Same zip, different jurisdiction: this page covers LA County Public Works (DPW). The same zip code(s) also cover parts of Santa Clarita (Santa Clarita (its own permits)). Verify your parcel's jurisdiction before filing, different agencies, different rules.
Antelope Valley · LA County (Unincorporated)
ADU permits in Green Valley
Zip codes:91390
Green Valley is a small rural unincorporated community of about 1,100 people in the western Antelope Valley, between Lake Hughes and the Angeles National Forest. It is not a city. Building permits run through Los Angeles County Public Works (Building & Safety).
Unincorporated LA County, not LADBS
Green Valley 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 Green Valley-specific permit pathway is detailed below.
Green Valley by the numbers
Rounded figures from the 2020 US Census, LA County Assessor parcel data, and LA County DPW permit records.
Population
1,100
2020 Census
Single-family homes
~420
LA County Assessor
Median lot size
45,000 sqft
Approximate
ADU permits filed 2025
~5
Source: HCD 2025 total (1,278) distributed proportionally across 2024 per-area shares. 2024: 6.
What makes Green Valley different
Green Valley borders Angeles National Forest. Multi-acre forested lots on septic + private wells. Permits run through LA County DPW Building & Safety at the Lancaster field office.
LA County ADU rules for Green Valley
Last verified: 2026-04-15
Current LA County rules from Title 22 of the County Code, as applied to Green Valley. 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), Lancaster field office |
| Fire-hazard construction | Chapter 7A required (universal VHFHSZ) |
| Local processing time | 60 days from complete submittal (state-mandated) |
Active overlays + extra rules in Green Valley
LA County overlays + state-level designations that hit a meaningful share of Green Valley parcels.
Very High Fire Hazard Severity Zone (VHFHSZ)
~98% of parcelsUniversal. Forest-edge wildfire exposure is significant.
Watch-outs specific to Green Valley
- 01
Forest-edge wildfire exposure
Green Valley borders Angeles National Forest. Wildfire exposure has been historically high. Chapter 7A + extensive defensible space are non-negotiable.
Need a person, not a wizard?
Routes that fit Green Valley
Based on what we know about Green Valley, these are the lead types that usually make sense here. Pick whichever fits your situation. All free, no obligation.
Complex permit context
Request a Green Valley permit referral
Coastal, hillside, historic, fire-zone, or multi-overlay parcels in Green Valley 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 Green Valley projects.
Complex permit context
Request a Green Valley permit referral
Coastal, hillside, historic, fire-zone, or multi-overlay parcels in Green Valley 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 Green Valley projects.
Amenities + civic services in Green Valley
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
Saugus Union School District + William S. Hart Union High School District
Getting around Green Valley
Car-only rural.
Transit + walkability
Walkability
Not walkable.
Nearby airports
Distance + type for each major Los Angeles-area airport reachable from Green Valley. Useful for travel, commute, and any flight-path noise concerns on specific parcels.
General William J. Fox Airfield (WJF, Lancaster)
~20 miGeneral aviation
Nearby areas to Green Valley
Other Los Angeles-area pages worth a look. Each one runs different Accessory Dwelling Unit (ADU) rules depending on jurisdiction, we show you what changes when you cross a city or county line.
LA County unincorporated
Lake Hughes →
Tiny western AV mountain-foothill unincorporated community. Multi-acre rural lots + LA County jurisdiction + VHFHSZ + AP fault-zone shape the Accessory Dwelling Unit (ADU) construction context.
LA County unincorporated
Elizabeth Lake →
Small western AV unincorporated community on the San Andreas Fault. Multi-acre rural lots + LA County jurisdiction + VHFHSZ + AP fault-zone shape the Accessory Dwelling Unit (ADU) construction context.
LA County unincorporated
Leona Valley →
Small western AV unincorporated community with cherry-orchard heritage. Multi-acre lots + LA County jurisdiction + San Andreas Fault zone shape the Accessory Dwelling Unit (ADU) calculus.
Frequently asked questions about Green Valley ADUs
›Can I build an ADU in Green Valley?
Yes. Green Valley 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 Green Valley is unincorporated territory rather than a city.
›Why does Green Valley use LA County rules instead of LA City rules?
Green Valley 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 Green Valley 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 Green Valley?
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. Green Valley-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 Green Valley. 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 Green Valley lot can do?
Our free address checker pulls real zoning, overlay, and parcel data for any Los Angeles County address, including unincorporated Green Valley. 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.
Green Valley 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