Greenlight
Guides

Can I build an ADU in a Very High Fire Hazard Severity Zone in Granada Hills?

Yes, in most cases. Los Angeles bars its own larger "Ordinance" ADUs only on lots that sit in both a Very High Fire Hazard Severity Zone and a Hillside Area, and the city says that bar may not be enforced on state-law ADUs: a detached backyard house up to 800 square feet, a conversion of existing space such as a garage, or a junior ADU inside the house 1234. What the fire zone does change is how you build. Expect fire-resistant materials under Chapter 7A, a Fire Department access review on deep lots, and sprinklers only if your main house already needs them 567.

Edited by Ryan Rambo, construction managerFacts checked 2026-10-08

How many Granada Hills homes are in the fire zone?

About one in six. We matched every single-family parcel in ZIP 91344 that sits inside the City of Los Angeles against the city's Very High Fire Hazard Severity Zone map, and 2,152 of 13,337 parcels touch the zone, which is 16% 8.

Treat that as a floor, not a final count. The city map layer we used was last edited in 2019. On March 24, 2025, CAL FIRE issued new recommended fire hazard maps for Los Angeles, and the Los Angeles Fire Department said it expects more parcels to be affected 9. A lot that was outside the zone when you bought it may be inside it now or soon.

The zone has not stopped Granada Hills from building. The city issued 174 ADU and junior ADU building permits in 91344 in 2024, 210 in 2025 and 157 in 2026 through Oct. 4, which made it the second-busiest ADU ZIP in the Valley 10.

What is the difference between a state-law ADU and an Ordinance ADU?

Los Angeles runs two sets of ADU rules side by side. State law guarantees a few kinds of ADU that the city has to approve, and the city's own ADU ordinance offers larger options with more conditions attached. City Planning's guidance says the two must be enforced separately 11.

The state-law ADUs that matter for a Granada Hills house are these:

The city's larger option is the detached Ordinance ADU, which City Planning's table lists at up to 1,200 square feet and two stories 12. That bigger unit is the one the fire-zone rule reaches.

Can I build an ADU if my lot is in both a fire zone and a Hillside Area?

Yes, if you build a state-law ADU. The city code prohibits ADUs on lots in both a Very High Fire Hazard Severity Zone and a Hillside Area except in a few listed cases, but City Planning's August 2025 guidance says that restriction may not be enforced on state-law ADU types 1.

In practice this means a lot in both zones can still get an 800-square-foot detached backyard house, a garage conversion, or a JADU 1234. The larger Ordinance ADU is the one at risk. If an Ordinance ADU does qualify for an exception, the city can still require public improvements to meet a 20-foot-wide street frontage rule 13.

The state housing department has pushed back on the prohibition itself. In a November 2024 letter, it told Los Angeles that the city had not shown ADUs would harm public safety in the fire zone and must either remove the prohibition or justify specific areas by resolution 14. As of the August 2025 guidance, the city still lists Ordinance ADUs as subject to it, so plan around it until that changes 1.

Hillside Area is its own map, separate from the fire map 15. Plenty of fire-zone lots are not in it.

Check your own lot, free.

Put in your address and see your zoning, lot size, fire and hillside zones, sewer distance and what is already built, from the city's own records.

Get my free Lot Snapshot →

What if my lot is in the fire zone but not a Hillside Area?

Then the both-zones prohibition does not apply, because it only reaches lots that are in both 1. You can choose a state-law ADU or an Ordinance ADU under that ADU's own rules.

The building standards still apply either way. Those are set by where the building sits, not by which ADU path you pick, and they are covered in the next section 5.

What does building in a fire zone add to my ADU?

Mostly materials and access, and sometimes sprinklers. These are the three things to budget and plan for:

  1. Chapter 7A materials. LADBS plan check tells applicants in the zone to comply with the materials, systems and construction methods of Chapter 7A 5. The purpose of that chapter is to help a building resist the intrusion of flames and burning embers from a vegetation fire, so it governs things like roofing, attic and eave vents, siding, windows and doors 16.
  2. Fire Department access. For new construction valued at $50,000 or more, if any part of the building is 150 feet from the edge of an improved street or approved fire lane, you need clearance from the Fire Department's Hydrants and Access Unit 6. Deep Granada Hills lots with a backyard house at the rear are the usual case.
  3. Sprinklers only if the house has them. State law says an ADU cannot be required to have fire sprinklers when the main house was not required to have them, and building the ADU does not trigger sprinklers in the main house 7. LADBS does require them in the ADU if the existing house already has a sprinkler system 17.

None of this stops a project, but each item changes the all in number, and the access question can move where the backyard house goes.

How do I check whether my own lot is in the fire zone?

Look it up in two places, because the city map and the state's newer map may not match yet.

  1. ZIMAS, the city's parcel lookup. Go to ZIMAS, search your address, and read the rows for Very High Fire Hazard Severity Zone and Hillside Area in the parcel report. The city's fire zone boundaries are set by the Los Angeles Fire Department under state law 18.
  2. CAL FIRE's 2025 map. The Fire Department points residents to an online comparison of the old and new maps 9. State law requires Los Angeles to adopt the recommended maps by ordinance, and the city may not lower a hazard level the state recommends 9. We could not find a record of the city's final adoption as of October 2026, so if the new map shows your lot in the zone, plan as if it is.
  3. Write down both answers. Note whether you are in the fire zone, the Hillside Area, both or neither. That one line tells you which ADU types are on the table before anyone draws plans.

Sorting out which map applies to a specific lot, and what it does to the design, is the kind of thing a lot check settles.

Quick answers

Does the fire zone stop a garage conversion?

No. Converting existing space is a state-law ADU type, and the city says the fire-zone and Hillside restriction may not be enforced on state-law ADUs 13.

Will I have to install fire sprinklers in my ADU?

Only if your main house was required to have them or already has a sprinkler system 717. Building the ADU does not force sprinklers into the main house 7.

How big can my ADU be in a fire zone that is also a Hillside Area?

A detached state-law ADU can be up to 800 square feet, and a JADU up to 500 square feet 24. The city's larger Ordinance ADU is restricted on lots in both zones 1.

Did the fire hazard maps change in 2025?

Yes. CAL FIRE issued new recommended maps for Los Angeles on March 24, 2025, and the Fire Department expects more parcels to be affected 9.

Sources

  1. ZA Memorandum No. 143, Revision 1 (LAMC Chapter 1): Implementation of the ADU Ordinance and State ADU Law, issued Aug. 1, 2025, Q.42, Los Angeles City Planning / LADBS. Facts checked 2026-10-08
  2. ZA Memorandum No. 143, Revision 1 (LAMC Chapter 1): Implementation of the ADU Ordinance and State ADU Law, issued Aug. 1, 2025, quoting Gov. Code § 66323(a)(2), Los Angeles City Planning / LADBS. Facts checked 2026-10-08
  3. ZA Memorandum No. 143, Revision 1 (LAMC Chapter 1): Implementation of the ADU Ordinance and State ADU Law, issued Aug. 1, 2025, on Gov. Code § 66323(a)(1), Los Angeles City Planning / LADBS. Facts checked 2026-10-08
  4. ZA Memorandum No. 143, Revision 1 (LAMC Chapter 1): Implementation of the ADU Ordinance and State ADU Law, issued Aug. 1, 2025, section B (JADUs), Los Angeles City Planning / LADBS. Facts checked 2026-10-08
  5. Accessory Dwelling Unit Plan Check Correction Sheet (PC/STR/Corr.Lst.20A1, Rev. 8/03/2021), item C.1, Los Angeles Department of Building and Safety (LADBS). Facts checked 2026-10-08
  6. Accessory Dwelling Unit Plan Check Correction Sheet (PC/STR/Corr.Lst.20A1, Rev. 8/03/2021), item B.7, Los Angeles Department of Building and Safety (LADBS). Facts checked 2026-10-08
  7. ZA Memorandum No. 143, Revision 1 (LAMC Chapter 1): Implementation of the ADU Ordinance and State ADU Law, issued Aug. 1, 2025, Q.31 (Gov. Code § 66314(d)(12)), Los Angeles City Planning / LADBS. Facts checked 2026-10-08
  8. Greenlight parcel count: LA County Assessor parcels (City of LA single-family, ZIP 91344) intersected with the City of LA Very High Fire Hazard Severity Zones layer, LA County Assessor parcel layer / City of Los Angeles GeoHub (Greenlight analysis). Facts checked 2026-10-08
  9. 2025 CAL FIRE Fire Hazard Severity Zones Map Recommendation (Apr. 4, 2025), Los Angeles Fire Department. Facts checked 2026-10-08
  10. Building and Safety - Building Permits Issued from 2020 to Present (N), dataset pi9x-tg5x (Greenlight query by Valley ZIP), City of Los Angeles Open Data / LADBS. Facts checked 2026-10-08
  11. ZA Memorandum No. 143, Revision 1 (LAMC Chapter 1): Implementation of the ADU Ordinance and State ADU Law, issued Aug. 1, 2025, section II, Los Angeles City Planning / LADBS. Facts checked 2026-10-08
  12. ZA Memorandum No. 143, Revision 1 (LAMC Chapter 1): Implementation of the ADU Ordinance and State ADU Law, issued Aug. 1, 2025, Table 1 (detached ADUs), Ordinance ADU column, Los Angeles City Planning / LADBS. Facts checked 2026-10-08
  13. ZA Memorandum No. 143, Revision 1 (LAMC Chapter 1): Implementation of the ADU Ordinance and State ADU Law, issued Aug. 1, 2025, Q.32, Los Angeles City Planning / LADBS. Facts checked 2026-10-08
  14. Los Angeles ADU ordinance review letter (findings), Nov. 19, 2024, California Department of Housing and Community Development (HCD). Facts checked 2026-10-08
  15. Zoning Code glossary: Hillside Area, Los Angeles City Planning. Facts checked 2026-10-08
  16. California Building Code Chapter 7A, Materials and Construction Methods for Exterior Wildfire Exposure, Section 701A.2 (2010 edition text), California Department of Housing and Community Development (HCD). Facts checked 2026-10-08
  17. Accessory Dwelling Unit Plan Check Correction Sheet (PC/STR/Corr.Lst.20A1, Rev. 8/03/2021), item E.4, Los Angeles Department of Building and Safety (LADBS). Facts checked 2026-10-08
  18. Zoning Code glossary: Very High Fire Hazard Severity Zone, Los Angeles City Planning. Facts checked 2026-10-08

Keep reading

Greenlight is not a contractor, architect or engineer, and this is not legal advice. Rules change; every fact here shows the date we last checked it.