Permitting · 7 min read · May 30, 2026 · 447 words
ADU vs JADU in California: the structural, legal, and cost differences
An ADU and a Junior ADU (JADU) sound similar but follow different rules for size, kitchen, owner-occupancy, and cost. A side-by-side breakdown so you pick the right one.
Key takeaways
- Pick a JADU if you want the cheapest possible permitted second unit, live on the property, and want to rent to a single person or couple long-term.
- Pick a garage conversion ADU if you want investor flexibility, full kitchen + bath, and lower cost than a new build.
- Pick a detached ADU if you want maximum rental yield, future-proof flexibility, and AB 1033 condo-sale optionality.
Answered in this guide
Jump straight to the question you came in with — every answer is on this page, with links onward to the deeper guide.
- What is SB-9 and does it apply to me?
- What about hillside or coastal lots?
- I'm in an HPOZ — can I still build?
- Do you handle the permitting?
- What setbacks and height limits apply?
- How long does an ADU project take in Los Angeles?
More across the studio · the full FAQ map · the reference desk
A JADU (Junior Accessory Dwelling Unit) is a smaller, more restricted cousin of a standard ADU. The two coexist under California Government Code §65852.22 (JADU) and §65852.2 (ADU) and a single-family lot can have one of each plus the primary house — three legal dwellings on one parcel. But the trade-offs are real, and the cheaper number on paper is not always the cheaper outcome.
Direct comparison
Maximum size
JADU: up to 500 sq ft. Standard ADU: 850 sq ft (studio/1BR) or 1,000 sq ft (2+ BR), and many cities allow up to 1,200 sq ft.
Location
JADU must be carved out of the existing primary residence (including an attached garage). ADU can be detached, attached, or a conversion.
Kitchen requirements
JADU is allowed an 'efficiency kitchen' — sink, cooktop (no oven required), under-counter fridge. ADU requires a full kitchen. This is the line that drives most of the structural cost gap.
Bathroom
JADU can share a bathroom with the primary house. ADU must have its own.
Owner-occupancy
JADU still requires owner-occupancy (the owner must live in the primary house or the JADU). ADU does NOT, after AB 976.
Permit fees
JADU: no impact fees. ADU under 750 sq ft: no impact fees. ADU 750+ sq ft: impact fees prorated by size.
Cost in real numbers
JADUs typically come in at $80,000–$160,000 because they reuse existing walls, foundation, roof, and most utilities. A garage-conversion ADU runs $120,000–$220,000 (see detached vs attached vs conversion). A detached new-construction ADU is $245,000+ in LA and $300,000+ in the Bay Area — see LA cost anatomy and Bay Area cost anatomy.
Rental income vs cost
JADUs rent at a discount — typically 60–75% of what a comparable ADU rents for — because the shared-wall layout and efficiency kitchen attract a smaller renter pool. For a long-term rental strategy, the ROI gap is smaller than the cost gap. See what an ADU actually rents for in LA and Bay Area ADU rent data for benchmarks.
Short-term rental
Because JADUs require owner-occupancy, they are essentially incompatible with full-time Airbnb hosting. Standard ADUs face their own city-by-city short-term rental rules — covered in our California ADU short-term rental guide.
Which one is right for you
- Pick a JADU if you want the cheapest possible permitted second unit, live on the property, and want to rent to a single person or couple long-term.
- Pick a garage conversion ADU if you want investor flexibility, full kitchen + bath, and lower cost than a new build.
- Pick a detached ADU if you want maximum rental yield, future-proof flexibility, and AB 1033 condo-sale optionality.
Sources
- California Government Code §65852.22 (JADU) · California Legislature
- HCD ADU & JADU Handbook · California HCD
Next chapter · 01 of 03
Design · 6 min read
Detached, attached, or conversion: choosing the right ADU type
Compare the JADU efficiency kitchen against full ADU build types in the build-type guide.
A decision framework for picking the configuration that fits your lot, budget, and rental strategy — with the trade-offs builders rarely volunteer.
FAQ · Permitting
Common questions on permitting
The questions readers send us most after this guide.
What is SB-9 and does it apply to me?
SB-9 (the California HOME Act) lets eligible single-family lots split into two parcels and/or add a duplex. We assess eligibility during the feasibility call — roughly 60% of LA single-family lots qualify on paper, fewer in practice once HPOZ, hillside, and coastal overlays are applied. SB-9 projects can stack with an ADU for up to four units on what was a single-family lot.What about hillside or coastal lots?
Hillside requires a Methane District review (where applicable) plus a haul route plan if grading exceeds 1,000 cubic yards. Coastal Zone projects (anything west of Lincoln Blvd in Venice, for example) need a Coastal Development Permit on top of standard LADBS approval. Both are workable; both add 60–90 days.I'm in an HPOZ — can I still build?
Yes, but with design review. Historic Preservation Overlay Zones require Certificate of Appropriateness from the cultural heritage commission before permits issue. We've shepherded projects through Miracle Mile, West Adams, Whitley Heights, and Spaulding Square HPOZs. Add 8–12 weeks for the COA process.Do you handle the permitting?
Yes. We file with LADBS or your local building department, manage plan check, coordinate utility upgrades, schedule inspections, and deliver final sign-off. You don't visit the counter, we do.What setbacks and height limits apply?
Statewide ADU law (AB 68/881) overrides most local restrictions: 4-foot side and rear setbacks, 16-foot height for detached one-story, 18-foot for two-story within ½ mile of transit. Front setbacks follow the underlying zone. We model your envelope at the schematic stage.How long does an ADU project take in Los Angeles?
Most detached ADUs run 9–13 months from contract to certificate of occupancy. Garage conversions are typically 4–6 months. Permitting alone is usually 60–120 days at LADBS depending on whether we use a pre-approved standard plan or a custom design that needs full plan check.
Reference desk · Permitting
More answers from the California reference desk
City-specific questions pulled from our 5,000-answer FAQ corpus — every link opens a deeper desk page.
How long does a ADU permit take in Beverly Hills?
City of Beverly Hills Community Development runs plan check 120–180 days on a complete, code-conformant submittal for a ADU. First-cycle approvals depend on three things: a stamped structural set, a Title 24 energy report bound into the package, and a site plan with verified setbacks. Most slippage comes from missing one of those three on first submittal.Why do ADU permits get rejected in Beverly Hills?
In Beverly Hills, the five most common first-cycle corrections are: (1) Title 24 energy compliance not bound to the submittal, (2) site plan setback math off by inches, (3) structural calcs not stamped by a CA-licensed engineer, (4) utility load calculations missing for the panel upgrade, and (5) drainage/grading not addressed for impervious-surface adds. Fixing all five before submittal cuts 120–180 days off the schedule.Does state ADU law override Beverly Hills rules for my ADU?
For qualifying ADU and JADU scopes, California Government Code §65852.2 and §65852.22 preempt most local discretionary review — Beverly Hills cannot impose owner-occupancy requirements (banned by AB 976), most parking minimums near transit, or stylistic design review. Local jurisdictions still control building-code application, Title 24, utility connection, and impact fee schedules. Non-ADU scopes (full additions, remodels, hillside builds) remain fully under local control.Are pre-approved standard plans available in Beverly Hills for a ADU?
Where Beverly Hills has adopted a pre-approved standard ADU plan program, using one cuts plan check by 30–60 days and removes the structural review fee. For programs that exist (LADBS, San Jose, San Diego), the trade-off is that floor-plan changes void the pre-approval. Most owners are better off using a standard plan as a starting point and accepting the layout it ships with.How long does a garage conversion permit take in Beverly Hills?
City of Beverly Hills Community Development runs plan check 120–180 days on a complete, code-conformant submittal for a garage conversion. First-cycle approvals depend on three things: a stamped structural set, a Title 24 energy report bound into the package, and a site plan with verified setbacks. Most slippage comes from missing one of those three on first submittal.Why do garage conversion permits get rejected in Beverly Hills?
In Beverly Hills, the five most common first-cycle corrections are: (1) Title 24 energy compliance not bound to the submittal, (2) site plan setback math off by inches, (3) structural calcs not stamped by a CA-licensed engineer, (4) utility load calculations missing for the panel upgrade, and (5) drainage/grading not addressed for impervious-surface adds. Fixing all five before submittal cuts 120–180 days off the schedule.Does state ADU law override Beverly Hills rules for my garage conversion?
For qualifying ADU and JADU scopes, California Government Code §65852.2 and §65852.22 preempt most local discretionary review — Beverly Hills cannot impose owner-occupancy requirements (banned by AB 976), most parking minimums near transit, or stylistic design review. Local jurisdictions still control building-code application, Title 24, utility connection, and impact fee schedules. Non-ADU scopes (full additions, remodels, hillside builds) remain fully under local control.Are pre-approved standard plans available in Beverly Hills for a garage conversion?
Where Beverly Hills has adopted a pre-approved standard ADU plan program, using one cuts plan check by 30–60 days and removes the structural review fee. For programs that exist (LADBS, San Jose, San Diego), the trade-off is that floor-plan changes void the pre-approval. Most owners are better off using a standard plan as a starting point and accepting the layout it ships with.How long does a JADU permit take in Beverly Hills?
City of Beverly Hills Community Development runs plan check 120–180 days on a complete, code-conformant submittal for a JADU. First-cycle approvals depend on three things: a stamped structural set, a Title 24 energy report bound into the package, and a site plan with verified setbacks. Most slippage comes from missing one of those three on first submittal.
Sources & further reading
- California Government Code §65852.2 — statewide ADU framework (ministerial review, 60-day clock).
- LADBS — Accessory Dwelling Unit information bulletins and current permit fee schedule.
- HCD — California Department of Housing & Community Development, ADU handbook (2024 update).
- Internal data: 120++ ADU projects delivered across Los Angeles County, 2018–2025.
Continue your read · the editorial path
We chained these chapters in the order LA homeowners actually need them. Each one picks up where the last one left a question open.
02 / 03
Permitting · 6 min
AB 976: California's permanent ban on ADU owner-occupancy requirements
AB 976 made the temporary ban on ADU owner-occupancy rules permanent starting January 1, 2025. Here is what changed, which exceptions remain, and why this matters for investors.
Read chapter →03 / 03
Cost · 9 min
The anatomy of an LA ADU build, line by line
Where every dollar of a $325,000 detached 800 sq ft ADU actually goes — soft costs, hard costs, contingencies, and the line items that surprise homeowners most.
Read chapter →
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