San Benito County — Overlay Districts

Last reviewed: July 6, 2026

Overview

In unincorporated San Benito County, “overlay districts” are codified as combining zones that layer additional rules on top of a parcel’s base zoning. They can either supplement or replace base-district standards where safety, compatibility, or public-interest objectives require more tailored regulation. The County’s combining zones are established in the zoning ordinance’s Chapter 25.04, and they apply only where mapped in the unincorporated areas; when in conflict, the combining zone’s standards govern over base-zone rules.

Key rule: When an overlay (combining zone) and a base zone conflict, the overlay controls in unincorporated San Benito County. See § 25.04.001(B).

The County currently establishes four named combining zones — Emergency Shelter (ES), Airport Safety (AS), Frazier Lake Airpark (FLA), and Hollister Municipal Airport (HMA) — plus a Planned Unit Development (PUD) combining district codified in a separate chapter. Refer to the County zoning map to see where these apply within unincorporated areas.

How the overlay system fits with base zoning

• Base zones regulate primary use, intensity, and baseline development standards. Combining zones add area-specific limits or allowances, and those rules apply “on top of” the base zone.
• Combining zones are shown on the zoning map; check the map first, then confirm with Planning if the parcel is inside an overlay boundary.

District-by-district breakdown

Emergency Shelter (ES) Combining Zone

Purpose and where it applies

• Allows emergency shelters as-of-right in mapped ES areas in unincorporated County; ES areas are designated on the zoning map.

Typical permitted uses

• Emergency shelters as defined by state law are permitted in addition to uses allowed by the underlying zone.

Key operational and development standards

• Nondiscretionary processing under CEQA for shelters; the County’s review is not a discretionary CEQA action.
• Parking: one vehicle space per employee on the peak shift, plus one per ten beds; off-site/shared and on-street along the site frontage may count toward satisfying the requirement if approved — coordinate early with Parking.
• Facility operation: responsible operator; on-site supervisory staff during operating hours; annual Sheriff-approved security plan; maximum length of stay no longer than the state Health & Safety Code allows.

Notes

• All other standards of the underlying zone continue to apply unless the ES section states otherwise.

Airport Safety (AS) Combining Zone

Purpose and where it applies

• Applies to airports and airstrips in the unincorporated area that are state-licensed with ≥20 operations/month and ≥5 based aircraft, and that do not have a County-adopted Airport Land Use Compatibility Plan (ALUCP).

Typical permitted and prohibited uses

• Land use, coverage, and population density limits vary by safety area. For example, the Runway Protection Zone allows no people and no structures; in the Approach Safety Zone, coverage must be <25% and average density ≤10 persons/acre, with only low-density residential and certain commercial/industrial uses that can meet density/coverage limits.
• Prohibited uses include activities that cause glare, bright/confusing lights, smoke or bird concentrations, electrical interference, or objects that penetrate the utility runway visual approach slope.

Key dimensional and approval standards

• Existing nonconforming structures/uses are generally not required to be removed, but may be required to install warning markers/lights. Variances from AS standards may be considered with FAA input, and conditions (e.g., lighting/marking) may apply — see Variances and Exceptions.

Frazier Lake Airpark (FLA) Combining Zone

Purpose and where it applies

• Applies to every parcel within the Frazier Lake Airpark Airport Influence Area (AIA), as defined in the Frazier Lake ALUCP and mapped in County GIS; the AIA boundary description is codified.

Typical permitted uses

• Permitted/conditional uses vary by airport safety zone per Table 25.04‑A (Runway Protection, Inner Safety, Turning Safety, Outer Safety, Side Safety, Traffic Pattern). For example, assembly uses are not permitted in safety zones near runways but may be allowed in the Traffic Pattern Zone; small day care and many public uses shift from “not permitted” near runways to “permitted/administrative” farther out. Always check the zone column in Table 25.04‑A for the proposed use.

Key dimensional and performance standards

• Population density thresholds per zone cap persons/acre; an application that would exceed the section’s density standards cannot be approved.
• Height is controlled by FAA Part 77 surfaces; projects must show maximum building height (MSL plus roof elements) below the applicable Part 77 surface. Coordinate early with Design Review.
• Additional standards prohibit emissions, glare, lighting, and electronic interference that affect aviation; ground vibration perceptible offsite is also prohibited.
• Submittals: discretionary permits must be referred to the Airport Land Use Commission (ALUC) and include an avigation easement; a supplemental information form with maps and density calculations is required unless waived.

Hollister Municipal Airport (HMA) Combining Zone

Purpose and where it applies

• Applies to every parcel within the Hollister Municipal Airport Influence Area defined by the adopted Hollister ALUCP.

Typical permitted uses

• Table 25.04‑B sets permit requirements by safety zone (Runway Protection, Inner/Outer Approach-Departure, Inner Turning, Side Line, Traffic Pattern). For example, residential is not permitted near the runway but can become permitted or administrative in the Traffic Pattern Zone; many public/semi-public and commercial uses shift from CUP or APR near the runway to permitted farther away.

Key dimensional and performance standards

• Standards mirror FLA: aviation-related limits on emissions, interference, glare, lighting, ground vibration, persons/acre, and height against Part 77 surfaces; noise attenuation to 55 dB CNEL interior for specified occupancies.
• Findings for CUPs in HMA require risk-reduction features (e.g., wall/roof strength, window limits, exits) and compliance with population thresholds.

Notes

• ALUC referral/easement requirements specific to HMA were not located in the retrieved materials; confirm with the County. Not found in retrieved materials.

Planned Unit Development (PUD) Combining District

Purpose and where it applies

• The PUD acts as a combining district, primarily with R‑1 and RM base districts, to enable innovative residential or mixed-use layouts while modifying certain base-zone standards. Each mapped PUD is shown on the zoning map.

Typical permitted uses

• In addition to base-zone uses, a PUD may include single-family, two-family, multifamily, recreation, a mix of neighborhood commercial with residential, and live-work.

Key dimensional and design standards

• Minimum PUD size is one acre or two dwelling units unless otherwise approved; detailed standards for lot size, coverage, setbacks, access, streets, parking, and open space are set by Planning Commission resolution for each PUD.
• Design criteria emphasize context-sensitive buildings, connected street networks, complete streets, and site landscaping and screening; base-district setbacks typically still apply unless modified in the PUD.
• Board of Supervisors findings must show the PUD is superior to base-zone development and consistent with the General Plan; conditions can be imposed.

At‑a‑glance overlay rules (unincorporated areas)

Related special area regulations sometimes mistaken for “overlays”

• Mineral Resource Areas: State‑mapped MR areas trigger special use lists and supplemental standards that can replace base-zone use permissions on affected parcels in unincorporated areas. Not shown on the County zoning map; check Division of Mines and Geology mapping.
• Floodplain Development Standards: Projects in FEMA‑mapped floodplains must meet siting/construction protections; these standards supplement the base zone.
• Hillside/Ridgeline: Area‑based design review and prohibitions for steep slopes and ridgeline proximity along major corridors; this is not a combining zone but functions like an overlay trigger for design review.

Checklist

• Verify the parcel’s base zone and any overlays using the County zoning map and Chapter 25.04 (unincorporated areas only).
• For airport overlays (AS/FLA/HMA), identify the exact safety zone, calculate persons/acre, and confirm proposed coverage and Part 77 height compliance; prepare any ALUC referrals, easements, and supplemental forms required.
• For ES sites, confirm shelter eligibility, parking ratios, and operating/security plan requirements.
• For PUDs, confirm PUD mapping, minimum project size, and the Planning Commission’s project-specific standards and submittals.
• Cross-check applicable development standards, land use permissions, design review triggers, and site landscaping and screening.
• If a standard cannot be met, discuss relief pathways under Variances and Exceptions; for existing situations, review Nonconforming Uses.

Risks & Ambiguities

Plain-English Summary

Overlays (combining zones) are “extra rules” that sit on top of your parcel’s base zoning in unincorporated San Benito County. If your land is inside an airport overlay, expect strict limits on height, lighting, and how many people can be on-site; if it’s in the ES overlay, shelters are allowed by right with defined parking and operating rules; and if it’s in a PUD overlay, the project follows custom, approved standards. Always check the map first, then read the overlay section — the overlay wins if it conflicts with base zoning.

Source References

• § 25.04.001 Purpose and application of combining zones; § 25.04.002 Combining zones established (ES, AS, FLA, HMA); zoning-map applicability.
• § 25.04.003 Emergency Shelter (ES) Combining Zone — permitted use; CEQA processing; parking; operations.
• § 25.04.004 Airport Safety (AS) Combining Zone — intent; applicability; density/coverage/land-use table; prohibited uses; nonconforming/variance provisions.
• § 25.04.005 Frazier Lake Airpark (FLA) Combining Zone — applicability; Table 25.04‑A; height and performance standards; ALUC referral; avigation easement; supplemental info.
• § 25.04.006 Hollister Municipal Airport (HMA) Combining Zone — applicability; Table 25.04‑B; standards; CUP findings.
• §§ 25.05.001–25.05.006 Planned Unit Developments (PUD) — combining-district framework; permitted uses; design criteria; findings and procedures.
• § 25.08.025 Mineral Resource Area Development Regulations (special area standards).
• § 25.08.026 Floodplain Development Standards (special area standards).
• § 25.07.017 Hillside/Ridgeline (area-based design review).

Retrieved passages

• San Benito County Zoning Code (§ 3) High relevance show source text
• San Benito County Zoning Code (§ 3) Medium relevance show source text
• San Benito County Zoning Code (§ 25.05.004) Medium relevance show source text
• San Benito County Zoning Code (§ 3) Medium relevance show source text
• CBC § 25.07.011 (§ 25.07.011) Medium relevance show source text
• CBC § 25.08.016 (§ 25.08.016) Medium relevance show source text
• San Benito County Zoning Code (§ 3) Medium relevance show source text
• San Benito County Zoning Code Medium relevance show source text
• San Benito County Zoning Code (§ 25.04.005) High relevance show source text
• San Benito County Zoning Code (section and) High relevance show source text
• San Benito County Zoning Code (§ 3) High relevance show source text
• San Benito County Zoning Code (CHAPTER 25.05) Medium relevance show source text
• San Benito County Zoning Code (Chapter 25.06) Medium relevance show source text
• San Benito County Zoning Code (§ 3) Medium relevance show source text
• San Benito County Zoning Code Medium relevance show source text

Cited sections

• § 25.04.001 Purpose and application of combining zones; § 25.04.002 Combining zones established (ES, AS, FLA, HMA); zoning-map applicability. (§ 25.04.001)
• § 25.04.003 Emergency Shelter (ES) Combining Zone — permitted use; CEQA processing; parking; operations. (§ 25.04.003)
• § 25.04.004 Airport Safety (AS) Combining Zone — intent; applicability; density/coverage/land-use table; prohibited uses; nonconforming/variance provisions. (§ 25.04.004)
• § 25.04.005 Frazier Lake Airpark (FLA) Combining Zone — applicability; Table 25.04‑A; height and performance standards; ALUC referral; avigation easement; supplemental info. (§ 25.04.005)
• § 25.04.006 Hollister Municipal Airport (HMA) Combining Zone — applicability; Table 25.04‑B; standards; CUP findings. (§ 25.04.006)
• §§ 25.05.001–25.05.006 Planned Unit Developments (PUD) — combining-district framework; permitted uses; design criteria; findings and procedures. (§ 25.05.001)
• § 25.08.025 Mineral Resource Area Development Regulations (special area standards). (§ 25.08.025)
• § 25.08.026 Floodplain Development Standards (special area standards). (§ 25.08.026)
• § 25.07.017 Hillside/Ridgeline (area-based design review). (§ 25.07.017)
• SanBenitoCounty_ZoningCode.md

• Official San Benito County code library