California Special Licenses

If any of the following are true, you will need a CDL.

A vehicle with a Gross Vehicle Weight Rating (GVWR) of 26,001 pounds or more.
A combination vehicle with a gross combination weight of 26,001 or more pounds with the GVWR of the towed vehicle(s) in excess of 10,000 pounds.
Any vehicle that tows any vehicle with a GVWR of 10,001 pounds or more.
Any vehicle that tows more than one vehicle or a trailer bus.
A vehicle designed to transport 10 or more passengers including the driver.
Any vehicle which requires HAZMAT placards or is carrying material listed as a select agent or toxin in Title 42, Code of Federal Regulations.

There are exceptions to these rules such as:

Persons operating a vehicle in an emergency situation at the direction of a police officer.
Drivers of house cars over 40 feet but not over 45 feet, with an endorsement.
Non-civilian military personnel operating military vehicles.
Implement of husbandry operators who are not required to have a driver's license.
Vanpools.
And more...

Some vehicles may also require a certificate or endorsement along with a CDL in order to be driven legally.

School Bus Drivers - must have a school bus endorsement ("S").
Shuttle Bus Drivers - may need additional certificates; check with your potential employer.
Taxi Cab Drivers - may have extra requirements based on your local government.
Chauffeur - depends on the vehicle.
Tank Vehicles such as a Cement Truck require an "N" endorsement.
HAZMAT vehicles require an "H" endorsement.

Be a California resident.
Must be 18 years of age.
Must be 21 years of age to drive a commercial vehicle engaged in interstate commerice or to transport hazardous materials or wastes.
Complete the Commerical Driver License Application (DL44C)
Complete an approved Medical Examination Report (DL51)

For more information, visit dmv.ca.gov.