ADU (Accessory Dwelling Unit)
A self-contained second home on a residential lot, with its own kitchen, bath, and entrance.
An Accessory Dwelling Unit is a fully independent dwelling — kitchen, bathroom, sleeping area, and a separate entrance — built on the same lot as a primary residence. Under California state law (Gov. Code §65852.2), every single-family lot in the state must allow at least one ADU, capped at 1,200 sqft. Cities like Los Angeles, Long Beach, and Pasadena allow up to two ADUs (one ADU + one JADU) on most single-family lots.
ADUs can be detached new construction, attached additions, garage conversions, or carved out of existing space inside the main house. Detached ADUs typically cost $375–$650/sqft turnkey in Greater LA; garage conversions start around $165k for ~400 sqft.
Sources
Related terms
- JADU (Junior Accessory Dwelling Unit)An ADU up to 500 sqft carved out of an existing single-family home.
- AB 68 (Assembly Bill 68)2019 California law that streamlined ADU approvals and removed local barriers.
- SB 9 (Senate Bill 9)Law allowing duplex conversion and lot splits on most single-family parcels.
- LADBS (LA Dept. of Building & Safety)The City of LA's plan-check, permit, and inspection authority.
People also ask
FAQ — ADU (Accessory Dwelling Unit)
What does "ADU (Accessory Dwelling Unit)" mean in plain English?
A self-contained second home on a residential lot, with its own kitchen, bath, and entrance. Browse the full construction glossary for related terms.
Why does ADU (Accessory Dwelling Unit) matter for a California ADU or remodel?
ADU (Accessory Dwelling Unit) comes up in the zoning and land-use side of nearly every Greater LA and Bay Area project we touch. An Accessory Dwelling Unit is a fully independent dwelling — kitchen, bathroom, sleeping area, and a separate entrance — built on the same lot as a primary residence. Getting it right at design saves rework later — getting it wrong is one of the most common reasons permits stall. See how it lands in our five-phase process and the relevant field guides.
Where will I see ADU (Accessory Dwelling Unit) on my own project?
Most owners run into ADU (Accessory Dwelling Unit) during the design or plan-check phase — specifically inside schematic design or permit submittal. Your project manager flags it on the schedule, walks you through what the city expects, and confirms documentation is in place before the inspection that depends on it.
Does ADU (Accessory Dwelling Unit) cost extra?
Sometimes — depends on whether it adds scope (a report, a structural detail, a fee) or just a paperwork step. Anything cost-impacting is itemized in your contract or change order, never buried in the invoice. Sanity-check your number with the ADU cost calculator and the 2026 cost report.
Who at Alpha Dream handles ADU (Accessory Dwelling Unit)?
The project architect owns design-level decisions; the permit runner owns city interactions — see the California permit directory; the project manager owns field execution. You always know who to ask. Start a conversation on the contact page.
When does ADU (Accessory Dwelling Unit) typically come up in the project schedule?
Most often during permit submittal or early construction. The full sequence is on the process page.
Is ADU (Accessory Dwelling Unit) handled differently in LA vs the Bay Area?
Yes — local interpretation varies. The LA studio and Bay Area studio note the regional shifts on each city hub.
What documents prove compliance with ADU (Accessory Dwelling Unit)?
City-specific — the California permit directory lists the form set per jurisdiction. Field journal entries show what actually clears plan check.
Which trades or consultants own ADU (Accessory Dwelling Unit) on a typical job?
Architect, structural engineer, or Title 24 consultant — depends on the term. The process page maps roles across the five phases.
How does ADU (Accessory Dwelling Unit) affect the project budget?
Direct line item in the contract when it triggers a report, detail, or fee. Pricing bands are in the 2026 cost report.
Has ADU (Accessory Dwelling Unit) changed recently under California law?
California ADU and remodel law has shifted every legislative session since 2017. Material changes land first on the field journal; definitions update quarterly here.
Where can I read the underlying statute for ADU (Accessory Dwelling Unit)?
Each glossary entry cites the relevant Gov Code, building code section, or city bulletin. The permit directorylinks the source portals.
Which ADU type is ADU (Accessory Dwelling Unit) most relevant to?
Cross-references live on the ADU types index. The term often appears in detached ADU and JADU contexts most.
Can I send ADU (Accessory Dwelling Unit) questions to your team?
Yes — use the contact page. We add the most-asked questions to the site-wide FAQ monthly.
What's a related term I should also read after ADU (Accessory Dwelling Unit)?
Each entry cross-links 3–5 related terms. Browse the full set on the glossary index.
Plain EnglishOff-site · Leo replies tonight
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