Junior ADU (JADU)

Junior ADUs (JADUs) in Orange County: The Complete Guide

A JADU is a compact unit (up to 500 sq ft) carved from your existing home — the lowest-cost path to a legal rental or in-law space.

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A junior ADU is a small, self-contained unit created within your home’s existing walls — up to 500 sq ft, with its own entrance. It’s the lowest-cost way into a legal second unit. Here’s how it differs from a full ADU, what it costs, and the rules.

JADU vs ADU

A JADU is up to 500 sq ft and built within your home’s existing footprint, with its own entrance and an efficiency or shared kitchen. Unlike a full ADU, it carries an owner-occupancy requirement.

What it costs & who it suits

Because it reuses existing space, a JADU is typically the lowest-cost path to a legal unit — a good fit for a family suite or an affordable rental.

Permits & requirements

California’s JADU rules cover size, the kitchen, owner-occupancy and a recorded deed restriction. We handle the submittal and approvals.

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Why build with L Square

Design, permits and construction under one roof. L Square is a licensed Orange County design-build team (CSLB #1095476). One contract covers architecture, engineering, city approvals and our own build crews — so your ADU moves on a fixed schedule from first drawing to final inspection, across Orange County and Los Angeles.

01 · Architect-grade design: Every unit is drawn around your lot, light and privacy.
02 · Permit-ready, OC-savvy: We know each city’s ADU rules and clear the approvals for you.
03 · Built once, built right: Our own crews deliver on a fixed schedule, foundation to finishes.

Licensed · Insured · Bonded · CSLB #1095476 · Orange County & Los Angeles

Frequently asked questions

What’s the difference between a JADU and an ADU?

A JADU is up to 500 sq ft and built inside your home’s existing walls with an owner-occupancy rule; a full ADU can be larger, detached or attached, and has no owner-occupancy requirement.

How big can a JADU be?

Up to 500 sq ft, created within the existing footprint of your home.

Do I have to live on the property?

Yes — JADUs carry an owner-occupancy requirement, recorded as a deed restriction.

Can I have both a JADU and an ADU?

In many cases yes — California rules often allow a JADU and a separate ADU on the same single-family lot. We confirm what your city allows.

What does a JADU cost?

It’s usually the lowest-cost option because it reuses existing space; the figure depends on how much kitchen, bath and entry work is needed. We quote after seeing the space.

Building an ADU in your Orange County city

ADU rules vary by city — we handle the specifics for your address. Statewide, California allows ADUs up to about 1,200 sq ft with 4-ft side and rear setbacks (CA HCD); your city may add its own details. For the statewide rules, see the CA HCD ADU Handbook.

Irvine ADU rules Anaheim ADU rules Santa Ana ADU rules Huntington Beach ADU rules ADU cost guide All areas we serve

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your ADU?

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