Same zip, different jurisdiction: this page covers LA County Public Works (DPW). The same zip code(s) also cover parts of Avalon (Avalon (its own permits)). Verify your parcel's jurisdiction before filing, different agencies, different rules.
Catalina Island · LA County (Unincorporated)
ADU permits in Two Harbors (Catalina Island)
Zip codes:90704
Two Harbors is a tiny unincorporated community of about 200 year-round residents on Catalina Island's remote 'isthmus', the narrow western half of the island. It is not a city. Building permits run through Los Angeles County Public Works (Building & Safety), though practical permitting is heavily constrained by Catalina Island Conservancy ownership of 88% of the island. The much-larger City of Avalon (incorporated) sits on the island's southern end.
Unincorporated LA County, not LADBS
Two Harbors (Catalina Island) is unincorporated territory. Building permits go through LA County Public Works (Building & Safety) ↗ under LA County Code Title 22, not the Los Angeles Department of Building and Safety (LADBS). Our address checker pulls real feasibility data for any LA County address; the Two Harbors (Catalina Island)-specific permit pathway is detailed below.
Two Harbors (Catalina Island) by the numbers
Rounded figures from the 2020 US Census, LA County Assessor parcel data, and LA County DPW permit records.
Population
200
2020 Census
Single-family homes
~70
LA County Assessor
Median lot size
5,000 sqft
Approximate
ADU permits filed 2025
~1
Source: HCD 2025 total (1,278) distributed proportionally across 2024 per-area shares. 2024: 1.
What makes Two Harbors (Catalina Island) different
Two Harbors is on the narrow 'isthmus' between Catalina Harbor and Isthmus Cove on Catalina Island's western half, 22 miles by ferry from the mainland. Year-round population is about 200; summer surges to 1,000+ with seasonal workers + visitors. Permits run through LA County DPW Building & Safety. Construction is logistically extreme, all materials ferried from the mainland, no road from Avalon. Most land on the island (88%) is owned by the Catalina Island Conservancy (private nonprofit), which restricts new construction.
LA County ADU rules for Two Harbors (Catalina Island)
Last verified: 2026-04-15
Current LA County rules from Title 22 of the County Code, as applied to Two Harbors (Catalina Island). State preemption (Gov Code §§ 66310-66342) means the county can't reduce below the state baseline. We note where that applies.
| Max detached ADU size | 1,200 sqft (state default) |
| Max ADU height | 16 ft / 18 ft with second-story setbacks |
| Setbacks | 4 ft side / 4 ft rear (state minimum) |
| Permitting agency | LA County Public Works (Building & Safety) |
| Catalina Island Conservancy | Owns 88% of the island; restricts new construction outside designated areas |
| Construction logistics | All materials ferried from mainland; no road from Avalon; ~30-50% construction-cost premium |
| Local processing time | 60 days from complete submittal (state-mandated) |
Active overlays + extra rules in Two Harbors (Catalina Island)
LA County overlays + state-level designations that hit a meaningful share of Two Harbors (Catalina Island) parcels.
California Coastal Zone
~100% of parcelsEntire island is in the Coastal Zone. Coastal Development Permit required.
Catalina Island Conservancy lands
88% of island owned by the Conservancy, new construction restricted to designated developable areas.
Watch-outs specific to Two Harbors (Catalina Island)
- 01
Construction logistics make Accessory Dwelling Units (ADUs) cost ~50% more
All materials ferry from the mainland (no road from Avalon to Two Harbors). Construction costs run 30-50% higher than mainland LA County equivalents. ADU economics rarely pencil unless owner-occupied.
- 02
Catalina Island Conservancy restricts new construction
88% of the island is owned by the Conservancy. Verify your parcel is in a designated developable area before any planning.
- 03
Coastal Development Permit required
Entire island is in the California Coastal Zone. CDP required from LA County DPW + potentially the California Coastal Commission for some categories.
Need a person, not a wizard?
Routes that fit Two Harbors (Catalina Island)
Based on what we know about Two Harbors (Catalina Island), these are the lead types that usually make sense here. Pick whichever fits your situation. All free, no obligation.
Complex permit context
Request a Two Harbors (Catalina Island) permit referral
Coastal, hillside, historic, fire-zone, or multi-overlay parcels in Two Harbors (Catalina Island) usually mean a permit expediter pays for itself in saved months. We work with affiliated Los Angeles permit expediters and expeditors (both spellings) who've handled Two Harbors (Catalina Island) projects.
Complex permit context
Request a Two Harbors (Catalina Island) permit referral
Coastal, hillside, historic, fire-zone, or multi-overlay parcels in Two Harbors (Catalina Island) usually mean a permit expediter pays for itself in saved months. We work with affiliated Los Angeles permit expediters and expeditors (both spellings) who've handled Two Harbors (Catalina Island) projects.
Amenities + civic services in Two Harbors (Catalina Island)
Parks, libraries, and the school district that serve the area. Context that matters for renter appeal, family relocation, and long-term resale.
Public schools
School assignments vary by exact address. Performance levels below are from the official California School Dashboard, California's official accountability system uses colored levels (blue highest, red lowest) rather than 1-10 numeric scores.
District
Long Beach Unified School District (LBUSD operates the one-room schoolhouse at Two Harbors)
Getting around Two Harbors (Catalina Island)
Car-restricted island community. Ferry from mainland; golf carts + bicycles on the island.
Transit + walkability
Walkability
Walkable within the small Two Harbors hamlet. No road network to Avalon.
Nearby airports
Distance + type for each major Los Angeles-area airport reachable from Two Harbors (Catalina Island). Useful for travel, commute, and any flight-path noise concerns on specific parcels.
Catalina Airport in the Sky (AVX)
~10 miGeneral aviation
Community + landmarks in Two Harbors (Catalina Island)
Annual events, landmarks, and the places that anchor the area's identity. Context for renter appeal and long-term resale.
What makes Two Harbors (Catalina Island) Two Harbors (Catalina Island)
Land conservancy
Catalina Island Conservancy
Private nonprofit owning 88% of Catalina Island. Controls most land-use decisions outside Avalon + Two Harbors residential areas.
Historic site
Two Harbors isthmus + Banning House
Originally developed by the Banning family in the early 1900s. The Banning House (1910) is the historic centerpiece.
Frequently asked questions about Two Harbors (Catalina Island) ADUs
›Can I build an ADU in Two Harbors (Catalina Island)?
Yes. Two Harbors (Catalina Island) allows ADUs under LA County Code Title 22, aligned with California Gov Code §§ 66310-66342. Most single-family lots can host one ADU plus one JADU. Permits go through LA County Public Works (Building & Safety), not LADBS, since Two Harbors (Catalina Island) is unincorporated territory rather than a city.
›Why does Two Harbors (Catalina Island) use LA County rules instead of LA City rules?
Two Harbors (Catalina Island) is unincorporated. It's never been formally incorporated as its own city, so LA County serves as the local government. Building permits, zoning, sheriff, libraries (in many cases), and most other services run through county departments rather than city ones.
›Where do I submit my Two Harbors (Catalina Island) ADU permit?
Online via LA County's EPIC-LA portal, or in-person at the LA County Public Works Building & Safety counter in Alhambra (900 S. Fremont Avenue). The EPIC-LA online portal handles most ADU submittals end-to-end, so you rarely need to visit in person.
›How long does the ADU permit process take in Two Harbors (Catalina Island)?
LA County DPW targets the state-required 60-day plan check for ADUs from a complete submittal. Hillside, VHFHSZ, or environmental-review parcels can extend timelines by 4 to 12 weeks. Two Harbors (Catalina Island)-specific overlays may add additional time. See the watch-outs above.
›Are LA County's pre-approved ADU plans free?
Yes. LA County maintains three pre-approved standard ADU plans (Plans A, B, and C) usable in any unincorporated area, including Two Harbors (Catalina Island). They're free to use, similar to LADBS's YOU-ADU program. The trade-off is reduced design flexibility, but for a fast, low-cost permit path they're the strongest option.
Ready to see what your Two Harbors (Catalina Island) lot can do?
Our free address checker pulls real zoning, overlay, and parcel data for any Los Angeles County address, including unincorporated Two Harbors (Catalina Island). Start there and we'll surface what applies to your specific lot.
Check your address →Reviewed by Yair Harpaz, Founder, PermitPathLA. California DRE-licensed broker with 30+ years of Los Angeles real estate and mortgage industry experience.
Two Harbors (Catalina Island) ordinance data last reviewed .
See an error or stale rule? corrections@permitpath.la
Primary sources: LA County DPW ADU info · LA County Code Title 22