ADU permit process in San Carlos, California

San Mateo County, California

Prepared by GetYourPermit editorial teamReport an error

We haven’t written San Carlos’s permit guide yet.

We publish permit process guides one city at a time, and we would rather publish nothing than guess at San Carlos’s rules using another city’s process. Permit steps, submittal requirements, and review timelines are set locally, so a guide copied from a neighboring city would be wrong in ways that cost you time.

Here is what is useful for San Carlos right now.

See the fee estimate for San Carlos

Start here instead — official and primary sources for San Carlos

CityFY 2026-27 Cost of Services — Building Department Fees
The City adopted FY 2026-27 Building Department schedule is effective July 1, 2026 and lists separate valuation bands for building permit and plan check.
Accessed August 28, 2026
CityBuilding an Accessory Dwelling Unit
The City states ADU/JADU applications go directly to Building and no impact fees are collected for an ADU below 750 square feet or a JADU.
Accessed August 28, 2026

What to ask the San Carlos building department

The current building permit fee schedule, and the date it took effect.
Whether development impact fees apply at your square footage — many California cities waive them for ADUs of 750 sq ft or less.
Plan submittal requirements: what drawings they expect, in what format, and whether submittal is online or in person.