Granny Flat

Granny Flats in Orange County

“Granny flat” is the everyday name for an ADU — a self-contained backyard home for family or rental income.

A granny flat is simply an ADU — a private, self-contained unit with its own entrance, kitchen and bath. People build them for aging parents, adult kids, or rental income. Here’s what one is, how it’s used, and what it takes to build.

What a granny flat is

It’s another name for an ADU — a complete second home on your property with a private entrance, full kitchen and bathroom, whether detached in the yard or attached to the house.

Common uses

Granny flats house aging parents close by with independence, give adult kids a first place, generate rental income, or serve as a quiet home office or studio.

Sizes, cost & permits

They range from compact studios to 1,200 sq ft. Cost scales with size and finishes; we handle the OC permit process and give you a firm quote for your lot.

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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

Is a granny flat the same as an ADU?

Yes — “granny flat” is the everyday term for an accessory dwelling unit. Same legal unit, same permits.

How much does a granny flat cost in OC?

It depends on size, type and finishes; a garage conversion or JADU is lower-cost, a custom detached unit is higher. We quote after seeing your property.

Can I rent it out?

Yes — a permitted granny flat is a legal dwelling you can rent long- or short-term, subject to your city’s rules.

How big can it be?

Up to 1,200 sq ft for a full ADU, with at least 800 sq ft widely permitted; the right size depends on your lot and budget.

How long to build?

Most run roughly 6–12 months from design through permits to move-in; garage conversions move faster.

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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