LA ADU and permit terminology glossary: 50+ terms LADBS, Title 24, and California state law actually mean

LA permitting has its own vocabulary. LADBS, LAMC, Title 24, ePlanLA, ZIMAS, JADU, PRADU, VHFHSZ. This page defines every term you'll encounter from feasibility through Certificate of Occupancy, with citations to the underlying source documents. Bookmark it.

Most-asked terms to know first: ADU (the unit itself), JADU (the smaller in-house version), PRADU (pre-approved plans that speed up permitting), School impact fee (the 750 sqft threshold that drives sizing decisions), and VHFHSZ (the fire-zone overlay that adds time and cost). Jump to each via the section letter.

A

AB 68 (2019) Assembly Bill 68, signed September 2019. The foundational California state law removing major local barriers to ADUs. Eliminated owner-occupancy requirements for new ADUs, preempted lot-size minimums and parking requirements within half a mile of major transit, and forced cities to approve ADU applications by-right. Codified at California Government Code §65852.2.

AB 332 (2023) Assembly Bill 332, signed October 2023. Amended state ADU law to require ministerial approval within 60 days, capped permit fees on smaller ADUs, and clarified that cities cannot reject ADUs solely because of nonconforming primary dwellings. Effective January 1, 2024.

AB 671 (2019) Assembly Bill 671. Created the state ADU amnesty program allowing legalization of unpermitted dwelling units constructed before January 1, 2018. In LA, administered through LADBS via specific submittal channels with reduced corrections.

AB 1033 (2023) Assembly Bill 1033. Authorized cities to permit ADUs to be sold separately from the primary dwelling as condominium units. LA has not yet opted in as of 2026; participation is local. Where opted in, the ADU becomes a separately-deeded condo.

AB 2221 (2022) Assembly Bill 2221. Clarified setback requirements for ADUs (4 feet from side and rear lot lines, with state preemption of larger local setbacks), addressed front-yard ADUs, and tightened time limits on city review.

ADU (Accessory Dwelling Unit) A secondary residential unit on a parcel that already contains a primary dwelling. Per California Government Code §65852.2, every California single-family lot is entitled to at least one ADU plus one JADU regardless of local zoning. In LA, detached ADUs are capped at 1,200 sqft; ADUs over 750 sqft trigger LAUSD school impact fees. See how to get an LA ADU permit.

Alquist-Priolo Earthquake Fault Zone A state-designated zone requiring a 50-foot setback from active seismic-fault traces before any habitable structure can be built. Established by the Alquist-Priolo Earthquake Fault Zoning Act of 1972 (California Public Resources Code §2621-2630). In LA, applies to portions of the Newport-Inglewood, Santa Monica, Hollywood, and Verdugo fault traces. See Alquist-Priolo ADU guide.

B

Bay Counter LADBS's in-person submittal and counter-service area at the downtown LA office (201 N. Figueroa St.) and regional offices. Walk-up alternative to the PermitLA online portal. Same-day plan check is available at the Bay Counter for PRADU and YOU-ADU submissions when scheduled.

BSO (Building Standards Code Order) A formal order issued by LADBS instructing a property owner to correct a code violation. Often follows a complaint inspection or discovery of unpermitted work. Failure to comply escalates to citations, fines, and eventually a stop-work or cease-and-desist order.

Building permit The primary LADBS permit authorizing construction of habitable structures. Issued after plan check approval and final fee payment. Required for ADUs, additions, remodels, and new construction. Sub-permits for plumbing, electrical, and mechanical (M/E/P) are typically issued alongside.

C

CALGreen (California Green Building Standards Code) California Title 24 Part 11. Mandatory green-building standards covering water efficiency, indoor air quality, material conservation, and electric-vehicle infrastructure. Applies to new construction including ADUs.

Cal HCD (California Department of Housing and Community Development) The state agency overseeing housing law compliance, including ADU law enforcement against non-compliant cities. Publishes the Annual Progress Report (APR) tracking ADU permits issued per city. Also certifies factory-built ADUs that bypass local plan check.

CBC (California Building Code) California Title 24 Part 2. The structural and life-safety code governing commercial and multi-family construction. ADUs over 4 units fall under CBC; smaller residential ADUs use CRC.

Cease and desist A formal LADBS order to stop work immediately. Issued when work is occurring without a permit, when permit conditions are violated, or when an inspection reveals unsafe construction. See LA cease-and-desist guide.

Certificate of Occupancy (CofO) The final document LADBS issues after the final building inspection passes, declaring the structure legally habitable. Required before renting out an ADU or selling the property with the new structure. Issued 1-2 weeks after final inspection.

Coastal Zone The state-defined Coastal Zone administered by the California Coastal Commission (CCC). Triggers additional review for any development. In LA, includes Malibu, Pacific Palisades, Venice, and Playa del Rey. Projects within the Coastal Zone often require a Coastal Development Permit in addition to LADBS approval. See Coastal Zone ADU guide.

Cover sheet The first page of a permit plan set. Contains property information, zoning, applicable overlays, scope of work, sheet index, code analysis, and disclosures. LADBS rejects plan sets with incomplete cover sheets.

CRC (California Residential Code) California Title 24 Part 2.5. The structural and life-safety code governing detached one- and two-family dwellings and townhouses up to three stories. Standard governing document for most residential ADUs in LA.

CSLB (Contractors State License Board) The California state board licensing contractors. Required for any contractor performing work valued over $500. LA homeowners can verify CSLB license status at cslb.ca.gov. Bus & Prof Code §7027.1 governs referral fees and advertising involving CSLB licensees.

D

DRE (California Department of Real Estate) The state agency licensing real estate brokers and salespersons. Required for any party representing a buyer or seller in a California real estate transaction. PermitPathLA's founder Yair Harpaz holds an active CA DRE license.

E

ePlanLA LADBS's online plan submittal system. Replaces in-person paper submittal for most permit types. Submitters upload PDF plan sets, pay fees, and track plan check progress through ePlanLA. The PermitPathLA wizard's submittal step produces ePlanLA-ready PDFs.

Express plan check LADBS's expedited plan check for projects meeting specific eligibility criteria (typically: PRADU or YOU-ADU plans with no overlay complications). Same-day or 5-business-day turnaround instead of the 60+ days standard plan check takes. See express plan check guide.

F

FAR (Floor Area Ratio) The ratio of total floor area of a building to its lot area. Used by LA zoning to cap how much square footage can be built on a given lot. ADUs do not count against FAR in LA per state preemption (AB 68).

G

Grading permit A separate LADBS permit required when site work involves moving more than 50 cubic yards of earth, or any grading on hillside parcels regardless of volume. Costs $1,500-$4,000 in 2026. Required for many ADU projects on sloped lots.

H

HCD-approved factory-built ADU A factory-built ADU certified directly by Cal HCD as meeting state building standards. Skips most local LADBS plan check because the unit is pre-certified. Only site work (foundation, utility connections, setbacks) requires permits. Companies in this category serving LA include Connect Homes, ABODU, and Welcome Projects.

HERS rater (Home Energy Rating System) A certified third-party inspector who verifies Title 24 Part 6 energy compliance. Required at multiple points during ADU construction (typically duct leakage, refrigerant charge, building envelope). HERS verification fees range $400-$900 per project.

Hillside Ordinance (Baseline Hillside Ordinance) LA's specific regulations for development on hillside parcels. Adds requirements around grading, foundation engineering, retaining walls, drainage, and street access. Hillside designations trigger longer plan check times (typically 90-120+ days). Codified at LAMC §12.21 C.10.

HPOZ (Historic Preservation Overlay Zone) LA's designation for neighborhoods of historic architectural significance. Adds a separate Cultural Heritage Commission review on top of standard LADBS plan check. Setbacks, materials, and design elements must be compatible with the HPOZ character. See HPOZ ADU guide.

I

Inspection milestone A specific construction stage at which LADBS conducts an inspection before work can continue. ADUs typically require 10 inspections: foundation, underground plumbing, rough framing, rough M/E/P, insulation, drywall, lath, final framing, final M/E/P, and final building.

Information Bulletin (LADBS IB) LADBS's primary policy and procedure documents. Each Information Bulletin (numbered, e.g. P/BC 2020-079) addresses a specific code interpretation, submittal requirement, or enforcement procedure. Considered the authoritative source for LADBS practice.

J

JADU (Junior Accessory Dwelling Unit) A subordinate unit within an existing single-family dwelling, no larger than 500 sqft, with an efficiency kitchen and shared bath access to the primary dwelling. Owner-occupancy required on one of the two units. Codified at Government Code §65852.22. JADUs do not count against ADU allowances; a lot can have one ADU plus one JADU.

L

LADBS (Los Angeles Department of Building and Safety) The City of LA agency administering building permits, plan check, inspections, and code enforcement for properties within the City of Los Angeles. Headquarters at 201 N. Figueroa St., downtown LA. Independent cities and unincorporated LA County areas use their own departments (see LA jurisdiction guide).

LAHD (LA Housing Department) The City of LA department handling rent-stabilization registration, tenant protections, and the LA rental housing inventory. ADUs intended for rental must register with LAHD post-construction.

LAMC (Los Angeles Municipal Code) The municipal code governing the City of LA. Chapter 1 covers zoning (LAMC §12.00-13.20). Chapter 9 covers building (LAMC §91.0101 onward). The ADU sections are LAMC §12.22 A.33 (state-conforming ADU rules) and §12.24 W.43 (administrative procedures).

Lateral system / shear wall The structural system that resists earthquake and wind loads. Reviewed by LADBS Building (Structural) during plan check. Shear walls are vertical wall sections sheathed with plywood or OSB and nailed per a specific schedule to transfer lateral forces to the foundation.

Liquefaction Zone A state-designated zone where soil conditions could fail during seismic shaking. Requires geotechnical investigation and may require deeper or pile foundations. In LA, includes large portions of the Valley floor and the LA Basin. Triggers added engineering scope and cost on most ADU projects.

M

Manual J / Manual S / Manual D The HVAC sizing calculations referenced by Title 24 Part 6. Manual J calculates heating and cooling loads; Manual S sizes equipment to match; Manual D sizes the duct system. Required submittal for any ADU with conditioned air.

Methane Zone (Methane Hazard Zone) A City of LA designation for parcels overlying former oil fields or methane-producing soils. Requires methane barriers and ventilation systems in foundations. Adds $5,000-$25,000 to construction depending on the zone classification. Concentrated in the area south of the 10 Freeway.

N

NavigateLA The City of LA's GIS map portal showing zoning, parcels, overlays, capital projects, public works, environmental layers, and dozens of other planning datasets. Free public tool at navigatela.lacity.gov. See NavigateLA tutorial.

O

Owner-occupancy requirement The historical rule (pre-AB 68) that an owner had to live in either the primary dwelling or the ADU. Removed by California state law for new ADUs permitted between January 1, 2020 and January 1, 2025, then permanently for new ADUs going forward under subsequent legislation. JADUs still carry the owner-occupancy requirement.

P

PermitLA LADBS's permit-management portal where homeowners and licensed contractors apply for permits, track plan check status, and pay fees. Separate from ePlanLA (which handles plan submittal). Free public account creation at dbs.lacity.gov.

Plan check LADBS's formal review of permit applications and plan sets. A pipeline of up to 10 specialist reviewers (zoning, building, mechanical, electrical, plumbing, fire, green, energy, plus optional engineering and specific-authority reviewers). See LADBS plan check pipeline.

Plan check corrections Specific deficiencies LADBS identifies during plan check that must be addressed before approval. Each correction round takes 1-3 weeks for designers/architects to respond. Most ADU projects see 1-3 rounds.

Plot plan / site plan The drawing showing the property boundary, existing structures, proposed structures, setbacks, easements, utility runs, and topography. Required component of every LADBS permit submittal. ADU site plans typically show the ADU footprint with dimensioned setbacks from all property lines.

PRADU (Permit Ready ADU) LADBS's pre-approved designer-firm ADU plans. ~80 plans (numbered ADU1 through ADU96) from licensed designer firms are pre-vetted by LADBS. License fee $2,000-$8,000 per plan. Same-day plan check available because the design is pre-approved. Browse at /standard-plans.

R

RID fee (Residential Impact Development fee) An LA development impact fee assessed on residential construction including ADUs over a specific size threshold. Used for parks, libraries, and infrastructure. Schedule varies by Council District.

R1 zone The most common LA single-family residential zone. Permits one primary dwelling plus one ADU plus one JADU by-right per state preemption. Most LA homeowners exploring ADUs live in R1 zones. See LA zoning codes that allow ADUs.

R2, R3, RD1.5 zones LA multi-family residential zones. Permit more units than R1, with ADU allowances scaling accordingly. RD1.5 (one unit per 1,500 sqft of lot area) is common in inner LA neighborhoods like Mid-City.

S

Setback The minimum distance a structure must be kept from a property line or other reference feature. State law (AB 2221) preempted larger local setbacks for ADUs, setting a maximum of 4 feet from side and rear lot lines. Front-yard setbacks remain governed by underlying zoning unless the ADU is small enough to qualify for state preemption.

School impact fee (LAUSD) The fee LAUSD assesses on new residential construction within the LA Unified School District boundary. As of 2026, $4.79 per habitable square foot. Triggered on ADUs larger than 750 sqft. ADUs under 750 sqft are exempt per state law.

Specific Plan A geographic-specific land-use plan adopted by LA City Council overriding base zoning in a defined area. Examples include Mulholland Scenic Parkway, Venice, Warner Center, Hollywood. Projects within a Specific Plan area require additional review against the Specific Plan's standards. See Mulholland Specific Plan guide.

Standard plan Either a YOU-ADU (free, city-published) or a PRADU (licensed designer-firm plan). Both are pre-approved by LADBS, enabling faster plan check than custom designs.

Stop work order A formal LADBS order halting construction immediately. Issued for unpermitted work, expired permits, or unsafe conditions. Triggers re-inspection and corrections before work can resume.

T

Title 24 The California building code suite, organized into 12 parts. Most-cited for residential construction: Part 2 (CBC), Part 2.5 (CRC), Part 4 (CMC mechanical), Part 5 (CPC plumbing), Part 6 (CEnC energy), Part 9 (CFC fire), Part 11 (CALGreen). The "Title 24 form" homeowners encounter is typically the Part 6 energy compliance document.

Title sheet See cover sheet.

V

VHFHSZ (Very High Fire Hazard Severity Zone) A state and local designation for areas with elevated wildfire risk. Triggers Fire Department review with stricter requirements for fire-resistant materials, defensible-space clearances (typically 100 ft), and access road dimensions. Concentrated in LA's hillside neighborhoods and canyon areas.

Y

YOU-ADU The City of LA's free pre-approved 455 sqft 1-bed/1-bath detached ADU plan. Three exterior style options (White, Charcoal, Spanish, Craftsman). Genuinely free to use, though site-specific preparation still costs $2,000-$6,000. See YOU-ADU standard plan reference.

Z

ZIMAS (Zoning Information & Map Access System) The City of LA's parcel-level zoning lookup tool. Free public access at zimas.lacity.gov. Reports zone, lot dimensions, applicable overlays (HPOZ, VHFHSZ, Methane, Coastal, etc.), Council District, and existing permit history per address. See ZIMAS tutorial.

Zoning The land-use classification assigned to each parcel by LA City Planning (or the relevant jurisdiction). Determines what can be built, including ADU eligibility. The PermitPathLA wizard's feasibility step looks up zoning automatically from ZIMAS data.

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This glossary is current as of May 2026. LA permitting law and LADBS procedures evolve. Specific fee amounts, code-section numbers, and policy details change at least annually. Each entry cites the underlying source document (LAMC section, LADBS Information Bulletin, or California code citation). Treat this page as a starting reference, not a substitute for verifying current rules with LADBS or your jurisdiction's building department before making project decisions. For terms that have their own dedicated guides, the deeper explanation lives at the linked page; the glossary entry stays definitional.

Missing a term? Email hello@permitpath.la and we'll add it.