Skip to content
Bay Area ADU Builders
Get quotes

What an ADU costs in Saratoga

Two numbers, kept apart. City fees come from the city's own fee pages. The build price is our estimate from the last owner survey and today's published prices. How we got it

Official City fees

Line by line

The city doesn't publish a total for an ADU, so we list each charge.See every fee [1]

Our estimate Building it

$350k–465k

750 sq ft detached, design and construction. Middle of the range: $405k.[2][3][4][5]

All in, before school and utility fees: about $350k to $465k for a 750 sq ft detached ADU. Adjust it for your lot

12 licensed builders list Saratoga on their own sites. Your quote request goes to the Bay Area ADU Builders team.

Get 3 quotes

Estimate your ADU

Change the type and size. City fees come from Saratoga's own averages; the building cost is our estimate.

Type
School districts
Building it (our estimate)
—
City permit fees (city average)
—
School fees (rate × the whole ADU once it's over 500 sq ft, capped at $5.38)
—
Likely total
—

Building (middle) City fees School fees

Not included: water and sewer connection, and site surprises like a long utility run or a crane. See the fee list below.

Get 3 quotes to check this number

Licensed builders who list Saratoga

All 12

The top three by our public score for Saratoga. Some publish prices, which is the quickest check on the estimate above.

Every fee Saratoga can charge

Building permit, by valuation $1,693 for the first $100,000, plus $9.60 per $1,000 up to $500,000[1] Valuation is the ICC table × 2.9. Fee schedule effective July 1, 2026.
Plan check and surcharges Plan check 66% of the permit fee; 8.10% technology surcharge; General Plan fee 0.285% of valuation; $170 address processing[1]
Park development fee $0 up to 750 sq ft; above that, a share of $56,845 scaled to the main home[1][6][7] The city's 2024 handout says ADUs under 700 sq ft are exempt; the newer web page says 750.
Below-market rent fee waiver All planning, building and engineering fees waived[1] Only for an ADU or JADU deed-restricted to below-market renters.
School fees Saratoga Union SD $0.70 + Los Gatos-Saratoga Union HSD $1.66 per sq ft[8][9][10] Saratoga Union SD charges nothing under 500 sq ft. Campbell Union HSD also lists Saratoga, and Cupertino Union, Fremont Union HSD and Moreland may serve some parcels. Check yours.
Sewer connection (West Valley Sanitation District) $6,727 max connection + $1,024 max treatment plant capacity[7][11] The city lists West Valley Sanitation as the sewer contact. Smaller ADUs pay $511.16 and $73.53 per drainage fixture unit.
Water No published ADU fee[7][12] The city says some ADUs need a new water or sewer connection. San Jose Water quotes new service costs case by case.

How we estimate the building cost

The last survey of what Bay Area owners actually paid is from UC Berkeley in 2021: a median of $329 per sq ft for ADUs permitted in 2018 and 2019.[2] Construction prices in California have risen about 60% since then by the state's own cost index (2018-2019 average 6,719 to September 2026: 10,717).[3] We check that against two current numbers and use the spread as the range.

  • UC Berkeley 2021 owner survey, Bay Area median for ADUs built 2018-19 ($329 per sq ft), raised by the California Construction Cost Index (x1.595)[2][3] $525/sq ft
  • San Mateo County ADU Resource Center rule of thumb for design, construction and fees[4] $450 to 600/sq ft
  • Abodu published all-in price, 800 sq ft 2 bed / 2 bath ($424,800)[5] $531/sq ft

Other ADU types

  • Attached ADU: Detached band scaled by the survey's addition-to-detached ratio ($250 vs $300 per sq ft statewide)[2] $375 to 500/sq ft
  • Garage conversion: UC Berkeley 2021 owner survey, statewide median for garage ADUs ($189 per sq ft), raised by the California Construction Cost Index[2][3] $302/sq ft
  • Garage conversion: Same, with the survey's Bay Area premium over the statewide median (x1.32)[2][3] $397/sq ft
  • Garage conversion: SYMBiHOM published garage conversion price, $150K to $225K (per sq ft at a 400 sq ft two-car garage)[13] $375 to 560/sq ft
  • Junior ADU: UC Berkeley 2021 owner survey, statewide median for converting part of the main home ($173 per sq ft), raised by the California Construction Cost Index[2][3] $276/sq ft
  • Junior ADU: Same, with the survey's Bay Area premium (x1.32)[2][3] $363/sq ft

Smaller units cost more per foot. We scale by size the way Abodu's own price list does. The survey counted design and permits in its figure, so a little of the city fee may overlap.

Prefab prices you can check

Abodu published all-in prices (home + typical installation).[5]

  • Studio, 385 sq ft$298,800
  • 1 bed, 500 sq ft$324,800
  • 2 bed / 1 bath, 625 sq ft$358,800
  • 2 bed / 2 bath, 800 sq ft$424,800
  • 3 bed / 2 bath, 1,070 sq ft$464,800
  • 3 bed / 3 bath, 1,195 sq ft$498,800

Not included: Survey package ($6,000), trenching past 50 ft, crane past 100 ft, demolition, site engineering and sales tax.

What other sites say

  • 9Builders: $150,000 to $350,000 in San Jose[14]
  • IMKAT Homes: $205,000 to $415,000 by size[15]
  • ADU Builders Group: $450 to $475 per sq ft[16]
  • SYMBiHOM: $250,000 to $500,000 for a 500 to 1,200 sq ft backyard ADU[13]

None of these pages cites where its number comes from.

Common questions

How much does it cost to build an ADU in Saratoga?

For a 750 sq ft detached ADU, our estimate is $350,000 to $465,000 to build. School and utility fees can add more.[1][2][3][4]

What are the ADU permit fees in Saratoga?

The city doesn't publish a total. No published total; see fee lines The fee lines on this page list each charge.[1]

Do ADUs under 750 sq ft pay impact fees?

No. State law bars impact fees on ADUs under 750 sq ft. Larger ADUs pay in proportion to the main home. School fees follow a different rule, and districts disagree about it, so ask yours.[17]

Is a garage conversion cheaper than a new ADU?

Usually. In the 2021 UC Berkeley survey, garage ADUs had a median cost of $90,000 statewide against $180,000 for detached ones. Raised to 2026 prices, a 400 sq ft garage conversion lands around $120k to $225k by our estimate.[2][3][13]

Saratoga ADU rules and builders Compare fees across cities

Sources

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

  1. 1. City of Saratoga Building valuation x2.9, plan check 66%, tech 8.10%, GP 0.285%, park dev fee $56,845/SFR, deed-restricted ADU Checked Oct 18, 2026
  2. 2. UC Berkeley Center for Community Innovation Statewide median $150,000/$250sf Checked Oct 18, 2026 read from an archived copy of this official page
  3. 3. California Department of General Services California Construction Cost Index (ENR BCI average of San Francisco and Los Angeles) Checked Oct 18, 2026
  4. 4. San Mateo County ADU Resource Center $450-$600/sf all-in placeholder Checked Oct 18, 2026
  5. 5. Abodu Home From $234,800 Checked Oct 18, 2026
  6. 6. City of Saratoga Standards, process, impact-fee rule (750 sq ft), waivers Checked Oct 18, 2026
  7. 7. City of Saratoga 15-day feedback Checked Oct 18, 2026
  8. 8. Saratoga Union SD $0.70/sq ft Checked Oct 18, 2026
  9. 9. Los Gatos-Saratoga Union HSD $1.66/sq ft as of June 15, 2026 Checked Oct 18, 2026
  10. 10. Campbell Union HSD $1.61/sq ft eff Checked Oct 18, 2026
  11. 11. West Valley Sanitation District ADU connection $6,727 max/$511.16 per DFU Checked Oct 18, 2026
  12. 12. San Jose Water Water Services Department works with homeowners on new service Checked Oct 18, 2026
  13. 13. SYMBiHOM Garage conversion $150K-$225K Checked Oct 18, 2026
  14. 14. 9Builders FAQ: SJ ADU $150k-$350k, rents $1,800-$3,000/mo, unsourced Checked Oct 18, 2026
  15. 15. IMKAT Size-tier cost table $205k-$415k, unsourced Checked Oct 18, 2026
  16. 16. ADU Builders Group $450-$475/sq ft Checked Oct 18, 2026
  17. 17. 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