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When a permit is required
Permit triggers and exempt work for San Mateo County
A permit is needed when a building/structure will be erected, constructed, enlarged, altered, repaired, moved, improved, removed, converted, or demolished.
Note: - Confirm exemptions directly against the Building Ordinance before starting construction. - Even where no building permit is required, a planning permit, environmental review, or other agency approval may still apply.
- Plans are submitted online in PDF and include plot, foundation, floor, elevation, and detail sheets with minimum scales, property identification, surveys if required, energy/fire/engineering information, and code-specified technical details.
- Building code
- The County adopts and enforces IBC/California Title 24 family codes (2022 editions at ordinance level), the 2022 California Energy Code/Green Building Code and local amendments in Division VII for unincorporated areas.
- Permit validity
- New residences/additions are valid for 1 year and may be renewed once for a second year without extra fee; many smaller permits are also valid for 1 year to start construction. A progress inspection is required at least every 180 days and permits expire if extensions are not requested before expiry.
- Owner-builder
- Workers’ Compensation coverage must be provided each time a permit is applied for. If claiming an exemption and hiring a contractor, owner-builders must provide contractor name, license number, and mailing address.
- Contractor requirements
- If a licensed-contractor exemption is used, contractor license information is required. Architect/engineer identification/license must be shown on plans where design sheets are required by permit type.
Application process
Typical processing: initial completeness review ~5 days; review agencies generally complete plan checks within 30 days for building permits.
- 01 Apply for building permit online.
- 02 County staff checks for complete submittal and initial fees (typically within 5 days for building permits).
- 03 Referral and plan check by required agencies (Planning, Public Works, Fire, Civil/Drainage, Geotechnical) with a typical 30-day agency review target.
- 04 Resubmittal and resubmission if comments are issued.
- 05 Permit issuance after required plan checks pass and final fees are paid.
- 06 Inspections scheduled; final inspection at completion before occupancy/use of the permitted area.
- 07 Scope changes may trigger a revisions cycle.
Typical processing time: initial completeness review ~5 days; review agencies generally complete plan checks within 30 days for building permits.
Fee schedule
San Mateo County building permit fees
Pay online (card or bank, fees may apply), or by mail/check to the County with permit/record number; also available at county office during business hours.
Fees change periodically. Confirm at the official fee schedule ↗ before budgeting.
Required inspections
Scheduling and sequence
- Accela Citizen Access (county permit system) (online)
- (650) 599-7311 (phone)
- Time windows
- Inspections are generally scheduled between 8:00 AM and 3:30 PM; 3-hour estimated time windows are published online on the day of inspection.
Typical sequence: initial inspections by trade phase, progress inspections during active work, and a final inspection prior to occupancy/use.
Frequently asked
Common questions about unincorporated San Mateo County permits
01 Do I need a building permit in unincorporated San Mateo County, CA? ▸
02 How much does a building permit cost in unincorporated San Mateo County, CA? ▸
03 How do I apply for a building permit in unincorporated San Mateo County, CA? ▸
04 How long does it take to get a building permit in unincorporated San Mateo County, CA? ▸
05 How do I schedule a building inspection in unincorporated San Mateo County, CA? ▸
Educational reference. Permit rules and fees change — confirm current requirements directly with San Mateo County Planning and Building Department before applying. Jaspector is not legal advice.