California law requires employers to reimburse employees for expenses incurred to do their job. These expenses include, but are not limited to, mileage reimbursement for miles driven. Although many employers provide some mileage reimbursement, the amount paid does not compensate for all costs incurred by employees to drive their personal cars for work. A typical rate of reimbursement is the rate that is set by the Internal Revenue Service. If an employer does not reimburse at this rate, opting instead to use some sort of lump sum reimbursement system or a lower rate of reimbursement per mile driven, employees may be entitled to additional reimbursement.
California law also provides that any agreement to waive a right to reimbursement for expenses incurred on the employee's behalf is void and unenforceable.