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)A smaller ADU carved out of the existing house, capped at 500 sqft, with owner-occupancy required.
- AB 682020 California law that streamlined ADU permits — 60-day clock, parking exemptions, ministerial review.
- SB 92021 California law allowing ministerial lot splits and duplexes on most single-family lots.
- LADBS (LA Department of Building and Safety)The City of Los Angeles agency that issues building permits and conducts inspections.
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.
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.
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. 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.
Who at Alpha Dream handles ADU (Accessory Dwelling Unit)?
The project architect owns design-level decisions; the permit runner owns city interactions; the project manager owns field execution. You always know who to ask.