California Code, Education Code - EDC § 26301

(a) Employers shall report contributions paid on behalf of each participant in each pay period, along with all other information required by the system no later than 10 working days following the last day of the pay period in which the salary was earned, and the report shall be delinquent immediately thereafter.  That report shall be submitted electronically in an encrypted format provided by the system that ensures the security of the transmitted participant data.

(b) The board shall, in accordance with regulations, assess a penalty against the employer for a report submitted late or in an unacceptable form.  The penalty shall be based upon the sum of the employee and employer contributions required to be reported under this part at a rate of interest equal to the regular interest rate, accruing on the balance for the period between the time the report was due and the time an acceptable report is actually received by the system.