Compare · checked Oct 18, 2026

San José vs Santa Clara ADU fees: San José $14,045–$29,202 vs Santa Clara $9,572–$15,446 in modeled fees for 1,000 sq ft

Modeled from each place’s official fee schedules for a detached ADU next to a 2,000 sq ft main home (example assumption), law in force today. Ranges count fees that always apply (low) and fees that may apply (high). Not like for like: Santa Clara: Totals leave out park and traffic impact fees over 750 sq ft.

Modeled fee totals by ADU size

	San José	Santa Clara	Lower
499 sq ft	$7,030–$9,608	$5,065–$5,559	Santa Clara by $4,048
750 sq ft	$8,785–$15,397	$7,290–$11,819	Santa Clara by $3,578
1,000 sq ft	$14,045–$29,202	$9,572–$15,446	Santa Clara by $13,756
1,200 sq ft	$15,443–$31,676	$10,406–$17,356	Santa Clara by $14,320

Where the money goes at 1,000 sq ft

	San José	Santa Clara
Planning & zoning	$0–$449	$1,035
Building permit & plan check	$5,103–$6,372	$6,650
Public works & encroachment	–	$0–$494
Construction taxes	$7,242–$7,321	–
Impact fees	$1,700–$8,900	–
School district fee	$0–$5,380	$0–$5,380
Utility connections	$0–$780	$1,887
Impact fees under SB 1117 (from 2027)	$2,225	$0
ADU permits issued, 2025	502	140

Line-by-line figures with the quoted source text: San José · Santa Clara. Permits: HCD Annual Progress Report data.

Rules side by side

	San José	Santa Clara
Maximum size	Detached ADU: 1,000 sq ft on lots under 9,000 sq ft; 1,200 sq ft on lots over 9,000 sq ft. JADU: 500 sq ft.	State floor: cities must allow at least 850 sq ft (1,000 sq ft with 2+ bedrooms); detached ADUs can be capped at 1,200 sq ft.
Height	Detached ADU: 18 ft for one story, 25 ft for a second story; up to 2 stories.	State floor: 16 ft detached (18 ft near transit or on a multifamily lot, +2 ft for roof pitch); 25 ft attached.
Setbacks	Side and rear: 4 ft. Front: the zoning district's setback (Table 20-60). Behind the main home or 45 ft from the front; max 40% rear-yard coverage; 6 ft between buildings.	State limit: no more than 4 ft side and rear.
Parking	None required.	State limit: at most 1 space per ADU or bedroom, and none within ½ mile of transit and in other cases.
Owner occupancy	Not required for an ADU. Owner-occupancy of the main home is required for a JADU that shares sanitation.	State law: cities can't require the owner to live on site for an ADU (JADUs: owner on site if sanitation is shared).
Pre-approved plans	San José runs a Preapproved ADU program of plans already reviewed by the City.	State law: every city must run a program to pre-approve ADU plans (Gov. Code 65852.27).

Grey text is the state floor where we haven’t captured the local rule yet.

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FAQ

San José vs Santa Clara: questions

Are ADU fees higher in San José or Santa Clara?

For a detached 1,000 sq ft ADU with a 2,000 sq ft main home, our model of the official schedules gives San José $14,045–$29,202 and Santa Clara $9,572–$15,446. Santa Clara: Totals leave out park and traffic impact fees over 750 sq ft.

Which charges more impact fees on an ADU, San José or Santa Clara?

At 1,000 sq ft: San José $8,900, Santa Clara $0 (proportional to a 2,000 sq ft house). Neither can charge impact fees at 750 sq ft or less. From 2027, SB 1117 limits them to the area over 750 sq ft: $2,225 and $0 in our model.

What does a 750 sq ft ADU cost in fees in each?

San José: $8,785–$15,397. Santa Clara: $7,290–$11,819. At 750 sq ft or less, state law bars impact fees in both.

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