California Code, Labor Code - LAB § 1030

Every employer, including the state and any political subdivision, shall provide a reasonable amount of break time to accommodate an employee desiring to express breast milk for the employee's infant child each time the employee has need to express milk.  The break time shall, if possible, run concurrently with any break time already provided to the employee.  Break time for an employee that does not run concurrently with the rest time authorized for the employee by the applicable wage order of the Industrial Welfare Commission shall be unpaid.