ADU permit guide for Los Altos Hills, California
Santa Clara County, CaliforniaReviewed August 28, 2026
Building Department reviews local ADU permits through the City Online Portal System. Use this page to plan the local process and the fee questions to verify before you submit.
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Permit fee planning by size
GetYourPermit research · 1 published reference line
| ADU size | Researched range |
|---|---|
| 600 sq ft | $7,100 – $18,800 |
| 800 sq ftimpact-fee band | $11,300 – $29,800 |
| 1,000 sq ft | $13,600 – $36,100 |
| 1,200 sq ft | $15,900 – $42,400 |
Getting the permit
- Department
- Building Department
- Where to apply
- City Online Portal System