ADU and JADU requirements, official sources, agencies, and permit information for properties located in unincorporated Los Angeles County. Properties inside an incorporated city are governed by that city’s local planning and permitting agencies.
Rules are grouped by topic. Open a topic for the answers, the conditions on them, and the official source each one came from. Each rule names the authority that set it: Statewide standard and Unincorporated Los Angeles County standard.
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54 rules
What can I build?
The kinds of accessory dwelling unit this jurisdiction recognises.12 rules
Detached ADU allowed
Allowed
Whether a detached, newly constructed ADU is permitted.
Set by: Unincorporated Los Angeles County standard
Allowed
Detached ADUs are authorized on the same lot as a proposed or existing primary dwelling.
Set by: Statewide standard
In force from: Effective
Where a topic is recorded at more than one level, both entries are shown with the authority that set them. Which one governs a particular property is a question for the responsible planning agency.
Explanation — Statewide standard
Whether a detached, newly constructed ADU is permitted.
Part of Statewide, published by California.
Source — Unincorporated Los Angeles County standard
Accessory Dwelling Units: Senate Bill 543 & Assembly Bill 1154, Los Angeles County Code, Title 22 — Page 11
Source document
Accessory Dwelling Units: Senate Bill 543 & Assembly Bill 1154
Publisher
Los Angeles County Department of Regional Planning
Document type
Planning bulletin
Source type
Official guidance
Code reference
Los Angeles County Code, Title 22
Section
22.140.640(E), Table 22.140.640-A
Page
11
Effective from
January 1, 2026
Source checked
August 13, 2026
Excerpt
One proposed or existing, legally-built single-family residence in any zone that allows residential use. 1 attached to or within a single-family residence or accessory structure, and 1 detached from residences
Whether an ADU attached to the primary dwelling is permitted.
Set by: Unincorporated Los Angeles County standard
Allowed
Attached ADUs are authorized.
Set by: Statewide standard
In force from: Effective
Where a topic is recorded at more than one level, both entries are shown with the authority that set them. Which one governs a particular property is a question for the responsible planning agency.
Explanation — Statewide standard
Whether an ADU attached to the primary dwelling is permitted.
Part of Statewide, published by California.
Source — Unincorporated Los Angeles County standard
Accessory Dwelling Units: Senate Bill 543 & Assembly Bill 1154, Los Angeles County Code, Title 22 — Page 11
Source document
Accessory Dwelling Units: Senate Bill 543 & Assembly Bill 1154
Publisher
Los Angeles County Department of Regional Planning
Document type
Planning bulletin
Source type
Official guidance
Code reference
Los Angeles County Code, Title 22
Section
22.140.640(E), Table 22.140.640-A
Page
11
Effective from
January 1, 2026
Source checked
August 13, 2026
Excerpt
One proposed or existing, legally-built single-family residence in any zone that allows residential use. 1 attached to or within a single-family residence or accessory structure, and 1 detached from residences
Whether converting existing space, such as a garage or interior area, into an ADU is permitted.
Set by: Unincorporated Los Angeles County standard
Allowed
Existing dwelling space and accessory structures, including garages, may be converted to ADUs.
Set by: Statewide standard
In force from: Effective
Where a topic is recorded at more than one level, both entries are shown with the authority that set them. Which one governs a particular property is a question for the responsible planning agency.
Explanation — Statewide standard
Whether converting existing space, such as a garage or interior area, into an ADU is permitted.
Part of Statewide, published by California.
Source — Unincorporated Los Angeles County standard
Accessory Dwelling Units: Senate Bill 543 & Assembly Bill 1154, Los Angeles County Code, Title 22 — Page 12
Source document
Accessory Dwelling Units: Senate Bill 543 & Assembly Bill 1154
Publisher
Los Angeles County Department of Regional Planning
Document type
Planning bulletin
Source type
Official guidance
Code reference
Los Angeles County Code, Title 22
Section
22.140.640(G)(1)(a)(ii)(1)(b)
Page
12
Effective from
January 1, 2026
Source checked
August 13, 2026
Excerpt
Entirely within an existing, legally-built single-family or multi-family residential building residence; or (ii) The result of the conversion of an existing, legally built accessory structure, with an expansion of not more than 150 square feet beyond the same physical dimensions of said structure, solely for the purpose of accommodating ingress and egress.
Set by: Unincorporated Los Angeles County standard
Allowed
JADUs are authorized on qualifying single-family residential lots with a proposed or existing single-family residence.
Set by: Statewide standard
In force from: Effective
Note: Conditions apply
Where a topic is recorded at more than one level, both entries are shown with the authority that set them. Which one governs a particular property is a question for the responsible planning agency.
Explanation — Statewide standard
Whether a junior ADU is permitted.
When this applies
Applies when all of the following are true:
Property primary structure type is Single family
Part of Statewide, published by California.
Source — Unincorporated Los Angeles County standard
Accessory Dwelling Units: Senate Bill 543 & Assembly Bill 1154, Los Angeles County Code, Title 22 — Page 11
Source document
Accessory Dwelling Units: Senate Bill 543 & Assembly Bill 1154
Publisher
Los Angeles County Department of Regional Planning
Document type
Planning bulletin
Source type
Official guidance
Code reference
Los Angeles County Code, Title 22
Section
22.140.640(E), Table 22.140.640-A
Page
11
Effective from
January 1, 2026
Source checked
August 13, 2026
Excerpt
One proposed or existing, legally-built single-family residence in any zone that allows residential use. 1 attached to or within a single-family residence or accessory structure, and 1 detached from residences
An ADU is a residential use consistent with the lot's existing general-plan and zoning designations where the lot allows single-family or multifamily residential use.
Explanation
Whether the zoning district permits ADUs.
Part of Statewide, published by California.
Source
California Government Code, Title 7, Division 1, Chapter 13, § Gov. Code § 66314(c)
Source document
California Government Code, Title 7, Division 1, Chapter 13
Connections, meters and the charges that come with them.7 rules · Statewide standard · Effective
Separate utility meter required
Not required
For qualifying conversion ADUs and JADUs, a new or separate direct utility connection may not be required except with a new single-family dwelling or separate conveyance.
Note: Conditions apply
Explanation
Whether the ADU must have its own utility meter.
When this applies
Applies when all of the following are true:
Project construction type is one of Interior conversion, Accessory structure conversion, Garage conversion
Part of Statewide, published by California.
Source
California Government Code, Title 7, Division 1, Chapter 13, § Gov. Code § 66311.5(d)
Source document
California Government Code, Title 7, Division 1, Chapter 13
A completed ADU or JADU application on a lot with an existing qualifying dwelling must be approved or denied within 60 days; applicant-requested delay tolls the period.
In force from: Effective
Note: Conditions apply
Explanation
Longest period the agency may take to approve or deny a completed application. Frequently scoped to lots with an existing dwelling; that condition belongs in the claim's applicability, not in this description.
When this applies
Applies when all of the following are true:
Property has existing primary dwelling is yes
Part of Statewide, published by California.
Source
California Government Code, Title 7, Division 1, Chapter 13, § Gov. Code §§ 66317(a)(3), 66335(a)(3)
Source document
California Government Code, Title 7, Division 1, Chapter 13
Maximum period to act on a coastal development permit
Up to 60 days
A completed coastal development permit application for an ADU must be approved or denied within 60 days, subject to the concurrent-primary-dwelling exception.
In force from: Effective
Note: Conditions apply
Explanation
Longest period the agency may take to act on a coastal development permit application. Separate from the underlying ADU application timeline.
When this applies
Applies when all of the following are true:
Property overlays includes Coastal overlay
Part of Statewide, published by California.
Source
California Government Code, Title 7, Division 1, Chapter 13, § Gov. Code § 66329(a)
Source document
California Government Code, Title 7, Division 1, Chapter 13
For a detached garage replaced by an ADU, written notice or placarding for demolition cannot be required outside an architecturally and historically significant historic district.
In force from: Effective
Note: Conditions apply
Explanation
Whether a demolition permit review or delay applies to the project.
When this applies
Applies when all of the following are true:
Property overlays does not include Historic district
Part of Statewide, published by California.
Source
California Government Code, Title 7, Division 1, Chapter 13, § Gov. Code § 66314(f)
Source document
California Government Code, Title 7, Division 1, Chapter 13
An ADU or JADU generally may not be sold separately from the primary residence, subject to a statutory separate-conveyance exception not captured by this broad rule.
Note: Conditions apply
Explanation
Whether the ADU may be sold separately from the primary dwelling.
When this applies
Applies when all of the following are true:
Project separate sale intended is yes
Part of Statewide, published by California.
Source
California Government Code, Title 7, Division 1, Chapter 13, § Gov. Code § 66314(d)(1)
Source document
California Government Code, Title 7, Division 1, Chapter 13
Who to contact in Unincorporated Los Angeles County
These agencies decide what is permitted here. Contacting them does not guarantee approval, but they can confirm what applies to a specific parcel.
Los Angeles County Department of Regional Planning
Administers zoning and land-use requirements, reviews ADU and JADU planning compliance, maintains the County ADU ordinance, and provides planning assistance.
ADUDesk summarises recorded rules for informational purposes and may not include every requirement. Confirm current requirements with the responsible planning agency before making design, purchase, or permit decisions.
About this information
Dates, versions and how rules are recorded
Rules are recorded from official sources and each one links to the document it came from. A source check confirms the document was retrieved and read; it is not a legal review, and the record may not cover every requirement that applies to a property or project.
Report as of
The date the rules on this page were resolved for.
Jurisdiction record reviewed
Not recordedWhen this jurisdiction's record was last checked. Not a legal review.
Statewide
Published by California
Rule-set effective from
Published
Statewide rules reviewed
A staff check of this rule set against its sources.
What changed in this version: Initial
Unincorporated Los Angeles County ADU and JADU Standards
Published by Unincorporated Los Angeles County
Rule-set effective from
Published
Local rules reviewed
A staff check of this rule set against its sources.
What changed in this version: Initial rule set
Planning an ADU in Unincorporated Los Angeles County?