evidence to rebut presumed abandonment. § 15.06.010(4).

Risks & Ambiguities

Plain-English Summary

If your use, building, or lot in unincorporated Glenn County was lawfully established before a zoning change, you can usually keep it—but enlargements, rebuilds after damage, and lot-line changes have specific limits: small expansions (≤20%) use an administrative permit, bigger ones (≥21%) need a conditional use permit; reconstruction cannot exceed the former total floor area and must comply with current dimensional rules; and if a nonconforming use stops for six months it’s presumed abandoned. Check the zone-specific rules for setbacks, heights, and lot sizes and bring documentation proving the lawful origin of the use or lot. § 15.06.010–.020.

Source References

• Glenn County Code, Title 15 — 15.06.010 Nonconforming Uses (continued use, enlargement thresholds, reconstruction, abandonment).
• Glenn County Code, Title 15 — 15.06.020 Nonconforming Uses and Property (nonconforming lots, lot-line adjustments, 20% reduction rule).
• Glenn County Code — Definitions including “nonconforming building / lot / use” (Title 15 definitions). § 15.04 (definitions).
• AE zone (Exclusive Agricultural) standards (heights, yards). § 15.33.
• AT zone (Agricultural Transitional). § 15.34.
• RE zone (Residential Estate) requirements (lot sizes, yards, heights). § 15.35.
• RZ zone (Ranching Zone) and FA (Foothill Agricultural/Forestry) summaries. § 15.31, § 15.32.
• MP (Industrial Park) district uses and standards. § 15.51.
• CC (Community Commercial) district standards. § 15.40.
• State ADU guidance (2025 ADU handbook) on nonconforming zoning and ADUs (for interaction with county practice).

Information Gaps

• County-specific written interpretation of how the county measures the “percent enlargement” baseline (e.g., conditioned floor area vs. gross area) is not found in the retrieved materials — Verify with the Planning & Community Development Services Agency. Not found in retrieved materials.
• County policy on how building-code upgrades (seismic, accessibility) are enforced upon reconstruction of a nonconforming building is not detailed in § 15.06 — Verify with Building Division and see California Building Standards Code. Not found in retrieved materials.
• Any local ADU-specific nonconforming provisions in Glenn County code were not found in the Glenn County excerpts provided — consult county Planning staff and California ADU law for state limits. Not found in retrieved materials.

Retrieved passages

• Glenn County Zoning Code (Section 15.09.050) High relevance show source text
• Glenn County Zoning Code (§ 2) High relevance show source text
• CFC § 9 (§ 9) High relevance show source text
• Glenn County Zoning Code (§ 3) High relevance show source text
• CFC § 13 (Section 15.77.) Medium relevance show source text
• Glenn County Zoning Code (§ 2) Medium relevance show source text
• CFC § 5 (§ 5) Medium relevance show source text
• CBC § 2 (Title 15) Medium relevance show source text

Cited sections

• Glenn County Code, Title 15 — **15.06.010 Nonconforming Uses** (continued use, enlargement thresholds, reconstruction, abandonment). (Title 15)
• Glenn County Code, Title 15 — **15.06.020 Nonconforming Uses and Property** (nonconforming lots, lot-line adjustments, 20% reduction rule). (Title 15)
• Glenn County Code — Definitions including “nonconforming building / lot / use” (Title 15 definitions). **§ 15.04** (definitions). (Title 15)
• AE zone (Exclusive Agricultural) standards (heights, yards). **§ 15.33**. (§ 15.33)
• AT zone (Agricultural Transitional). **§ 15.34**. (§ 15.34)
• RE zone (Residential Estate) requirements (lot sizes, yards, heights). **§ 15.35**. (§ 15.35)
• RZ zone (Ranching Zone) and FA (Foothill Agricultural/Forestry) summaries. **§ 15.31**, **§ 15.32**. (§ 15.31)
• MP (Industrial Park) district uses and standards. **§ 15.51**. (§ 15.51)
• CC (Community Commercial) district standards. **§ 15.40**. (§ 15.40)
• State ADU guidance (2025 ADU handbook) on nonconforming zoning and ADUs (for interaction with county practice).
• GlennCounty_ZoningCode.md
• 2025 California ADU handbook.md