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Building an ADU in Los Gatos, CA

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

Can I build one?
Yes, up to 1,200 sq ft ADUs can be 1,200 sq ft. Most ground-floor ADUs are capped at 16 ft and need 1 parking space unless an exception applies.[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?
12 licensed builders Each lists Los Gatos on its own site and holds an active CSLB license. See the list
See 12 builders Get quotes

The Town is rewriting its ADU rules. The Town Council was due to review a draft on August 4, 2026, and the outcome isn't posted yet. These are the rules from the Town's 2024 brochure.[3][1] Compare them

Licensed ADU builders in Los Gatos

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 Los Gatos allows

  • Detached ADU, max size[1]

    1,200 sq ft

  • Attached ADU, max size[1]

    1,200 sq ft

  • Junior ADU (inside the house)[1]

    Up to 500 sq ft, inside the house or attached garage; one per lot

  • Height[1]

    16 ft for most ground-floor ADUs; 25 ft for an ADU added to the second story of a two-story home

  • Side and rear setbacks[1]

    4 ft side and rear; front per the zone; 5 ft from other buildings

  • Floor area and lot coverage[1]

    ADUs don't count toward lot coverage. Up to 800 sq ft is exempt from floor area, and the Town adds a 10% floor area bonus for ADUs

  • Units on a single-family lot[1]

    1 ADU + 1 JADU

  • Parking[1]

    1 space per ADU, which can be tandem or in the driveway; exceptions in Town Code 29.10.320(f)(1). None for a JADU. A converted garage doesn't need replacing

  • Owner must live on site[1]

    No for an ADU; yes if there is a JADU
  • ADUs are one story. In some zones one can sit above an existing one-story accessory building when the main home is two stories.[1]
  • A draft 2026 ADU ordinance is posted by the Town and may change these rules.[3][4]
ADU rules in Los Gatos drawn on a typical lot Detached ADU: up to 1,200 square feet, 4 feet from side and rear lot lines, 16 feet tall. Parking: 1 space, with exceptions. Rear lot line Street Main house ADU up to 1,200 sq ft 16 ft tall 4 ft 4 ft 5 ft apart Parking: 1 space, with exceptions
Detached ADU. Not to scale.

City fees for an ADU in Los Gatos

Fee lines for an ADU in Los Gatos
Building permit, by valuation $1,749 for the first $100,000, plus $9.84 per $1,000 up to $500,000[2] Valuation is the ICC table × 2.32 (× 3.246 on hillside lots). FY 2026-27 schedule, effective July 1, 2026.
Plan review and surcharges Plan review 65% and Title 24 surcharge 15% of the building fee; $68 issuance; electrical, mechanical and plumbing $0.12 per sq ft each[2]
Planning add-ons Planning plan check 20% of the building fee; General Plan surcharge 0.5% of valuation; 4% permit tracking[5]
Traffic impact fee $0 under 750 sq ft; $1,128 per daily trip at 750 sq ft and up, scaled to the main home[1][2] The Town does not publish the trip rate it uses for an ADU.
Construction taxes $0.18 capital improvement + $0.18 underground utility + $0.04 park fund, per sq ft of added floor area[2] The schedule doesn't say whether these apply to a detached ADU.
School fees Los Gatos Union SD $4.07 + Los Gatos-Saratoga Union HSD $1.66 per sq ft[6][7][8] LGUSD charges nothing on remodels under 500 sq ft. Campbell Union HSD ($1.61) also lists Los Gatos. Check which districts serve your parcel.
Sewer connection (West Valley Sanitation District) $6,727 max connection + $1,024 max treatment plant capacity[9] Smaller ADUs pay $511.16 and $73.53 per drainage fixture unit. The district's fee tables are labeled FY2018/19 to FY2020/21.
Water (San Jose Water) No published ADU fee[10] San Jose Water quotes new service installation costs case by case.
School fee rates for districts in Los Gatos (4)

District lines in Los Gatos were not checked against a boundary map. Campbell Union HSD lists Los Gatos; Campbell Union SD's coverage of the town is not confirmed.[8][7]

  • Los Gatos Union School District[6]Remodels under 500 sq ft pay nothing. $4.07/sq ft
  • Los Gatos-Saratoga Union High School District[7] $1.66/sq ft
  • Campbell Union High School District[8] $1.61/sq ft
  • Campbell Union School District[11]Charges ADUs over 500 sq ft. $3.79/sq ft
Total cost in Los Gatos, fees plus building

How the permit works

  1. 1

    Check the rules

    Read the Town's ADU brochure, and check whether the 2026 draft ordinance has been adopted.[1][3]

  2. 2

    Prepare one combined ADU/JADU application

    One application and one plan review cover Planning and Building.[12]

  3. 3

    Submit a Building pre-application online

    File on the Town permit portal. Fees are invoiced before review starts.[12]

  4. 4

    Plan review

    The Town routes your plans to its departments and to outside agencies such as West Valley Sanitation District and County Fire. Expect more than one round.[12]

State deadline: State law gives the Town 15 business days to say if your application is complete and 60 days to approve or deny a complete one.[13]

Apply at: Los Gatos permit portal

Preapproved plans

The Town has an ADU Plans Gallery of pre-approved plans. You can't change a pre-approved plan.[3]

We could not read the gallery's plan list, and no prices are published.

Common questions

What are the Los Gatos ADU requirements?

An ADU can be 1,200 sq ft, with 4 ft side and rear setbacks and 5 ft from other buildings. Most ground-floor ADUs are capped at 16 ft. You need 1 parking space unless an exception applies.[1]

How big can an ADU be in Los Gatos?

1,200 sq ft. Up to 800 sq ft doesn't count toward your floor area, and a junior ADU can be up to 500 sq ft.[1]

Do I need parking for an ADU in Los Gatos?

Usually 1 space, which can be in the driveway or tandem. Town Code 29.10.320(f)(1) lists exceptions. A junior ADU needs none.[1]

How much is the Los Gatos ADU permit cost?

The Town publishes no total. The building permit comes from valuation, plus 65% for plan review and 15% for Title 24. ADUs under 750 sq ft pay no traffic impact fee; sewer connection runs up to $6,727 plus $1,024.[2][1][9]

Are the Los Gatos ADU rules changing?

Yes. The Planning Commission recommended a new ADU ordinance on June 10, 2026, and the Town Council was due to review it on August 4, 2026.[3]

Nearby cities

What we couldn't confirm

  • Outcome of the Aug 4, 2026 Town Council review of the draft ADU ordinance not posted.
  • No Town-published ADU review time.
  • Pre-approved gallery plans and prices not captured.
  • The trip rate used for the traffic impact fee on an ADU is not published.
  • West Valley Sanitation fee amounts newer than the FY2020/21 tables not confirmed.
  • School district lines within the Town not checked against a boundary map.
  • No Town contact email or phone recorded for ADU questions.

Sources

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

  1. 1. Town of Los Gatos 1,200 sq ft max Checked Oct 18, 2026
  2. 2. Town of Los Gatos Building valuation method, plan review 65%, Traffic Impact Mitigation Fee $1,128/ADT, construction taxes Checked Oct 18, 2026
  3. 3. Town of Los Gatos ADU ordinance update status Checked Oct 18, 2026
  4. 4. Town of Los Gatos Linked draft ordinance (not analyzed) Checked Oct 18, 2026 read from an archived copy of this official page
  5. 5. Town of Los Gatos Planning plan check 20% of building fee Checked Oct 18, 2026
  6. 6. Los Gatos Union SD Residential $4.07/sq ft Checked Oct 18, 2026
  7. 7. Los Gatos-Saratoga Union HSD $1.66/sq ft as of June 15, 2026 Checked Oct 18, 2026
  8. 8. Campbell Union HSD $1.61/sq ft eff Checked Oct 18, 2026
  9. 9. West Valley Sanitation District ADU connection $6,727 max/$511.16 per DFU Checked Oct 18, 2026
  10. 10. San Jose Water Water Services Department works with homeowners on new service Checked Oct 18, 2026
  11. 11. Campbell Union SD Residential & ADU $3.79/sq ft Checked Oct 18, 2026
  12. 12. Town of Los Gatos Portal URL Checked Oct 18, 2026
  13. 13. 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