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Building an ADU in Santa Monica: planning with local data

ADUs in Santa Monica: what local data means for your project

Santa Monica issued 143 ADU building permits in 2025 as reported so far, and 73.4% of housing units were built before 1980 (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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Santa Monica at a glance

ADU units with building permits issued in 2025 as reported so far, Santa Monica
143
ADU units completed in 2025 as reported so far, Santa Monica
6
Rank by ADU units permitted in 2025 among Los Angeles County cities that filed, Santa Monica
10 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 Santa Monica. 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.

Santa Monica housing and ADU permit facts

Santa Monica housing and ADU permit facts

Local numbers for Santa Monica, each with its source and date.

Change in ADU units permitted, 2022 to 2025, Santa Monica1
3.6%
Share of Santa Monica housing units built before 1980, 2020 to 20242
73.4%
Median year structure built, all Santa Monica housing units, 2020 to 20242
1968
Share of occupied Santa Monica housing units that are owner-occupied, 2020 to 20242
27.9%
Median value of owner-occupied Santa Monica homes, 2020 to 20242
$1,755,500
  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 Santa Monica, by yearEach bar is one year of building permits, as the city reported them to the state.

10th 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

What Santa Monica's homes mean for your ADU

Most homes in Santa Monica are older: 73.4% of housing units were built before 1980, and the median year built is 1968 (Census 2020–2024). That age shapes what an ADU needs. Plan for the existing house as well as the new unit.

Check the electrical panel first. An older main house may not have spare capacity for a new kitchen, bath and heating load. Water and sewer lines may also be shared with the main house, so ask how the new unit will connect and whether those lines need work. If you plan to convert an old garage, test for lead-based paint in structures built before 1978 and ask about possible asbestos in older materials. These are things to check, not certainties for every house.

Owners who rent out a property should plan for tenants too. Only 27.9% of occupied homes are owner-occupied, so renting is common here. Schedule noisy work around tenants and keep them informed about dates. The median value of owner-occupied homes is $1,755,500 (Census 2020–2024). Use that as context for how much to put into a home relative to its value, not as a resale forecast.

Permit activity is active, but the counts can change. 143 ADU units had permits issued in 2025 as reported so far, and 6 units were completed in 2025 as reported so far.

The typical path for an ADU in Santa Monica

The typical path for an ADU in Santa Monica

  1. Check what your lot allows

    Ask the city what your lot allows for an ADU, including setbacks, height and parking. Confirm the rules for your address before you spend money on design.

  2. Design and plans

    Your builder drafts the plans. For an older house, the plans should show the electrical panel, the water and sewer connections, and any garage conversion work in detail.

  3. Plan check and permit

    Submit the plans to the city for plan check and permit. Expect comments and corrections. Ask your builder to answer them in writing.

  4. Construction with inspections

    Build the unit with inspections at the stages the city requires. Before a garage conversion starts, have lead-based paint testing done for structures built before 1978 and ask about possible asbestos in older materials.

  5. Final sign-off

    Once the final inspections pass, the city signs off on the project. Keep the sign-off papers with your home records.

Questions about ADUs in Santa Monica

How many ADU permits does Santa Monica issue?

The state HCD report shows 143 ADU units with building permits issued in 2025, as reported so far. That count can still rise as late reports arrive. Among the 79 Los Angeles County cities that filed, Santa Monica ranks 10 of 79 for that year. Only 6 ADU units were completed in 2025, as reported so far.

Does building an ADU on an older Santa Monica lot add extra checks?

It can. 73.4% of Santa Monica housing units were built before 1980, and the median year built is 1968 (Census 2020–2024). Older houses may have a small electrical panel, shared water and sewer lines, and older materials. Have the builder check these before design starts.

What if I rent out my home in Santa Monica?

Only 27.9% of occupied Santa Monica homes are owner-occupied (Census 2020–2024), so renting is common here. If you plan to rent the ADU or the main house, talk through the schedule with your builder and keep your tenants informed about work dates. Check the local rules for your situation with the city.

How should I think about budget against home value?

The median value of owner-occupied Santa Monica homes is $1,755,500 (Census 2020–2024). Use that as context for how much to put into your home relative to its value. It is not a resale forecast. Ask your builder for a written estimate that lists the work in full.

How can I check a contractor before I hire one?

Check any contractor's license status with the CSLB (Contractors State License Board) before you sign anything. Ask the builder who receives your request to explain the scope, the schedule and how the work will be inspected.

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 Santa Monica 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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