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Building an ADU in Hawthorne, CA

ADUs in Hawthorne for older homes

76 ADU units had building permits issued in Hawthorne in 2025 as reported so far, and 67.5% of housing units were built before 1980 (Census 2020–2024).

Updated Sources: California HCD

Concept of a detached backyard ADU with white stucco, cedar siding and a small garden patio
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Hawthorne at a glance

ADU units with building permits issued in 2025 as reported so far, City of Hawthorne
76
ADU units completed in 2025 as reported so far, City of Hawthorne
53
Rank by ADU units permitted in 2025 among 79 reporting Los Angeles County cities, City of Hawthorne
23 of 79

California HCD, Housing Element Annual Progress Report (APR), Table A2 · data as of

  • Numbers from HCD and US Census public records
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What do permits say an ADU costs?

From City of LA building permits, last 12 months. Not a contract price. How we calculate this

Declared values on City of Los Angeles building permits, last 12 months. The dataset covers the City of Los Angeles only, so treat it as a regional reference for Hawthorne. A declared value is what the permit states, not your contract price. How we calculate this.

$140,544median declared value, new ADU

Middle half of 2,004 permits Median

Every lot is different. A local contractor can price your project.

Source: LA Department of Building and Safety, Building Permits Issued 2020 to Present (data.lacity.org), permits on one- and two-family homes issued to ; fire rebuilds excluded. ZIP medians need 20+ permits.

Hawthorne ADU permits and housing facts

Hawthorne ADU permits and housing facts

Local numbers for Hawthorne, each with its source and date.

Change in ADU units permitted, 2022 to 2025, City of Hawthorne1
204%
Share of housing units built before 1980, City of Hawthorne2
67.5%
Median year structure built, all housing units, City of Hawthorne2
1970
Share of occupied housing units that are owner-occupied, City of Hawthorne2
27.2%
Median value of owner-occupied homes, City of Hawthorne2
$863,400
  1. 1 California HCD, Housing Element Annual Progress Report (APR), Table A2 · data as of
  2. 2 U.S. Census Bureau, American Community Survey 2020–2024 5-year estimates · data as of
ADU units permitted in Hawthorne, by yearEach bar is one year of building permits, as the city reported them to the state.

23rd of 79 LA County cities for ADU permits in 2025

* 2025 counts can still rise as late reports come in. Source: California HCD, Housing Element Annual Progress Report (APR), Table A2, data as of .

Planning your project

Hawthorne's homes are mostly older. 67.5% of housing units were built before 1980 (Census 2020–2024), and the median year built is 1970. Before you plan an ADU, check how an older house and lot will fit the work.

What Hawthorne's homes mean for your ADU

An older main house may have an electrical panel with limited spare capacity. Water and sewer lines may also be shared with the main house. Ask your builder to check both early, because these can change the design and the scope of work.

If you convert an old garage, test for lead-based paint, which is a concern in structures built before 1978. Old materials can also contain asbestos. These are things to check, not certainties for every house.

Only 27.2% of occupied housing units are owner-occupied, so many properties here are rentals. If you rent out your home or plan to rent the ADU, plan how you will keep tenants informed and schedule the work around them.

The median value of owner-occupied homes is $863,400 (Census 2020–2024). Use that figure to think about how much to put into your home relative to its value. The city issued 76 ADU permits in 2025 as reported so far, and that count may still rise, so do not read it as a final trend.

How an ADU project usually goes in Hawthorne

How an ADU project usually goes in Hawthorne

  1. Check what your lot allows

    Ask the City of Hawthorne what your lot allows, including setbacks, height, and parking. Ask about the older-home items too: the electrical panel, shared water and sewer lines, and any garage conversion.

  2. Design and plans

    Your builder turns your goals into plans. For an older home, the plans should show the panel work, the utility connections, and any lead or asbestos testing needed for old materials.

  3. Plan check and permit

    The plans go to the city for review and a permit. Ask the builder who handles questions from the city and how long the review usually takes in your case.

  4. Construction and inspections

    Construction follows the approved plans. Inspections happen at set stages, such as framing, electrical, and plumbing. If you rent out your home, schedule noisy work around your tenants.

  5. Final sign-off

    After the final inspection, the city signs off on the finished unit. Keep your permit records and final sign-off papers with your property documents.

Questions about building an ADU in Hawthorne

How active is ADU permitting in Hawthorne?

State-reported data show 76 ADU units with building permits issued in 2025 as reported so far, ranked 23 of 79 Los Angeles County cities. That shows active ADU work in the city. It does not tell you how your own lot will be treated, so check the lot rules with the city before you commit to a design.

What should I check if my Hawthorne home is older?

Most homes here are older. The Census shows 67.5% of housing units were built before 1980, and the median year built is 1970. Ask your builder to check the electrical panel, the shared water and sewer lines, and, if you convert an old garage, lead paint and possible asbestos. These are things to check, not problems every house has.

Does the rental share matter for my ADU?

Only 27.2% of occupied housing units are owner-occupied, so many homes here are rentals. If you plan to rent the ADU or already rent out your property, plan how you will keep tenants informed and schedule noisy work around them. Ask your builder to help you set that schedule early.

How should the median home value affect my budget?

The median value of owner-occupied homes is $863,400 (Census 2020–2024). Use that figure only as a general guide: think about how much you put into your home relative to what it is worth, and set a budget that fits your plans. Your builder can give you a estimate based on your own project.

Who handles the city permit?

A local builder can help with plans and submit them to the City of Hawthorne for plan check and permit. Ask who handles each step and what the city will need from you. You can check any contractor's license status with the CSLB (Contractors State License Board).

Compare ADU activity across LA County

Where LA County is building ADUs

ADU units permitted in 2025, city by city. Select a city to open its guide.

Map of LA County cities shaded by ADU units permitted in 2025, with Hawthorne outlinedAgoura Hills: 17 ADU units permitted in 2025Alhambra: 102 ADU units permitted in 2025Arcadia: 98 ADU units permitted in 2025Artesia: 39 ADU units permitted in 2025Azusa: no HCD reportBaldwin Park: 119 ADU units permitted in 2025Bell: 25 ADU units permitted in 2025Bell Gardens: 26 ADU units permitted in 2025Bellflower: 18 ADU units permitted in 2025Beverly Hills: 31 ADU units permitted in 2025Bradbury: no HCD reportBurbank: 241 ADU units permitted in 2025Calabasas: 15 ADU units permitted in 2025Carson: 41 ADU units permitted in 2025Cerritos: 12 ADU units permitted in 2025Claremont: 23 ADU units permitted in 2025Commerce: no HCD reportCompton: no HCD reportCovina: 34 ADU units permitted in 2025Cudahy: 24 ADU units permitted in 2025Culver City: 83 ADU units permitted in 2025Diamond Bar: 50 ADU units permitted in 2025Downey: 146 ADU units permitted in 2025Duarte: 23 ADU units permitted in 2025El Monte: 107 ADU units permitted in 2025El Segundo: 25 ADU units permitted in 2025Gardena: 52 ADU units permitted in 2025Glendale: 371 ADU units permitted in 2025Glendora: 57 ADU units permitted in 2025Hawaiian Gardens: 11 ADU units permitted in 2025Hawthorne: 76 ADU units permitted in 2025Hermosa Beach: 11 ADU units permitted in 2025Hidden Hills: no HCD reportHuntington Park: 45 ADU units permitted in 2025Industry: no HCD reportInglewood: 147 ADU units permitted in 2025Irwindale: no HCD reportLa Canada Flintridge: 30 ADU units permitted in 2025La Habra Heights: no HCD reportLa Mirada: 23 ADU units permitted in 2025La Puente: 28 ADU units permitted in 2025La Verne: 22 ADU units permitted in 2025Lakewood: 99 ADU units permitted in 2025Lancaster: 209 ADU units permitted in 2025Lawndale: no HCD reportLomita: 7 ADU units permitted in 2025Long Beach: 644 ADU units permitted in 2025Los Angeles: 7,446 ADU units permitted in 2025Lynwood: no HCD reportMalibu: 5 ADU units permitted in 2025Manhattan Beach: 24 ADU units permitted in 2025Maywood: no HCD reportMonrovia: 58 ADU units permitted in 2025Montebello: 61 ADU units permitted in 2025Monterey Park: 78 ADU units permitted in 2025Norwalk: 119 ADU units permitted in 2025Palmdale: 68 ADU units permitted in 2025Palos Verdes Estates: 20 ADU units permitted in 2025Paramount: 57 ADU units permitted in 2025Pasadena: 222 ADU units permitted in 2025Pico Rivera: 96 ADU units permitted in 2025Pomona: no HCD reportRancho Palos Verdes: 16 ADU units permitted in 2025Redondo Beach: 25 ADU units permitted in 2025Rolling Hills: no HCD reportRolling Hills Estates: 5 ADU units permitted in 2025Rosemead: 136 ADU units permitted in 2025San Dimas: 30 ADU units permitted in 2025San Fernando: 40 ADU units permitted in 2025San Gabriel: 54 ADU units permitted in 2025San Marino: 14 ADU units permitted in 2025Santa Clarita: 29 ADU units permitted in 2025Santa Fe Springs: 15 ADU units permitted in 2025Santa Monica: 143 ADU units permitted in 2025Sierra Madre: 26 ADU units permitted in 2025Signal Hill: 8 ADU units permitted in 2025South El Monte: 22 ADU units permitted in 2025South Gate: 154 ADU units permitted in 2025South Pasadena: 26 ADU units permitted in 2025Temple City: 69 ADU units permitted in 2025Torrance: 89 ADU units permitted in 2025Vernon: no HCD reportWalnut: 36 ADU units permitted in 2025West Covina: no HCD reportWest Hollywood: 36 ADU units permitted in 2025Westlake Village: no HCD reportWhittier: 86 ADU units permitted in 2025
ADU units permitted, 2025
  • 0–21
  • 22–28
  • 29–56
  • 57–99
  • 100+
  • No report
  • Unincorporated

Most ADU permits in 2025

  1. 1Los Angeles7,446
  2. 2Long Beach644
  3. 3Glendale371
  4. 4Burbank241
  5. 5Pasadena222
  6. 6Lancaster209
  7. 7South Gate154
  8. 8Inglewood147
  9. 9Downey146
  10. 10Santa Monica143

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Permits: California HCD, Housing Element Annual Progress Report (APR), Table A2, data as of ; 2025 counts can still rise. Boundaries: Los Angeles County, City and Unincorporated Boundaries (Legal) (mainland only (islands omitted). simplified to about 300 m.)

Recent work by a contractor in our network

Photos from the contractor's own projects, used with permission. Captions name the type of work.

  • Dark-tiled bathroom with a floating vanity and frameless glass
    Bathroom in an ADU
  • Living area in a new unit with a sofa and dining table
    Addition / ADU interior
  • Living room of a new unit with neutral furniture
    Addition / ADU interior
  • Bathroom vanity with a backlit mirror in a new unit
    Addition / ADU bathroom

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  • Dark-tiled bathroom with a floating vanity and frameless glass
  • Living area in a new unit with a sofa and dining table
  • Living room of a new unit with neutral furniture

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Service areas as listed by the contractor ()

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