ADU builders in Sunnyvale, California

Sunnyvale does not publish a fee schedule specific to accessory dwelling units. What follows is from its general schedule (FY 2025/26), so expect to confirm the figures with the permit counter. These are city fees only. They do not include what a builder charges to design and build the unit.

Plan check

basis percentage of building permit fee
detail Plan Check = 70% of the Building Permit Fee. Energy Plan Check = 10% of the Building Permit Fee. Fire Prevention Permit = 70% of the Building Permit Fee. Plan Check Resubmittal $255/hour (two-hour minimum).
as of 2025-08-18

Building permit

basis valuation-based table; valuation set by Building Division adopted valuation tables
detail $1-$2,000: $157.00 for the first $2,000. $2,001-$25,000: $260.00 for the first $2,000 plus $31.50 per additional $1,000. $25,001-$50,000: $988.00 for the first $25,000 plus $23.00 per additional $1,000. $50,001-$100,000: $1,558.00 for the first $50,000 plus $16.50 per additional $1,000. $100,001-$500,000: $2,351.00 for the first $100,000 plus $13.00 per additional $1,000. Plus Permit Issuance $41.00 and Technology Surcharge 5% of permit fee. Separate Mechanical, Electrical and Plumbing permits at $0.14/sq ft residential, $125.00 residential minimum each.
additional charges Construction Tax 0.54% of total valuation and General Plan Maintenance 0.15% of total valuation, both charged for all projects other than residential remodels.
as of 2025-08-18

School district fees

rate Set by the State of California and assessed by the applicable district; the City does not publish the rate. Elementary/middle districts in Sunnyvale: Sunnyvale SD, Santa Clara USD, Mountain View-Whisman SD, Los Altos SD, Cupertino Union SD. High school districts: Fremont Union HSD, Mountain View-Los Altos UHSD.
threshold stated by city School Impact Fee: Required for new construction ADUs with 500 sq. ft. or more living area and shall be paid to the applicable school district.
source Sunnyvale ADU brochure; Development Impact Fees sheet, School Impact Fees section
as of 2025-08-18

Utility connections

verbatim Utility Hookups: Incremental sewer and water connection fees are exempt. If total water closets for the site exceeds 5, building sewer system to be upgraded to 4" line with building and property line cleanouts.
separate connection required Not required. Detached ADU sewer line may pass through the primary dwelling; new line to connect down line of the primary dwelling kitchen island sink; no ejector pump allowed. Attached ADUs connect to the existing lateral.
utility billing note For utility rate purposes, single-family with ADU properties are classified as multi-family properties with two units, effective the day the ADU project is completed and signed off.
source Sunnyvale ADU brochure (SUNNYVALE HOMEOWNERS: INTERESTED IN BUILDING AN ACCESSORY DWELLING UNIT?)

Impact fees

under 750 language verbatim Transportation Impact Fee (TIF): Required for all ADUs over 750 square feet.
source url https://www.sunnyvale.ca.gov/home/showpublisheddocument/1766/637883105208670000
applicable rates if over 750 Transportation Impact Fee, South of Route 237: Single-Family, detached $4,899/unit; Multi-family, attached $3,037/unit (FY 2025-2026, effective 2025-08-18). Park In-Lieu Fee, low density (7 or fewer du/net ac): $77,863.50 per unit.

Sunnyvale fee scheduleFee schedule PDF

Common questions

These came up when looking for ADU builders in Sunnyvale but did not meet the bar for the list above, usually because they do not advertise a California licence number, do not name Sunnyvale as an area they serve, or do not present accessory dwelling units as a service they offer. They are shown so the list above can be checked rather than taken on trust.

• ADU Builders Bay Area near miss
• ADU Construction near miss
• ADU Gurus near miss
• Advanced Construction Pro Inc near miss
• Alcon Home Remodeling near miss
• Ataman Studio near miss
• BUILD 33 near miss
• Barcci Builders near miss
• Baron Construction and Remodeling Co. near miss
• Bay Area Realty & Construction near miss
• Bay Builders & Remodeling, Inc. near miss
• Construction & More ADUs near miss
• Cottage Technologies, Inc. near miss
• Cupertino ADU Solutions near miss
• Direct Home Remodeling, Inc. near miss
• Done Right Builders and Remodeling near miss
• EBCON Corporation near miss
• EDR Design Build near miss
• Eco Scale Construction near miss
• Edwards Home Remodeling near miss
• Greenberg Construction near miss
• HAUS+ near miss
• HDR Remodeling Inc. near miss
• HomeTech Construction & Design near miss
• Integrum Construction near miss
• Lavan Construction near miss
• MA Legacy Remodeling near miss
• May Construction, Inc. near miss
• Nestadu near miss
• New Avenue Homes near miss
• New Key Construction near miss
• Next Stage Design + Build near miss
• San Jose ADU Solutions near miss
• Solace Design & Build near miss
• Sunrooms N More near miss
• Talmadge Construction, Inc. near miss
• USModular, Inc. near miss
• WISE Builders near miss
• ADU Homes
• ADU Homes, Inc.

1. Look the licence up yourself at cslb.ca.gov. It takes under a minute and shows the current status, any suspensions, and the bond.
2. Ask who carries workers’ compensation for the crew and for every subcontractor. A licensee with no employees may lawfully be exempt, but if someone is hurt on your property you can end up treated as the employer.
3. Ask for two recent permit numbers in any city, then look them up. A builder who has done the work can produce them immediately.
4. Get the price in writing against a drawing set. A published starting price is for a base model and rarely includes site work, utilities, or Sunnyvale fees.