Local zoning · Alpine County

Alpine County — Development Standards

Development Standards under the Alpine County local zoning and planning code, with the controlling citations.

Last reviewed: July 6, 2026

Overview

This page distills development standards that apply in the unincorporated areas of Alpine County under the county’s zoning ordinance (Title 18). It focuses on setbacks, height, parcel size, and selected density/intensity controls that directly affect what can be built and where. For zoning basics and how these districts fit into the county’s General Plan, see the Alpine County Zoning and Alpine County Land Use pages.

The single most universal rule: check your base zoning district, then layer on any countywide standards (like height on the East/West Slope) and any combined/overlay zones—your most restrictive applicable rule controls (§ 18.68.010; § 18.56.050).

How Alpine’s code is organized

Title 18 applies to all lands in the unincorporated areas of Alpine County (§ 18.04.040).
Countywide “general requirements and exceptions” (setbacks, height, yard encroachments, etc.) are in Chapter 18.68 (e.g., height § 18.68.050; yard requirements § 18.68.140).
Some communities and highway corridors use combined/overlay zones; the underlying zone still governs unless the overlay is more restrictive (§ 18.56.050; § 18.64.040–.050).

Countywide Development Standards (apply in addition to your base zone)

Building height (East/West Slope): For non-commercial/industrial/institutional buildings, maximum main-building height varies with slope and whether a site is on the county’s East or West Slope. On the East Slope, max is generally 34–36 ft; on the West Slope, 36–40 ft, with higher limits allowed as lot slope increases (§ 18.68.050.A.1). Accessory buildings are capped at 25 ft (§ 18.68.050.A.2). Height overages require a variance and 1:1 setback increases (§ 18.68.050.A.3).
Yard/encroachment rules: Corner lot “clear-view” protection overrides any listed yards; established subdivision building lines control; eaves, chimneys, and small features may project into yards within stated limits; detached one-story accessory buildings without living space may occupy up to 50% of the required rear yard (§ 18.68.140.A–F). Fences in RE and RN are limited to 6 ft in side/rear yards and 4.5 ft in front yards (§ 18.68.140.H).
Parking: Off-street parking standards are in Chapter 18.68 (see § 18.68.100) and also referenced in multiple districts (e.g., NC, INS, C)—plan for compliance early; see Alpine County Parking.
Lot/parcel adjustments for density: Easements dedicated for public facilities may be subtracted when calculating density; open space clustering through PD/LP zoning can reduce lot sizes while meeting overall plan densities (§ 18.68.020; § 18.04.070.D–E).
ADUs (“Secondary dwelling units”): Allowed by permit in AG, AP, TP, RE, RN, and PD areas that allow single-family uses (§ 18.69.020–.040.G). Local ADU standards cannot undercut state minimums (at least 800 sf and 4-ft side/rear setbacks) under current state law; see California ADU law and the state updates summarized here.

District-by-District Standards (unincorporated areas)

AG — Agricultural Zone (§ 18.16)

Purpose/typical uses: Agriculture and compatible rural uses; various resource and limited recreation uses by use permit (§ 18.16.030).
Key dimensional standards: Parcel area 20 acres; depth should not exceed 2× width; front/side/rear setbacks 30 ft each (§ 18.16.040). Height follows countywide rules in Chapter 18.68 (§ 18.16.050).
Where it applies: Agricultural lands designated on the zoning map; verify parcel zoning with the County.

AP — Agricultural Preserve (Williamson Act) (§ 18.18)

Purpose/typical uses: Preserve productive ag land; nonagricultural subdivisions and commercial/industrial uses are not permitted (§ 18.18.010). One single-family dwelling per 100 acres is a permitted use (§ 18.18.020.B).
Key dimensional standards: Not found in retrieved materials for § 18.18.040 (area/yard). All AP uses must also meet applicable Chapter 18.68 standards (§ 18.18.070).
Where it applies: Lands under Williamson Act contracts; verify parcel-specific standards.

LP — Land Preserve (§ 18.20)

Purpose/typical uses: Keeps open space or resource lands largely undeveloped; allows parks, agriculture, and specified conditional resource/recreation uses (§ 18.20.010–.030).
Key dimensional standards: Not found in retrieved materials for minimum parcel/yard. Development here often ties to PD clustering—verify early.
Where it applies: Open space/common areas created via clustering or where development rights are transferred.

TP — Timber Preserve (§ 18.24)

Purpose/typical uses: Timber resource production and compatible uses; existing single-family dwellings at the time of zoning are recognized (§ 18.24.020.E).
Key dimensional standards: A single-family dwelling may be allowed by use permit at a ratio of one dwelling per 160 acres (quarter-section) (§ 18.24.030.D). Area/yard requirements not found in retrieved materials.
Where it applies: Timber resource lands; verify with the jurisdiction.

PD — Planned Development (§ 18.28)

Purpose/typical uses: Clustering to protect sensitive lands; any use or mix deemed acceptable by an approved development plan (§ 18.28.040).
Key dimensional standards: Structures generally follow the “similar zone” standards unless approved deviations improve the total development; areas with a PD General Plan designation are limited to 2.5 units/households per acre (§ 18.28.050).
Where it applies: Case-by-case mapped PD sites supporting clustered layouts.

RE — Residential Estate (§ 18.32)

Purpose/typical uses: Low-density single-family and mini-ranch activities (§ 18.32.010–.020).
Key dimensional standards: Minimum parcel size is set case-by-case (often denoted as RE-10 for 10-acre minimum, etc.); depth should not exceed 2× width; front/side/rear setbacks 30 ft each (§ 18.32.040).
Where it applies: Large-lot rural residential areas.

RN — Residential Neighborhood (§ 18.36)

Purpose/typical uses: Urban/suburban residential at up to 4 units/acre unless RH GP designation and use permit allow higher (§ 18.36.010). Duplexes/multifamily to 15 units/acre require a use permit and proper GP designation (§ 18.36.030.D).
Key dimensional standards: Minimum parcel size is set site-by-site and may be denoted as RN-30 (30,000 sf), etc.; lot width 80 ft, depth 100 ft; front 30 ft, interior side 20 ft, street-side 30 ft, rear 20 ft (§ 18.36.040).

NC — Neighborhood Commercial (§ 18.40)

Purpose/typical uses: Small-scale neighborhood-serving retail, B&Bs (§ 18.40.020).
Key dimensional standards: Lot area 10,000 sf; front 30 ft; side none (but at least 2× the abutting R-zone side yard if abutting residential; otherwise 30 ft minimum); rear 30 ft; building size limit 2,500 sf main building; height follows countywide dwelling limits (§ 18.40.040–.060).

C — Commercial (§ 18.44)

Purpose/typical uses: Business centers of the county (§ 18.44.010).
Key dimensional standards: Lot area 5,000 sf; lot width 50 ft; front 6 ft; side none (if abutting an R zone, not less than the R-zone’s requirement); rear none (if abutting an R zone, at least 20 ft); height ≤45 ft/3 stories (§ 18.44.050–.060).

IND — Industrial (§ 18.48)

Purpose/typical uses: Manufacturing, warehousing, broad commercial uses; notable heavy uses require a use permit (§ 18.48.020–.030).
Key dimensional standards: Lot area 1 acre; front 20 ft; side/rear none except 50 ft when abutting another zone; height ≤45 ft (§ 18.48.040–.050).

INS — Institutional (§ 18.52)

Purpose/typical uses: Public agency/utility facilities (§ 18.52.010–.020).
Key dimensional standards: Front 30 ft, side 20 ft, rear 20 ft; height ≤50 ft (when abutting an R zone, apply countywide height rules in § 18.68.050) (§ 18.52.040–.050).

Combined / Overlay Districts

CR — Commercial Recreation Combined: Adds highway-visitor retail/recreation allowances; dimensional standards defer to the underlying zone unless a use permit authorizes changes (§ 18.64.020, § 18.64.040–.050). See Alpine County Overlay Districts.
MHD — Markleeville Historic District Combined: Within the Markleeville townsite, permitted uses follow the underlying zone; dimensional standards match the underlying zone unless the adopted Markleeville design guidelines are more restrictive (§ 18.56.040–.050). Projects often need design review—coordinate early; see Alpine County Design Review and Alpine County Historic Preservation.

Quick Reference Table — Selected Dimensional Standards (unincorporated areas)

District	Min Lot Area / Width	Setbacks (Front/Side/Rear)	Height	Notable Density/Intensity	Code Reference
AG	20 acres; depth ≤ 2× width	30 ft / 30 ft / 30 ft	Per § 18.68.050	Not specified	§ 18.16.040–.050
AP	Not found in retrieved materials	Not found in retrieved materials	Per § 18.68.050	1 SF dwelling/100 acres (permitted)	§ 18.18.020, § 18.18.070
LP	Not found in retrieved materials	Not found in retrieved materials	Per § 18.68.050	Resource/open space; PD clustering typical	§ 18.20.010–.030
TP	Not found in retrieved materials	Not found in retrieved materials	Per § 18.68.050	1 SF dwelling/160 acres (CUP)	§ 18.24.030.D
RE	Site-specific; often RE-# in acres	30 ft / 30 ft / 30 ft	Per § 18.68.050	Low-density SFD	§ 18.32.040
RN	Site-specific; may be RN-# in 1,000s sf	30 ft / 20 ft interior, 30 ft street-side / 20 ft	Per § 18.68.050	4 du/ac; up to 15 du/ac with CUP & RH GP	§ 18.36.040, § 18.36.010–.030.D
NC	10,000 sf lot	30 ft / none (see notes) / 30 ft	Per § 18.68.050	2,500 sf max main building	§ 18.40.040–.060
C	5,000 sf, 50-ft width	6 ft / none (R-adjacent = R standard) / none (R-adjacent = 20 ft)	≤ 45 ft / 3 stories	—	§ 18.44.050–.060
IND	1 acre	20 ft / none (50 ft if abutting another zone) / none (50 ft if abutting another zone)	≤ 45 ft	—	§ 18.48.040–.050
INS	Per GP; 30/20/20 yards	30 ft / 20 ft / 20 ft	≤ 50 ft; apply § 18.68.050 near R	—	§ 18.52.040–.050

Notes:

“Per § 18.68.050” means countywide height rules (East/West Slope and slope-based thresholds) apply.
In NC, when abutting a residential zone, side yard must be at least twice the abutting R-zone side yard; otherwise a minimum 30 ft side yard applies (§ 18.40.040.C).

Practical standards that trip up projects

East vs. West Slope height breaks are unique to Alpine County—confirm which slope your site is on and how slope within the building envelope is measured before designing (§ 18.68.050.A.1).
Corner-lot visibility can override listed front/side yards—sight distance wins (§ 18.68.140.A).
In mapped historic areas, the more restrictive Markleeville design guidelines can control details even when base-zone setbacks are met (§ 18.56.050). Coordinate early with Alpine County Design Review.
Nonconformities are regulated in Chapter 18.72—expansions or rebuilds follow detailed rules; see Alpine County Nonconforming Uses.

Checklist

Confirm your parcel’s base zoning and any combined/overlay zones on the county map; start with Alpine County Zoning.
Verify minimum parcel size and any numeric suffix (e.g., RE-10, RN-30) in your district (§ 18.32.040; § 18.36.040).
Apply countywide height rules (East/West Slope, slope-based thresholds) and any district-specific height caps (§ 18.68.050; § 18.44.050; § 18.48.050; § 18.52.050).
Lay out setbacks to meet both district yards and yard encroachment limits (§ 18.68.140 and your district’s yard section).
If in RN, check whether your intended density stays ≤ 4 du/ac or needs a use permit and RH designation for higher density (§ 18.36.010–.030.D).
If proposing an ADU, confirm § 18.69 allowance and state minima; see California ADU law and Chapter 18.69 (§ 18.69.020–.040).
If in the Markleeville townsite, coordinate early with design review; base-zone setbacks still apply unless the historic guidelines are stricter (§ 18.56.050).
Confirm off-street parking requirements and any site access/visibility constraints (§ 18.68.100; § 18.68.140). See Alpine County Parking.

Risks & Ambiguities

Issue	Why it matters	What to verify
East vs. West Slope height thresholds	Triggers different height maxima for the same building	Ask Planning which slope your parcel is on and how slope within the building envelope is measured (§ 18.68.050.A.1).
AP/TP yard and lot standards	Not present in retrieved materials	Request current § 18.18.040 and TP area/yard criteria; apply Chapter 18.68 by default (§ 18.18.070).
RN/RE “site-by-site” parcel sizing	Minimums depend on services and site constraints	Confirm the specific numeric suffix (RN-##, RE-##) and any GP timing constraints (§ 18.32.040; § 18.36.040; § 18.04.060).
Yard encroachments	Can alter usable building envelope	Apply § 18.68.140 for eaves, porches, accessory buildings, and corner-lot visibility.
Historic overlay (MHD)	Design review and stricter guidelines may apply	Confirm if the parcel is inside the Markleeville townsite and whether guidelines impose tighter standards (§ 18.56.050).
ADU preemption	State minima can override local limits	Ensure your ADU is processed ministerially and meets state minima on size/setbacks as updated in 2025 guidance.
Industrial/commercial adjacency	Extra yards when abutting R zones	Apply NC/C/IND adjacency rules (e.g., NC side yard ≥ 2× R-yard; IND 50 ft when abutting another zone) (§ 18.40.040; § 18.44.060; § 18.48.040).

Plain-English Summary

If you’re building in unincorporated Alpine County, start with your zoning district and add the countywide rules on height and yards. Residential estates and neighborhoods have big setbacks (often 20–30 feet), commercial areas are tighter (as little as 6 feet in the C zone), and industrial sites can be tall and close to lines unless they abut other zones. Watch the special East/West Slope height caps, and if you’re in Markleeville’s historic area, expect extra design rules.

Source References

Applicability and General Plan links: § 18.04.040–.070.
Countywide standards: § 18.68.020 (density calcs/open space); § 18.68.050 (height, East/West Slope); § 18.68.140 (yard rules/encroachments).
Agricultural/Resource: § 18.16 (AG); § 18.18 (AP); § 18.20 (LP); § 18.24.030 (TP).
Residential: § 18.32 (RE); § 18.36 (RN).
Commercial/Industrial/Institutional: § 18.40 (NC); § 18.44 (C); § 18.48 (IND); § 18.52 (INS).
Combined/Overlays: § 18.64 (CR); § 18.56 (MHD).
PD/Clustering: § 18.28.040–.050 (PD).
ADUs/Secondary units: § 18.69.020–.040; State 2025 updates (Gov. Code summarized).
For related topics: Alpine County Design Review, Alpine County Overlay Districts, Alpine County Parking, Alpine County Nonconforming Uses, Alpine County Variances and Exceptions, California Building Standards Code, California ADU law.

Information Gaps

AP (Agricultural Preserve) § 18.18.040 minimum parcel size and yard standards: Not found in retrieved materials.
Timber Preserve (TP) area/yard minimums: Not found in retrieved materials.
Countywide lot coverage and floor-area-ratio (FAR) standards: Not found in retrieved materials.

Sources

Retrieved passages

CBC § 5.00 (title shall) High relevance
Alpine County Zoning Code (§ 9.03) High relevance
CBC § 5.02 (§ 5.02) High relevance
Alpine County Zoning Code (§ 13.05) High relevance
Alpine County Zoning Code High relevance
CBC § 1 (Section 18.16.020) High relevance
CBC § 66314 (§ 66314) Medium relevance
Alpine County Zoning Code (Section 18.08.640) Medium relevance
Alpine County Zoning Code (Chapter 18.68) High relevance
Alpine County Zoning Code (§ 1) Medium relevance
Alpine County Zoning Code (§ 10.02) Medium relevance
Alpine County Zoning Code (title shall) Medium relevance
Alpine County Zoning Code (Section 18.56.020) Medium relevance
Alpine County Zoning Code (Chapter 18.68) Medium relevance
CBC § 1 (Section 18.16.020) Medium relevance
Alpine County Zoning Code (§ 1) Medium relevance
Alpine County Zoning Code (Chapter 18.68) High relevance
Alpine County Zoning Code (§ 5) Medium relevance
Alpine County Zoning Code (§ 1) Medium relevance

Cited sections

Applicability and General Plan links: **§ 18.04.040–.070**. (§ 18.04.040)
Countywide standards: **§ 18.68.020 (density calcs/open space)**; **§ 18.68.050 (height, East/West Slope)**; **§ 18.68.140 (yard rules/encroachments)**. (§ 18.68.020)
Agricultural/Resource: **§ 18.16 (AG)**; **§ 18.18 (AP)**; **§ 18.20 (LP)**; **§ 18.24.030 (TP)**. (§ 18.16)
Residential: **§ 18.32 (RE)**; **§ 18.36 (RN)**. (§ 18.32)
Commercial/Industrial/Institutional: **§ 18.40 (NC)**; **§ 18.44 (C)**; **§ 18.48 (IND)**; **§ 18.52 (INS)**. (§ 18.40)
Combined/Overlays: **§ 18.64 (CR)**; **§ 18.56 (MHD)**. (§ 18.64)
PD/Clustering: **§ 18.28.040–.050 (PD)**. (§ 18.28.040)
ADUs/Secondary units: **§ 18.69.020–.040**; State 2025 updates (Gov. Code summarized). (§ 18.69.020)
For related topics: Alpine County Design Review, Alpine County Overlay Districts, Alpine County Parking, Alpine County Nonconforming Uses, Alpine County Variances and Exceptions, California Building Standards Code, California ADU law.
AlpineCounty_ZoningCode.md
2025 California ADU handbook.md

Frequently asked questions

What can I build on an RE lot in Alpine County?

RE is for low-density single-family homes and mini-ranch activities. Minimum parcel size is set case-by-case (e.g., RE-10 means a 10-acre minimum), and standard setbacks are 30 feet on all sides (§ 18.32.040). Height follows the county’s East/West Slope rules (§ 18.68.050). Verify your specific RE suffix and slope early.

What are the RN residential setbacks and density?

Standard RN setbacks are 30 ft front, 20 ft interior side (30 ft street-side on a corner), and 20 ft rear (§ 18.36.040). Base density is up to 4 units/acre; duplexes or multifamily up to 15 units/acre require a use permit and the RH General Plan designation (§ 18.36.010, § 18.36.030.D).

How tall can a house be on the West Slope?

For non-commercial/industrial/institutional buildings, West Slope maximums are 36–40 ft depending on the lot’s slope within the building envelope; accessory buildings top out at 25 ft (§ 18.68.050.A.1–2). Heights above the limit need a variance and added setbacks (§ 18.68.050.A.3).

Do I need design review in the Markleeville historic area?

If your project is within the Markleeville townsite, the MHD combined zone applies. Uses and base setbacks follow the underlying zone, but the historic design guidelines can be more restrictive and trigger design review (§ 18.56.040–.050). Coordinate with Planning before finalizing plans.

What are commercial setbacks in the C zone?

The C zone requires a 6 ft front yard; side and rear yards are generally none, except when abutting a residential zone (then match or exceed the residential standard; rear at least 20 ft) (§ 18.44.060). Maximum height is 45 ft or three stories (§ 18.44.050).

Can I add an ADU in Alpine County?

Yes. “Secondary dwelling units” are allowed by permit in AG, AP, TP, RE, RN, and PD areas that allow single-family uses (§ 18.69.020–.040.G). State law also guarantees an ADU pathway of at least 800 sf with 4-ft side/rear setbacks; local rules must accommodate those minimums. See our ADU law summary.

What if my NC site abuts a residential lot?

In NC, side yards are generally not required, but if your lot abuts a residential zone, you must provide a side yard at least twice the R-zone’s side yard requirement; otherwise a 30-ft minimum applies (§ 18.40.040.C). Height follows the countywide dwelling rules (§ 18.40.060, § 18.68.050).

How do yard encroachments work (eaves, porches, accessory buildings)?

Eaves, canopies, and similar features can project up to 2 ft into required yards; porches and stairs can extend up to 6 ft into front/rear yards and up to half the required width into side yards. One-story detached accessory buildings without living quarters may occupy up to 50% of a required rear yard (§ 18.68.140.D–F).

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