Random drug testing is against the law in California. You cannot require your employees to take a random drug test, and you must give your employees notice before a drug test is given. There is one exception to this rule, as employees in public jobs may be required to take a drug test if public safety is a concern.
As a condition of employment, finalists for full-time, part-time, extra help, contingent workers (i.e. agency temporary employees), and temporary positions will be required to successfully pass pre-employment background investigation, medical examinations, drug screening, Department of Motor Vehicles (OMV) license ...