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Compare ADU paths and jurisdictions.

Compare review authorities and project phases across up to 8 LA-area cities, then organize possible ADU starting paths without turning general guidance into a parcel decision.

Cities · 3 of 8

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§ I · Review path

Who reviews, and under what clock

Beverly Hills

Permit authority
City of Beverly Hills Community Development
Statutory decision clock
60 days after a complete application (Gov. Code §66317)
Utility reality
LADWP service upgrades common on pre-1970 panels — budget 8–12 wks.

Santa Monica

Permit authority
Santa Monica Planning & Building
Statutory decision clock
60 days after a complete application (Gov. Code §66317)
Utility reality
Coastal-zone parcels may trigger separate stormwater review.

Pasadena

Permit authority
Pasadena Permit Center
Statutory decision clock
60 days after a complete application (Gov. Code §66317)
Utility reality
Pasadena Water & Power generally faster than LADWP — 4–8 wks.

Permit and plan-check fees are set by each city and change on its own schedule — read the city's current published fee schedule, linked from its city desk page. Cost and rent depend on the specific parcel, not the city.

§ II · Unit footprints

By product type

Beverly Hills

Garage conversion
≈ 400 sq ft
Detached studio
480 sq ft
Detached 1-BR
750 sq ft
Detached 2-BR
1,000 sq ft

Santa Monica

Garage conversion
≈ 400 sq ft
Detached studio
480 sq ft
Detached 1-BR
750 sq ft
Detached 2-BR
1,000 sq ft

Pasadena

Garage conversion
≈ 400 sq ft
Detached studio
480 sq ft
Detached 1-BR
750 sq ft
Detached 2-BR
1,000 sq ft

Footprints RSA builds. Pricing is quoted per parcel after feasibility, not per city.

§ III · Timeline phases

Weeks per phase

Beverly Hills

Feasibility & survey
1–3 wks
Design & Title 24
4–8 wks
Permitting
see above
Foundation & framing
8–12 wks
MEP & finishes
10–14 wks
Inspections & closeout
2–3 wks

Santa Monica

Feasibility & survey
1–3 wks
Design & Title 24
4–8 wks
Permitting
see above
Foundation & framing
8–12 wks
MEP & finishes
10–14 wks
Inspections & closeout
2–3 wks

Pasadena

Feasibility & survey
1–3 wks
Design & Title 24
4–8 wks
Permitting
see above
Foundation & framing
8–12 wks
MEP & finishes
10–14 wks
Inspections & closeout
2–3 wks

Phases run in sequence. Permitting overlaps design on most projects.

City pages

Choose a starting path

Separate what you know from what still needs review.

Select only conditions you already know. Unknown is a useful answer: it keeps the right planning question in the brief instead of guessing.

Who has jurisdiction?
Is there a garage or other enclosed accessory structure?
How should the unit relate to the house?
Which site conditions are already known?

Project-preparation brief

Possible paths to investigate

Who has jurisdiction?
Unknown
Is there a garage or other enclosed accessory structure?
Unknown
How should the unit relate to the house?
Unknown
Which site conditions are already known?
Unknown

Possible paths to investigate

  • Detached ADU

    A possible starting point when a separate yard structure matches the household's intended relationship to the main home. Access, setbacks, utilities and mapped site conditions remain property questions.

    Review this service

  • Attached ADU

    A possible starting point when the new unit should connect to the main house. The connection can bring existing structure, circulation and building systems into the scope.

    Review this service

  • Garage conversion

    A possible starting point when an existing enclosure may be reused. Permit history, foundation, moisture, ceiling height, openings and utility routes still need review.

    Review this service

Questions still to answer

  • Which agency has land-use authority over the parcel? A mailing city alone does not answer this.
  • Is the garage or accessory structure permitted, and can its foundation, height and utilities support residential work?
  • Should the unit share a wall with the house, occupy separate yard space, or reuse an existing enclosure?
  • Do mapped hillside, fire, coastal, historic or overlay conditions apply, and where are utilities or septic located?

This organizes possible routes; it does not determine parcel eligibility, code compliance or permit approval.

Lot feasibility record

Resolve these facts before treating a path as feasible.

Keep each item unknown until a document, qualified professional or responsible agency resolves it.

  1. Property jurisdiction

    Which city or county has land-use authority? Confirm parcel boundaries rather than relying on the postal city.

    Confirm with: Planning or land-use agency

  2. Existing structures

    What is permitted today, and can the foundation, framing, moisture protection, ceiling height and openings support residential work?

    Confirm with: Building department and design team

  3. Setbacks and height

    Which statewide minimum protections and objective local standards apply to the selected ADU path?

    Confirm with: Planning and building departments

  4. Lot coverage, FAR and open space

    What do the parcel's calculations show, and does a statewide 800-square-foot safeguard affect the review?

    Confirm with: Planning agency

  5. Easements and recorded constraints

    Where are recorded easements, rights-of-way and other title constraints relative to the proposed footprint?

    Confirm with: Title record, surveyor and responsible agency

  6. Site and emergency access

    Can construction, occupants and emergency responders reach the proposed unit under the applicable standards?

    Confirm with: Building, fire and public-works agencies as applicable

  7. Fire, hillside, historic and other overlays

    Which mapped constraints or adopted plans apply, and what additional review or documents do they trigger?

    Confirm with: Planning, fire and other designated agencies

  8. Utilities, sewer or septic

    Where are existing connections, what capacity is documented and which provider must approve changes?

    Confirm with: Serving utility and environmental-health agency

  9. Responsible reviewing agency

    Who reviews land use, building plans and any separate clearances, and which current submission path does each require?

    Confirm with: Confirmed jurisdiction and its referral agencies

Sources checked: 2026-09-24

Open the jurisdiction guideOpen the official permit path

Preparation checklist · choose a jurisdiction

Beverly Hills, the City of Los Angeles and unincorporated county land are three separate permit paths with three separate counters. A city name in a mailing address does not decide which one you file under.

Municipal comparison

Find the counter before assembling the package.

This table compares one bounded question: how to identify the responsible authority and what each agency’s public guidance names for an initial ADU submission. It does not rank jurisdictions or decide parcel eligibility.

“First submission” means the documents explicitly named by the linked agency guidance, not every item that may be requested after site review. “Unknowns” are facts the cited material does not settle for a particular parcel.

City of Beverly Hills

Confirm authority
Confirm the parcel is inside Beverly Hills city limits; a Beverly Hills postal address alone is not proof.
Who reviews
Community Development directs applicants to consult Planning first; ministerial ADU review then occurs through building-permit plan check.
Documented first submission
For the city’s preapproved-plan path: a building permit application plus a site-specific package showing property lines, setbacks, easements, parking, utilities, sewer, drainage and emergency access. Custom projects must confirm their current checklist with Planning.
Still unknown
The cited checklist does not establish that a plan fits the parcel or identify every hillside, historic, fire or utility review.
Status and date basis
Current city guidance points to adopted BHMC Article 50. A June 2026 amendment discussed by the Planning Commission remains identified here as proposed, not enacted.

Official sources

City of Los Angeles

Confirm authority
Confirm the parcel is inside Los Angeles city limits; a neighborhood or postal city does not establish jurisdiction.
Who reviews
Los Angeles City Planning identifies zoning and overlay conditions; the Department of Building and Safety handles building-plan check and permitting.
Documented first submission
For the documented Standard Plan path: title sheet and area calculations, a site-specific plot plan and notes, and the approved ADU Standard Plan, submitted on sheets at least 11 × 17 inches. A custom design may require a different current checklist.
Still unknown
The checklist does not resolve coastal, hillside, fire, specific-plan, utility or prior-permit conditions, and it is not a parcel eligibility decision.
Status and date basis
ZA Memo No. 143 supersedes earlier city implementation guidance and incorporates state-law changes effective through January 1, 2025; the linked standard-plan checklist is a submission document, not a new ordinance.

Official sources

Unincorporated Los Angeles County

Confirm authority
Use County Planning’s Z-NET to verify the parcel is outside every city. White-masked areas in Z-NET are within a city and require that city’s information.
Who reviews
County Regional Planning reviews land use; County Public Works Building and Safety performs building-code plan check and permitting.
Documented first submission
The County guide calls for a Regional Planning base application, complete land-use application, full architectural set with site plan, floor plans and elevations, and property photographs through EPIC-LA.
Still unknown
The first package does not settle septic or well capacity, community standards districts, fire access, grading or the later agency-referral list.
Status and date basis
The cited submission guide is agency guidance. The separately cited County ADU ordinance amendment was adopted July 29, 2025 and effective August 28, 2025.

Official sources

Original comparison by RSA Development, synthesized from the linked public agency guidance.

Sources read September 23, 2026

Project-scope reference

Prepare a brief the agency can review.

Use this structure for Unincorporated Los Angeles County before commissioning drawings. It separates facts, decisions and unknowns; it does not determine eligibility or replace agency review.

Carry it into the printable checklist
Jurisdiction and parcel record
Put in the briefResponsible city or county, parcel profile, zoning and known overlays
Evidence boundarySave the dated lookup or agency record; a mailing city is not proof of jurisdiction.
Existing conditions
Put in the briefCurrent structures, permit history, property lines, easements, access and utilities
Evidence boundarySeparate what the public record shows from conditions that still need a survey, inspection or utility answer.
Proposed scope
Put in the briefDetached, attached or conversion path; intended use; rooms; access; parking and utility changes
Evidence boundaryDescribe the work being considered without calling it eligible, compliant or approved.
Additional review
Put in the briefHillside, fire, historic, coastal, grading, drainage, trees or private utilities when known
Evidence boundaryMark unknown conditions as questions for the named agency rather than assumptions.

Local source

This reference was checked against the Unincorporated Los Angeles County primary sources named in the checklist below. Last read: 2026-09-24.

Open official source

Publisher and method

RSA Development, based at 8484 Wilshire Blvd, Beverly Hills, CA 90211, publishes this reference. We read agency documents, record the date reviewed and link local claims to the source that supports them. We omit what we cannot verify and direct homeowners to confirm current rules with the agency.

RSA identity and location

Project preparation · Unincorporated Los Angeles County

What to settle before you file

A printable checklist for one jurisdiction. Nothing here is submitted to us, nothing is stored, and no sign-in is needed — tick what you have, print it, and take the rest to the counter.

Who this applies to

Land outside every city boundary in Los Angeles County — more than 120 communities, some of which use a neighbouring city's name in their mailing address. The county, not a city, is the planning department for these parcels.

Confirm this is your jurisdiction

Because the mailing address can name a city you do not file with, check the parcel in the county's jurisdiction lookup before anything else. If it comes back unincorporated, county standards apply and city standards do not.

LA County Planning — Find My Zoning

Who reviews what

  • LA County Department of Regional Planning

    Land-use approval. A Regional Planning base application is filed through the county's online system with a full architectural set, and the county states it reviews and approves or denies within 60 days of a complete application.

  • LA County Public Works — Building and Safety

    Building code plan check and permit, plus an agency referral sheet listing the other agencies whose sign-off is needed before the permit issues.

Local rule, and when it took effect

The statewide clock

Government Code § 66317 requires a written completeness determination within 15 business days. For a completed ADU application on a lot with an existing dwelling, the agency then has 60 days to approve or deny. A concurrent new primary dwelling may delay that decision, and applicant-requested delay tolls the period. These are decision rules, not an all-in permit guarantee.

Gov. Code § 66317 (California Legislative Information)
Scope decisions that add review

  • The 2025 amendment set a uniform 25-foot height limit for ADUs on properties with multifamily uses unless a community standards district imposes something tighter, and caps detached ADUs on those lots at 1,200 sq ft. Attached ADUs carry a uniform 1,200 sq ft limit.

  • The amendment allows statewide-exemption ADUs and JADUs described in Gov. Code § 66323 on lots in those zones regardless of vehicular access, to match state law. Fire-zone construction requirements still apply.

  • The amendment allows unpermitted structures to be converted to an ADU or JADU. That is a code path, not a shortcut: the structure still has to be brought to current standards.

  • An ADU of 800 sq ft or less may encroach into a required front-yard setback if it cannot be built anywhere else at ground level. It is an exception to argue with evidence, not a default.

Documents to gather

  • Print the result showing the parcel is unincorporated. It is the document that tells every consultant which rulebook applies.

  • The county asks for site plan, floor plans and elevations at land-use stage, plus photographs of the property. Incomplete sets do not start the clock.

  • Required even when a county pre-approved standard plan is used, because they are site specific.

Site conditions still unresolved

  • Many unincorporated parcels are not on public sewer. Capacity for an additional unit is an environmental health question, answered by testing, not by drawings.

  • Some communities carry their own standards that override the general county limits. Confirm whether one covers the parcel.

  • Building and Safety hands over a referral sheet naming the other agencies that must sign off. Until you hold it, the real sequence is unknown.

Practical next steps

  • Everything else on this list is wasted effort if the parcel turns out to be inside a city.

  • The county's own memo summarises what changed on 28 August 2025 and links the ordinance text.

  • The county publishes free pre-approved ADU standard plans. They cannot be revised, and each still needs a site-specific plot plan approved by Regional Planning.

Sources read · Sources last read September 24, 2026

Orientation for one parcel, not a determination. Rules change, and only the agency named above can tell you what applies to your address on the day you file. Nothing here promises that a permit will be approved.

Where to go next

Take a comparison into a specific scope.

Detached ADU serviceGarage conversion servicePermit path, phase by phaseCity research desks
Review my property

FAQ

How the comparison works

  1. How does the city comparison tool work?
    Pick two covered cities to compare jurisdiction, official agencies and planning context. The comparison is educational and does not replace address-specific review of zoning, overlays, utilities, fees or project eligibility.
  2. Where does the comparison data come from?
    The comparison uses cited public agency materials and the city-directory research model. Check each linked authority for current requirements; the tool does not present unsupported private-project pricing or review-time claims.
  3. Is one city always cheaper than another for the same ADU?
    Not always. Agency, consultant and utility costs can differ by jurisdiction and property. Confirm the current fee schedule and required reviews with the responsible authority rather than transferring a total from another city.
  4. Which California city issues ADU permits fastest in 2026?
    Review timing varies by agency workload, project completeness, utilities, and site overlays. Ask the relevant jurisdiction for its current published review targets before relying on a schedule.