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Can you build an ADU in Sherman Oaks?

On most Sherman Oaks house lots, yes, but the hills decide which kind. In 91403, 58 percent of single-family parcels are in the city's Very High Fire Hazard Severity Zone and 54 percent are in both that zone and a Hillside Area; in 91423 the shares are 35 and 34 percent 2. The city's own ADU rules restrict building on those lots, but City Planning says that restriction cannot be enforced on a State ADU, such as one detached unit of up to 800 sq ft with 4-foot side and rear setbacks 65.

Edited by Ryan Rambo, construction managerFacts checked 2026-10-12

How big are Sherman Oaks lots, and is there room for an ADU?

Usually there is room, and Sherman Oaks lots run larger than the flat Valley tracts. We counted every City of Los Angeles single-family parcel on the LA County Assessor's parcel map in the two Sherman Oaks ZIP codes 1:

An 800 sq ft backyard house covers less than 10 percent of an 8,555 sq ft lot. On a sloped lot, though, the usable flat ground decides where a unit fits, not the total area. The state does not let cities set a minimum lot size for ADUs 12.

There are two ways to size the unit. A State ADU is one detached new unit of up to 800 sq ft with 4-foot side and rear setbacks 5, and the city's floor-area limit (RFA) in the R1, RE, RS and RA zones cannot be enforced against it 8. Under the city's own rules an Ordinance ADU can reach 1,200 sq ft and two stories 9, but floor area, front yard and lot coverage limits can shrink it 8. On a lot in both the fire zone and a Hillside Area, the Ordinance ADU route is largely closed, as the next sections explain.

Is my Sherman Oaks lot in the fire zone or a Hillside Area?

In 91403 it is more likely than not. We tested each single-family parcel's center point against the city's GeoHub map layers for the Hillside Area and the Very High Fire Hazard Severity Zone (VHFHSZ) 2:

Treat these counts as a floor. The city's fire-zone layer was last edited in 2019 2. CAL FIRE issued new recommended fire hazard maps for the City of Los Angeles in March 2025, the Fire Department expects more parcels to be covered, and state law does not let the city lower the state's recommended zones 11. Look up your own parcel on ZIMAS, the City Planning map that shows a parcel's zoning and permit history 4.

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

Yes, through the state route. The city code, LAMC 12.22 A.33(c)(4), prohibits ADUs on a lot in both zones unless a few exceptions are met, but City Planning says that restriction may not be enforced on State ADUs 6. State ADUs are exempt from local zoning, design and development standards 7.

On a lot with one house, the state route covers:

The building still has to meet fire-zone construction rules. The LADBS ADU correction sheet requires the materials and construction methods of Chapter 7A for a building in the Very High Fire Hazard Severity Zone 10.

We cover the details in separate guides: building in a fire zone, the Hillside Ordinance, fire sprinklers, the 150-foot fire access rule, soils reports and height limits.

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 →

My house is near Mulholland Drive. Does the scenic parkway plan apply to an ADU?

It may, so ask City Planning before anyone designs. The Mulholland Scenic Parkway Specific Plan has an outer corridor that reaches up to one-half mile out from the Mulholland Drive right-of-way 13, and the plan defines a project as the construction of any building or structure on a lot that is wholly or partly in the plan area 14.

City Planning's handout for the plan says projects that add more than 900 sq ft, counted cumulatively since the plan was adopted in 1992, go to the Mulholland Design Review Board, while smaller projects may be approved through an Administrative Clearance 15. The same handout requires a tree disclosure statement when protected trees or shrubs are on the site 16.

City Planning's ADU memo also says State ADUs are exempt from local zoning, design and development standards 7. How the specific plan and the state rules fit together for your ADU is a question for City Planning, in writing. ZIMAS shows whether your parcel is in the plan area 4. If you have oaks or other native trees, read our protected trees guide.

Are other Sherman Oaks homeowners actually getting ADU permits?

Yes, but mostly on the flatter streets. Here are LADBS ADU and JADU building permits by year of issue 3:

Scaled to a full year, 91423 is running about 7 percent ahead of 2025, and 91403 is running more than a fifth behind 3.

The hills show up in the map of where permits land. More than half of the houses in 91403 are in a Hillside Area, but only 11 of its 76 ADU permits since January 2025 were on hillside parcels. In 91423 it was 11 of 143 32. Most permits were filed as alterations to an existing building rather than new buildings: 48 of 76 in 91403 and 87 of 143 in 91423 3.

These counts include ADUs on duplex and apartment lots, and they count permits, not homes. For how Sherman Oaks compares with the rest of the Valley, see our ZIP-by-ZIP permit count, and for neighbors over the hill, our Studio City and Encino guides.

What should I check first for my Sherman Oaks address?

Start with the free map lookups and work toward the expensive reports.

  1. ZIMAS: your zone, whether the parcel is in a Hillside Area, the Very High Fire Hazard Severity Zone or a specific plan, and the permit history of the house and garage 4.
  2. Which route you are on: if the lot is in both the fire zone and a Hillside Area, plan around a State ADU of up to 800 sq ft or a conversion of existing space 6518.
  3. Mulholland: if ZIMAS shows the Mulholland Scenic Parkway Specific Plan, ask City Planning which review applies before design starts 1315.
  4. The ground: slope, flat area, and how far the back of the lot is from the street for fire access. Our fire access and soils guides explain why these matter.
  5. Trees: protected oaks and native shrubs near where you want to build 16.

This is the kind of thing a lot check settles in one pass, before you pay for plans.

Quick answers

Is there a minimum lot size for an ADU in Sherman Oaks?

No. State law does not allow cities to set minimum lot size requirements for ADUs 12.

Can the city deny an ADU because my lot is in the fire zone and a Hillside Area?

Not a State ADU. City Planning says the city's ban on ADUs in both zones may not be enforced on State ADU types 6.

How tall can a detached ADU be in Sherman Oaks?

A detached State ADU has a base height limit of 16 feet, raised to 18 feet near a major transit stop or high-quality transit corridor 19.

How long does the city have to decide on my ADU application?

Once the application is complete, the city has 60 days to approve or deny it, or it is deemed approved 17.

Sources

  1. LA County Assessor parcel layer (LACounty_Parcel), City of Los Angeles single-family parcels in ZIPs 91403 and 91423, LA County Assessor (Greenlight analysis). Facts checked 2026-10-12
  2. City of LA GeoHub Special_Areas layers 6 (Hillside Ordinance) and 11 (Very High Fire Hazard Severity Zones), matched to single-family parcels in 91403 and 91423, City of Los Angeles GeoHub / LA County Assessor (Greenlight analysis). Facts checked 2026-10-12
  3. Building Permits Issued from 2020 to Present (N), dataset pi9x-tg5x, ZIPs 91403 and 91423, LADBS via City of Los Angeles Open Data (Greenlight query). Facts checked 2026-10-12
  4. Zoning Search (ZIMAS), Los Angeles City Planning. Facts checked 2026-10-12
  5. Accessory Dwelling Unit Handbook (March 2026), 66323 Units: Single-Family Detached ADUs, California Department of Housing and Community Development (HCD). Facts checked 2026-10-12
  6. ZA Memorandum No. 143, Revision 1 (LAMC Chapter 1): Implementation of the ADU Ordinance and State ADU Law, updated Aug. 1, 2025, Q.42, Los Angeles City Planning / LADBS. Facts checked 2026-10-12
  7. ZA Memorandum No. 143, Revision 1 (LAMC Chapter 1), updated Aug. 1, 2025, on GC § 66323(a), Los Angeles City Planning / LADBS. Facts checked 2026-10-12
  8. ZA Memorandum No. 143, Revision 1 (LAMC Chapter 1), updated Aug. 1, 2025, Q.3, Los Angeles City Planning / LADBS. Facts checked 2026-10-12
  9. ZA Memorandum No. 143, Revision 1 (LAMC Chapter 1), updated Aug. 1, 2025, Table 1 (detached ADUs), Ordinance ADU column, Los Angeles City Planning / LADBS. Facts checked 2026-10-12
  10. Accessory Dwelling Unit Plan Check Correction Sheet, item C.1, Los Angeles Department of Building and Safety (LADBS). Facts checked 2026-10-12
  11. 2025 CAL FIRE Fire Hazard Severity Zones Map Recommendation (Apr. 4, 2025), Los Angeles Fire Department. Facts checked 2026-10-12
  12. Accessory Dwelling Unit Handbook (March 2026), Lot size, California Department of Housing and Community Development (HCD). Facts checked 2026-10-12
  13. Mulholland Scenic Parkway Specific Plan (Ordinance No. 167,943), Section 4 definitions: Outer Corridor, Los Angeles City Planning. Facts checked 2026-10-12
  14. Mulholland Scenic Parkway Specific Plan (Ordinance No. 167,943), Section 4 definitions: Project, Los Angeles City Planning. Facts checked 2026-10-12
  15. Mulholland Scenic Parkway Specific Plan General Information Handout (CP13-3618, Jan. 20, 2026), Thresholds of Review, Los Angeles City Planning. Facts checked 2026-10-12
  16. Mulholland Scenic Parkway Specific Plan General Information Handout (CP13-3618, Jan. 20, 2026), Trees or Shrubs, Los Angeles City Planning. Facts checked 2026-10-12
  17. Accessory Dwelling Unit Handbook (March 2026), Summary of Recent Changes, California Department of Housing and Community Development (HCD). Facts checked 2026-10-12
  18. ZA Memorandum No. 143, Revision 1 (LAMC Chapter 1), updated Aug. 1, 2025, on GC § 66323(a)(1), Los Angeles City Planning / LADBS. Facts checked 2026-10-12
  19. Accessory Dwelling Unit Handbook (March 2026), Summary of Recent Changes: Detached ADU Height Allowances, California Department of Housing and Community Development (HCD). Facts checked 2026-10-12

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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.