By David Petikyan · Property Provider Group | eXp Realty · Mission Hills, CA
Here’s a number every Granada Hills homeowner should know before building an ADU: 800.
That’s how many square feet of backyard home California says the City of Los Angeles must approve on a single-family lot, as long as it sits four feet from your side and rear lot lines.
So can you build an ADU in Granada Hills? Usually, yes. The details depend on your lot, your overlay and whether you’re up in the foothills. Let me break it down.
The rulesCan You Build an ADU in Granada Hills? What State Law Guarantees
Granada Hills is part of the City of Los Angeles. On a lot with a single-family home, state law guarantees three ADU types you can combine:
-
1A conversion
One ADU inside the house or a structure like a detached garage, which can grow 150 sq ft for an entrance.
-
2A junior ADU
Up to 500 sq ft inside the home, including an attached garage.
-
3A new detached ADU
Up to 800 sq ft, with four-foot side and rear setbacks.
- 800sq ft detached ADU
- 4 ftside and rear setbacks
- 16 fttypical height limit
- 60days to approve or deny
That last number matters. With a home already on the lot, the City must approve or deny a complete application within 60 days.
An ADU has no owner-occupancy rule. A junior ADU that shares a bathroom with the house does.
Your lotHow Granada Hills Lot Sizes Shape Your ADU Options
Based on Assessor records we analyzed for our Granada Hills neighborhood guide, the typical lot is about 7,700 sq ft south of the 118 and about 10,000 sq ft north of it.
An 800 sq ft cottage uses roughly a tenth of a 7,700 sq ft lot. Placement depends on trees, utilities, easements and yard space.
North of the 118, about half of lots are 10,000 sq ft or larger. More room, but also hillside rules.
Local wrinklesOverlays, Eichlers and Hillside Lots
Granada Hills has overlays you won’t find in most of the Valley:
-
Old Granada Hills RFA District
It caps house size tightly. But City Planning says it can’t block an 800 sq ft state-law detached ADU.
-
Balboa Highlands HPOZ
Same rule for the Eichler tract. Talk to City Planning early about design. No ADU parking is required in a historic district.
-
Fire and hillside lots
LA restricts its own “ordinance ADUs” on lots in both a Very High Fire Hazard Severity Zone and a Hillside Area. State-law ADUs aren’t subject to that.
My tip
Before you pay for plans, look up your parcel on ZIMAS. It shows your zone, overlays, and any fire hazard or hillside designation.
The moneyFees, Parking and Property Taxes
Construction bids vary a lot from yard to yard, so get two or three. Here are the other costs:
-
Impact fees
None under 750 sq ft. Above that, they’re proportional to the main house. School fees may apply over 500 sq ft.
-
Parking
None required within a half-mile walk of public transit. Converting a garage? You don’t have to replace its spaces.
-
Property taxes
The Assessor treats an ADU as new construction and adds its value to your current assessed value.
-
Plans
LADBS pre-approved standard ADU plans can shorten plan check.
Renting it out? State law lets cities require ADU rentals longer than 30 days, so check before planning short-term stays.
For sellersSelling a Granada Hills Home With an ADU
Here’s what matters most when you sell. Buyers and appraisers treat permitted and unpermitted space very differently.
Built a back unit or garage conversion without permits before January 1, 2020? Under AB 2533, the City generally can’t deny a permit for it just for code or ADU-rule issues, unless a fix is needed for health and safety. LADBS now has a streamlined process.
You can first get a confidential inspection from a licensed contractor. LADBS doesn’t require you to share the results with the City. Seller disclosures to buyers are a separate question, so ask your agent or attorney.
My office is on Devonshire Street in Mission Hills, a short drive away. My advice: pull the permit history on any ADU before you set a price.
Your local guide
David Petikyan
I lead Property Provider Group with eXp Realty from our office in Mission Hills, a short drive from Granada Hills. I’m also a California Association of REALTORS® Certified Probate & Trust Specialist.
Property Provider Group | eXp Realty · DRE# 02089725
15545 Devonshire St #103, Mission Hills, CA 91345 · (818) 394-0012
eXp Realty of Greater Los Angeles, Inc. #02188471 · Equal Housing Opportunity
Granada Hills ADU FAQ
Can I build an ADU in Granada Hills?
In most cases, yes. State law requires the City of Los Angeles to approve qualifying ADUs on single-family lots, including a detached ADU of up to 800 sq ft with four-foot side and rear setbacks.
How big can a Granada Hills ADU be?
A new detached state-law ADU can be up to 800 sq ft, usually 16 feet tall. A junior ADU inside the house can be up to 500 sq ft.
Will an ADU raise my property taxes?
Only for the new part. The LA County Assessor adds the ADU’s value to your existing assessed value.
Can I add an ADU in Balboa Highlands or the Old Granada Hills RFA District?
Usually, yes. City Planning says HPOZ and floor-area limits can’t shrink a state-law detached ADU below 800 sq ft.
More for Granada Hills Homeowners
Sources & notes
- California HCD, ADU Handbook (March 2026): ADU types, 800 sq ft and four-foot setbacks, 16-foot height, 60-day review, fees, parking, rental terms, owner occupancy and pre-2020 unpermitted ADUs.
- LA City Planning, ZA Memo 143, Revision 1: RFA and HPOZ limits, and the fire and hillside restriction.
- LADBS, Accessory Dwelling Unit page: ADU Ordinance 186,481, the Standard Plan Program and the AB 2533 bulletin.
- LA County Assessor, New Construction and Real Property pages: ADUs are assessable new construction, and that value is added to the existing assessed value.
- Granada Hills lot sizes: our analysis of LA County Assessor parcel data, published on our Granada Hills page. Figures are approximate.
Photos: 118 Freeway aerial: Brew Books, Wikimedia Commons, CC BY-SA 2.0 (resized). Eichler home: User “Los Angeles,” Wikimedia Commons, CC BY-SA 3.0 (resized, house number blurred). O’Melveny Park: Downtowngal, Wikimedia Commons, public domain. Agent photo: Property Provider Group.
Information is believed accurate but not guaranteed. ADU laws and fees change, so verify zoning, overlays, fees and permits with LADBS and City Planning for your parcel, and consult an attorney or CPA for advice on your situation. No MLS data is used in this post.