Can you build an ADU in Van Nuys?

How big are Van Nuys lots, and is there room for an ADU?

There is usually room. We counted every City of Los Angeles single-family parcel on the LA County Assessor's parcel map in the three Van Nuys ZIP codes ¹:

• 91405 (Van Nuys): 3,778 parcels, median lot 6,866 sq ft, half of all lots between 6,299 and 7,816 sq ft
• 91406 (Van Nuys / Lake Balboa): 7,487 parcels, median 6,592 sq ft, half between 6,014 and 7,805 sq ft
• 91411 (Van Nuys): 2,150 parcels, median 6,752 sq ft, half between 6,402 and 7,158 sq ft

An 800 sq ft backyard house takes up about 12 percent of a 6,600 sq ft lot. The state does not let cities set a minimum lot size for ADUs ²¹. The house, the driveway and the setbacks decide where a unit fits.

The same Assessor records show how old these houses are. The median single-family house in all three ZIPs was built around 1950, and 86 percent of houses in 91405, 90 percent in 91406 and 95 percent in 91411 were built before 1960 ¹.

In our earlier count, no single-family parcel in 91405 or 91406 touched the city's Very High Fire Hazard Severity Zone map layer, which was last edited in 2019 ¹. Confirm your own parcel on ZIMAS.

What can I build on a regular Van Nuys house lot?

Most owners choose between a new backyard house, a garage conversion and a JADU. Start by looking up your address on ZIMAS, the City Planning map that shows a parcel's zoning and its building permit history ³.

• State ADU. One detached new unit of up to 800 sq ft with 4-foot side and rear setbacks is allowed on a lot with a single-family house ⁴. The city's floor-area limit (RFA) in the R1, RE, RS and RA zones cannot be enforced against a State ADU ⁵.
• Ordinance ADU. Under the city's own rules a detached unit can reach 1,200 sq ft and two stories ⁶, but other zoning limits such as floor area, front yard setbacks and lot coverage can shrink it ⁵.
• Garage conversion. State law allows a detached garage to be converted to an ADU ⁷, and no setback is required when the unit stays inside an existing structure or is rebuilt in the same spot to the same size ⁸.
• JADU. A junior unit of no more than 500 sq ft inside the house ²³.

We cover the details elsewhere: setbacks, height limits, JADU versus ADU and checking whether your garage was permitted. Our guide to garage conversions in Reseda walks through a similar Valley tract lot.

My Van Nuys lot already has a duplex or apartments. Can I still add an ADU?

Yes, and the rules are different from a single-family lot. Van Nuys has a lot of these properties: the Assessor lists 210 parcels in 91405, 239 in 91406 and 198 in 91411 as two-, three- or four-unit properties, plus 509, 396 and 392 parcels with five or more apartments ¹.

State law gives multifamily lots two tracks, and they can be combined ¹¹:

1. Conversions. ADUs can be built in parts of an existing multifamily building that are not living space, such as storage rooms, boiler rooms, attics, basements or garages. The city must allow at least one, and up to 25 percent of the existing unit count ¹⁰.
2. Detached units. On a lot with an existing multifamily building, up to eight detached ADUs are allowed, but never more than the number of existing units. They get 4-foot side and rear setbacks and the same 16, 18 or 20 foot height limits ¹¹.

One detail matters on older Van Nuys lots. For state ADU law, a multifamily dwelling means two or more units attached in one structure. Two separate houses on one lot do not count as a multifamily dwelling ⁹. If your property is a front house and a back house, ask the city which track applies before you design.

If the existing building is a rental, also read our guide on ADUs and rent control (RSO).

Does Van Nuys Airport limit what I can build?

Rarely for an ADU, but you should know the rule exists. The city's airport approach zoning, LAMC Section 12.50, sets height limits and land-use rules in the airport hazard areas around Van Nuys Airport and LAX ¹². Its own exception says it does not stop structures up to 45 feet above natural or finished grade, whichever is lower ¹³.

A State ADU tops out at 16, 18 or 20 feet ⁴, far under that line. If ZIMAS shows an airport hazard note on your parcel, read it, but height is unlikely to be the problem.

Are other Van Nuys homeowners actually getting ADU permits?

Yes, steadily, and 91406 is one of the busiest ZIPs in the Valley. Here are LADBS ADU and JADU building permits by year of issue ²:

• 91406 (Van Nuys / Lake Balboa): 126 in 2023, 135 in 2024, 163 in 2025, and 101 from January 1 through October 3, 2026
• 91405 (Van Nuys): 56, 85, 77, and 60 so far in 2026
• 91411 (Van Nuys): 42, 29, 32, and 38 so far in 2026

Scaled to a full year, 91406 is running about 18 percent below its 2025 record, 91405 is about level, and 91411 is about 56 percent ahead, though small counts swing easily ². Of the 264 permits in 91406 since January 2025, 126 were filed as alterations to an existing building, 79 as new buildings and 59 as additions ². Only 13 of the 471 permits across all three ZIPs since 2025 were for JADUs ².

These counts include ADUs on duplex and apartment lots, and they count permits, not homes: one project can carry more than one permit. For how Van Nuys compares with the rest of the Valley, see our ZIP-by-ZIP permit count.

What utility problems should I check on an older Van Nuys lot?

On houses built around 1950, check the old sewer line and electrical service before anyone draws plans.

1. Sewer. Find the public sewer main near your house on NavigateLA, the city map Bureau of Engineering staff use to confirm a public sewer is available ¹⁴. Your lateral has an upper part from your building to the property line and a lower part from the property line to the middle of the street ¹⁵. Our sewer guide covers what happens when the main is far away.
2. Separate water and power. A unit made from existing space, such as a garage conversion, cannot be required to get a new or separate utility connection; a new detached unit can be ¹⁶. A unit built from existing space is also not treated as a new residential use for connection fees, unless it is built along with a new house ¹⁷. See our guides on the LADWP water meter and the electrical panel.
3. Easements. Any work within 10 feet of an LADWP easement, including a garage conversion, needs written LADWP approval ¹⁸. Our easements guide explains how to find one.
4. Sign-offs from other departments. LADBS warns that some departments can take months to clear a project, so start early ¹⁹.

What should I check first, and in what order?

Go from the free answers to the expensive ones.

1. ZIMAS: your zone, any airport hazard or other overlay, and the permit history of the house and garage ³.
2. What is on the lot now: one house, a front and back house, or an attached duplex or apartment building, since each follows different ADU rules ⁹¹¹.
3. Lot history: LADBS checks when the lot was created, and lots divided after certain dates must meet zone rules or get a Certificate of Compliance ²⁰.
4. Sewer: where the main is and the condition of your lateral ¹⁴¹⁵.
5. Power, water and easements: your panel rating, whether you want separate meters, and any LADWP easement within 10 feet of where you want to build ¹⁶¹⁸.

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

Quick answers

Sources

1. LA County Assessor parcel layer (LACounty_Parcel), City of Los Angeles parcels in ZIPs 91405, 91406 and 91411; with LA City GeoHub Very High Fire Hazard Severity Zones layer, LA County Assessor / City of Los Angeles GeoHub (Greenlight analysis). Facts checked 2026-10-11
2. Building Permits Issued from 2020 to Present (N), dataset pi9x-tg5x, ZIPs 91405, 91406, 91411, LADBS via City of Los Angeles Open Data (Greenlight query). Facts checked 2026-10-11
3. Zoning Search (ZIMAS), Los Angeles City Planning. Facts checked 2026-10-11
4. Accessory Dwelling Unit Handbook (March 2026), 66323 Units: Single-Family Detached ADUs, California Department of Housing and Community Development (HCD). Facts checked 2026-10-11
5. ZA Memo No. 143 Revision 1, Accessory Dwelling Units (August 2025), Los Angeles City Planning, Office of Zoning Administration. Facts checked 2026-10-11
6. ZA Memo No. 143 Revision 1, ADU types summary table (Ordinance ADU vs State ADU), Los Angeles City Planning, Office of Zoning Administration. Facts checked 2026-10-11
7. Accessory Dwelling Unit Handbook (March 2026), Detached ADUs, California Department of Housing and Community Development (HCD). Facts checked 2026-10-11
8. Accessory Dwelling Unit Handbook (March 2026), Setbacks, California Department of Housing and Community Development (HCD). Facts checked 2026-10-11
9. Accessory Dwelling Unit Handbook (March 2026), Definitions: Multifamily Dwelling, California Department of Housing and Community Development (HCD). Facts checked 2026-10-11
10. Accessory Dwelling Unit Handbook (March 2026), Multifamily Converted ADUs, California Department of Housing and Community Development (HCD). Facts checked 2026-10-11
11. Accessory Dwelling Unit Handbook (March 2026), Multifamily Detached ADUs, California Department of Housing and Community Development (HCD). Facts checked 2026-10-11
12. LAMC Sec. 12.50 Airport Approach Zoning Regulations, Subsection A (text as of 2026-10-05), Los Angeles Municipal Code, reproduced by GoCodebook. Facts checked 2026-10-11
13. LAMC Sec. 12.50 Airport Approach Zoning Regulations, Subsection H. Exception, Los Angeles Municipal Code, reproduced by GoCodebook. Facts checked 2026-10-11
14. Sewer (S) Permits: S-Permit Processing Procedures, City of Los Angeles Bureau of Engineering (BOE) Permit Manual. Facts checked 2026-10-11
15. Managing and Protecting LA's Underground Sewer System, LA Sanitation and Environment. Facts checked 2026-10-11
16. Accessory Dwelling Unit Handbook (March 2026), Utilities: new or separate connections, California Department of Housing and Community Development (HCD). Facts checked 2026-10-11
17. Accessory Dwelling Unit Handbook (March 2026), Fees, California Department of Housing and Community Development (HCD). Facts checked 2026-10-11
18. Accessory Dwelling Unit Plan Check Correction Sheet, item B.8, Los Angeles Department of Building and Safety (LADBS). Facts checked 2026-10-11
19. Accessory Dwelling Unit Plan Check Correction Sheet, item B.1, Los Angeles Department of Building and Safety (LADBS). Facts checked 2026-10-11
20. Accessory Dwelling Unit Plan Check Correction Sheet, item B.2, Los Angeles Department of Building and Safety (LADBS). Facts checked 2026-10-11
21. Accessory Dwelling Unit Handbook (March 2026), Lot size, California Department of Housing and Community Development (HCD). Facts checked 2026-10-11
22. Accessory Dwelling Unit Handbook (March 2026), Summary of Recent Changes, California Department of Housing and Community Development (HCD). Facts checked 2026-10-11
23. Accessory Dwelling Unit Handbook (March 2026), What is a JADU?, California Department of Housing and Community Development (HCD). Facts checked 2026-10-11

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.