Cupertino · Santa Clara County
ADU Design & Build in Cupertino, California
Cupertino's strong schools and steady rental demand make ADUs one of the highest-ROI moves a homeowner can make on the peninsula.
Building ADUs in Cupertino, California
SHAPE designs and builds accessory dwelling units for homeowners in Cupertino, California, across Monta Vista, Rancho Rinconada, Garden Gate, Fairgrove, and the neighborhoods around Cupertino High and Homestead.
Cupertino's schools are a national magnet, and Apple's presence keeps rents at Peninsula highs. Detached ADUs here rent quickly, and many are built for multigenerational families.
We're a licensed California general contractor (CSLB #1158688) with an in-house architecture and modular construction team. That means one contract, one fixed price, and one team responsible from the first site walk through final inspection with the Cupertino building department.
Cupertino ADU Rules at a Glance
- Setbacks: California state law caps rear and side setbacks for new ADUs at 4 feet, and Cupertino follows that standard.
- Height: Streamlined detached ADUs can be 18 feet tall, or 20 feet within half a mile of transit. Attached ADUs can reach 25 feet or the main house's height, whichever is lower.
- Maximum size: A streamlined detached ADU of up to 800 sq ft is exempt from floor area, lot coverage and open space limits. Larger ADUs can be 850 sq ft with a studio or one bedroom and 1,000 sq ft with two or more, and attached ADUs over 800 sq ft cannot exceed 50% of the main home.
- JADUs: Junior ADUs (up to 500 sq ft) are allowed inside the existing footprint of the primary home, in addition to a detached ADU on most single-family lots.
- Units allowed: Up to three ADUs and junior ADUs, in any combination, on a single-family lot. A junior ADU cannot go in a garage.
- Design standards: Objective design standards apply only in the Planned Development, R1-e (Eichler), Monta Vista, RHS hillside and R1-a zones.
- Spacing: At least 5 feet between the eaves of the ADU and the main house, and 4 feet from side, rear and street-side lines.
- Parking: No replacement parking is required when a garage or carport is converted or torn down to build an ADU, wherever the lot is. Separately, no parking can be required for the ADU itself within one half-mile walking distance of public transit.
Rules checked September 2026 against: Cupertino ADU ordinance, September 2025, Cupertino ADU FAQ, Cupertino ADU development standards, Cupertino pre-approved plans, Cupertino FY2025-26 building fees, Cupertino tree protection, Cupertino Union School District developer fees, Santa Clara County Assessor, HCD ADU Handbook, California Energy Commission ADU guidance. City rules change often. We confirm the rules for your lot before design.
SHAPE handles the full permit package with the Cupertino planning department, zoning verification, building plans, Title 24 energy, and every correction cycle, so you don't have to learn the code.
Our Process
- Site assessment. We walk your Cupertino lot, confirm setbacks and utility locations, and give you a feasibility read and an all-in price the same week.
- Design. Our in-house architects design the ADU around your lot, your family, and your budget, with fixed pricing before you sign.
- Permits. We submit, respond to every planning and building comment, and drive the file to permit issuance with Cupertino.
- Build. Modules are fabricated in our facility while site work, foundation, utilities, landscaping, runs in parallel. Set and finish happen on site.
Costs beyond the building in Cupertino
These are Cupertino's own fees, separate from the building price. We include the ones your project needs in the fixed quote.
| Item | Amount |
|---|---|
| ADU plan check, up to 499 sq ft (FY2025-26) | $2,691 |
| ADU plan check, 500 to 999 sq ft | $3,908 |
| ADU inspection, up to 499 sq ft | $2,865 |
| ADU inspection, 500 to 999 sq ft | $4,010 |
| Planning review | 20% on top of the building fees |
| City impact fees | Waived for ADUs under 750 sq ft |
| Cupertino Union School District fee (on space over 500 sq ft) | $3.10 per sq ft |
Eichlers, hillsides and trees in Cupertino
Most Cupertino ADUs are simple, but three conditions change the rules.
- Eichler and special zones: in the R1-e (Eichler), Monta Vista, RHS hillside, R1-a and Planned Development zones, the ADU must meet objective design standards. Elsewhere it does not.
- Hillside and hazard areas: Cupertino's pre-approved plans are limited to the valley floor and exclude fault-rupture, slope-instability, hillside and liquefaction zones, so foothill lots need a custom design.
- Protected trees: native oaks, California buckeye, big-leaf maple, deodar and blue atlas cedar, western sycamore and bay laurel are protected from 12 inches in diameter on a single trunk or 24 inches on multiple trunks, along with heritage trees and trees required by earlier approvals.
Frequently asked
- How much does an ADU cost in Cupertino?
- SHAPE's published prices start at $223,000 for Model 1, $263,000 for Model 2, and $343,000 for Model 2X on a typical lot. The final fixed quote in Cupertino depends on size, finishes, utilities, access, and site conditions.
- How long do permits take in Cupertino?
- California law requires ministerial ADU review within 60 days of a complete submittal. Real-world timelines in Cupertino typically run 2–4 months including corrections. SHAPE manages every submittal and response with the Cupertino planning department.
- Do I need to add parking for an ADU in Cupertino?
- Often, no. No parking can be required for an ADU within a half-mile walking distance of public transit, and no replacement parking is required when a garage or carport is converted or torn down to build the ADU. We check your lot's distance to transit during feasibility.
- What size ADU can I build in Cupertino?
- Under Cupertino's September 2025 ordinance, a streamlined detached ADU of up to 800 sq ft skips floor area and lot coverage limits, and larger ADUs can be 850 sq ft with one bedroom or 1,000 sq ft with two or more. On top of local rules, California state law guarantees at least 800 sq ft on most single-family lots regardless of local FAR limits.
- Can I rent out an ADU in Cupertino?
- Yes. California state law allows long-term (30+ day) rentals of ADUs statewide. Short-term rentals are set by the city, Cupertino, like most Bay Area jurisdictions, restricts or prohibits stays under 30 days.
- Can I build a two-story ADU in Cupertino?
- Cupertino's September 2025 ordinance allows a two-story ADU when converting an existing second floor, or for new construction within half a mile of a major transit stop. The city's FAQ describes two stories more broadly, so we confirm with Planning for your lot before design.
- I live in an Eichler. Are the rules different?
- Yes. In the R1-e Eichler zone, an ADU has to meet Cupertino's objective design standards, which cover how the ADU relates to the house. Outside the five special zones, those standards do not apply.
- Can Cupertino review my plans before I apply?
- Yes. Cupertino offers a free, optional preliminary review. Plans go by email to the Planning Division, and we use it to catch issues before the formal submittal.
- Can I turn my garage into a junior ADU?
- No. In Cupertino a junior ADU has to sit entirely inside the house, and garages do not qualify. A garage can become a full ADU instead.
- Does Cupertino have pre-approved ADU plans?
- Yes, a handful of detached plans from outside vendors, from about 476 to 991 square feet. They only work on the valley floor, not in fault, slope, hillside or liquefaction zones. We can compare one with a custom design on your lot.
- How many bedrooms can a Cupertino ADU have?
- State law does not let cities cap the number of bedrooms in an ADU. Above 800 square feet, two or more bedrooms raises Cupertino's size limit from 850 to 1,000 square feet.
- Does a Cupertino ADU need solar panels?
- A new detached ADU does. Under the 2025 California Energy Code it needs new solar panels, which can be added to an existing system elsewhere on the property. An attached ADU counts as an addition and does not need solar.
- Will an ADU raise my property taxes in Cupertino?
- Only on the new building. The Santa Clara County Assessor does not reassess the existing home. It assesses the ADU at market value when it is finished, or partly on January 1 if construction is still underway.
- Can I sell the ADU separately?
- No. Cupertino's ordinance allows ADUs to be rented but not sold separately, outside the narrow cases state law provides.
- Can I legalize an older unpermitted unit in Cupertino?
- Often, yes, if it was built before 2020. State law (AB 2533) bars impact fees and penalties for those units, though the city can deny one that is substantially unsafe. The state asked Cupertino in 2025 to add these provisions to its code.
- Is the California $40,000 ADU grant still available?
- No. CalHFA's ADU Grant paid up to $40,000 toward predevelopment costs, and CalHFA says its latest round was fully allocated in December 2023. CalHFA warns that anyone offering to get you one is running a scam.
- How long does PG&E take to connect an ADU?
- PG&E reported ADU electric hookups averaging about 300 days from request for projects finished by August 2025, and says its average for new service had dropped to 118 days by March 2026. We file with PG&E when the permit goes in so power is not the last thing we wait on.
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