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Building an ADU in Santa Clara, CA

Checked against the city's ADU pages on Oct 18, 2026.

Can I build one?
Yes, up to 1,200 sq ft Detached ADUs can be 1,200 sq ft on lots over 5,500 sq ft, or 1,000 sq ft on smaller lots. No parking required.[1]
What will the city charge?
8 fee lines The city doesn't publish a total for an ADU, so we list each charge. See every fee[2]
Who builds here?
13 licensed builders Each lists Santa Clara on its own site and holds an active CSLB license. See the list
See 13 builders Get quotes

Licensed ADU builders in Santa Clara

Ranked by a public score anyone can check: license, years licensed, ADU types and cities shown on their own sites, a local office, and published prices. Nobody pays to move up. Quote requests go to our team with the builder you picked. How we rank

What Santa Clara allows

  • Detached ADU, max size[1]

    1,000 sq ft on lots up to 5,500 sq ft; 1,200 sq ft on larger lots

  • Attached ADU, max size[1]

    1,000 sq ft or 50% of the main home, whichever is less; 800 sq ft is always allowed

  • Conversion of existing space[1]

    No size cap; up to 150 sq ft can be added for an entry

  • Junior ADU (inside the house)[1]

    Up to 500 sq ft, inside the walls of the house; not allowed in an accessory building

  • Height[1]

    Detached: 18 ft one story, 25 ft for 1.5 stories. Attached: up to 25 ft and 2 stories, matching the house

  • Side and rear setbacks[1]

    Detached: 4 ft side, rear and corner side; 6 ft from the main home; 15 ft rear for parts over one story

  • Units on a single-family lot[1]

    1 detached ADU + 1 JADU + 1 converted ADU, or one ADU or JADU on its own

  • Parking[1]

    None. A garage or carport you convert or tear down doesn't need replacing

  • Owner must live on site[1]

    No for an ADU. For a JADU, only if it shares a bathroom with the house

  • Permit path[3]

    Building permit only, except a new attached second-story ADU on a one-story house, which needs Architectural Review
  • Minimum size is 150 sq ft. There is no minimum lot size.[1]
  • An ADU can't sit in an easement or in the sight-distance triangle at a driveway or intersection.[1]
  • On a property listed in the California Register of Historical Resources, an ADU needs a Significant Property Alteration permit.[1]
  • A JADU can't be rented for less than 30 days and needs a recorded deed restriction.[1]
ADU rules in Santa Clara drawn on a typical lot Detached ADU: up to 1,200 square feet, 4 feet from side and rear lot lines, 18 feet tall. Parking: None required. Rear lot line Street Main house ADU up to 1,200 sq ft 18 ft tall 4 ft 4 ft 6 ft apart Parking: none required
Detached ADU. Not to scale.

City fees for an ADU in Santa Clara

Fee lines for an ADU in Santa Clara
Building plan review, scaled by size $732 for the first 250 sq ft, plus $292.80 per 100 sq ft up to 1,000 sq ft; $2,928 at 1,000 sq ft, plus $146.40 per 100 sq ft above that[2] A 3.37% technology fee is added.
Building permit fee, scaled by size $812 for the first 250 sq ft, plus $249.50 per 100 sq ft up to 1,000 sq ft; $2,684 at 1,000 sq ft, plus $211.40 per 100 sq ft above that[2] A 3.37% technology fee is added.
Architectural Review for an ADU or JADU $306[2][3] Only if your ADU doesn't qualify for the building-permit-only path.
Park fee $0 under 750 sq ft[2][4] The fee schedule has no ADU park line. State law bars impact fees under 750 sq ft; larger ADUs pay in proportion to the main home.
School fees Santa Clara Unified: $5.38 per sq ft; $0 under 500 sq ft[5]
Sewer conveyance fee (City of Santa Clara) $1.14 per sq ft for ADUs 750 sq ft and larger; $0 under 750 sq ft[2]
Wastewater treatment plant capacity fee (City of Santa Clara) $747 per ADU[2]
Water service (City of Santa Clara) No ADU line; a new 1-inch meter is $239 for the device[2] Only if you add a meter. Ask Water & Sewer Utilities what your ADU needs.
School fee rates for districts in Santa Clara (1)

Santa Clara Unified is the district on record. The city publishes no school district map, so confirm your parcel's district before you budget.[5]

  • Santa Clara Unified School District[5]No fees on ADUs or additions under 500 sq ft. $5.38/sq ft
Total cost in Santa Clara, fees plus building

How the permit works

  1. 1

    Check your lot against the ADU handout

    The Rev. 01/26 handout lists sizes, heights and setbacks. Call Planning at 408-615-2450 with questions.[1]

  2. 2

    Prepare plans

    Hire a designer, or buy a pre-approved plan and add a site-specific plan set.[6]

  3. 3

    Apply for a building permit online

    Upload everything to the Permitting Online Portal (POP). Most ADUs need only a building permit.[7][3]

  4. 4

    Pay fees and get the permit

    Remaining fees, including building permit fees, are due before the permit is issued.[7]

  5. 5

    Build and pass inspections

    A permit stays valid 365 days from issuance or from the last passed inspection.[7]

Review time: With a complete pre-approved plan package, plan review takes about 10 business days after you pay, and 5 for later rounds.[6]

State deadline: State law gives the city 15 business days to say if your application is complete and 60 days to approve or deny a complete one.[4]

Apply at: Permitting Online Portal (POP)

Preapproved plans

Santa Clara has a pre-approved ADU plans program. Plan review takes about 10 business days if your site package is complete.[6]

Who qualifies: Residential lot with an existing house or duplex, not in a flood zone, not a historic property. Changes beyond minor ones end the fast review.

  • Basically Homes (VitalizeBuild Construction) 499 sq ft 1 bed / 1 bath, site-built, detached
  • Framework First 660 sq ft 2 bed / 1 bath, prefab, detached
  • Abodu Abodu Studio 340 sq ft; Abodu Two+ 800 sq ft 2 bed (State-approved)
  • ADORE Homes ADORE Horizon 933 sq ft 3+ bed (State-approved)

The city publishes no prices for these plans.

Common questions

How big can an ADU be in Santa Clara?

A detached ADU can be 1,000 sq ft on lots up to 5,500 sq ft and 1,200 sq ft on larger lots. An attached ADU is capped at 1,000 sq ft or half the main home, but 800 sq ft is always allowed. A junior ADU is up to 500 sq ft.[1]

What are the Santa Clara ADU requirements?

A detached ADU needs 4 ft side and rear setbacks and 6 ft from the main home. It can be 18 ft tall for one story or 25 ft for 1.5 stories. Most ADUs need only a building permit.[1][3]

Do I need parking for an ADU in Santa Clara?

No. Santa Clara requires no parking for an ADU or JADU, and you don't have to replace a garage you convert.[1]

How much is the ADU permit cost in Santa Clara?

The city publishes no total. Plan review and permit fees are scaled by size, starting at $732 and $812 for the first 250 sq ft. ADUs under 750 sq ft pay no sewer conveyance fee, and ADUs under 500 sq ft pay no Santa Clara Unified school fee.[2][5]

Do I have to live on the property?

Not for an ADU. For a junior ADU, the owner must live on site only if the JADU shares a bathroom with the house.[1]

Nearby cities

What we couldn't confirm

  • The city's old ADU web page now returns Page Not Found; rules come from the Rev. 01/26 handout.
  • No city-published fee total or fee estimator for ADUs.
  • Park fees for ADUs 750 sq ft and larger are not listed in the fee schedule.
  • School district lines within the city are not published; only Santa Clara Unified is recorded.
  • No published review time for a standard (not pre-approved) ADU permit.
  • Silicon Valley Power (electric) fees for an ADU not recorded.

Sources

Every fact on this page links to one of these. We read each one on the date shown.

  1. 1. City of Santa Clara Planning Division ADU and JADU Handout Rev Checked Oct 18, 2026
  2. 2. City of Santa Clara FY 2026/27 Municipal Fee Schedule, adopted April 21, 2026 (Res Checked Oct 18, 2026
  3. 3. City of Santa Clara Planning Division ADU section: ADU/JADU projects can be submitted as a Building Permit, except new attached second-story ADUs on Checked Oct 18, 2026
  4. 4. California Department of Housing and Community Development (HCD) All state ADU/JADU rules used in state_baseline.md (sizes, heights, setbacks, parking, owner-occupancy, JADU, Checked Oct 18, 2026
  5. 5. Santa Clara Unified School District Residential $5.38/sf effective 8/24/2026 Checked Oct 18, 2026
  6. 6. City of Santa Clara Building Division Pre-Approved ADU Plans program: lot zoned residential with an existing house or duplex, not in a flood zone, n Checked Oct 18, 2026
  7. 7. City of Santa Clara Building Division All applications submitted electronically through the Permitting Online Portal (POP) Checked Oct 18, 2026