California Code, Financial Code - FIN § 1409

When a statement of account has been rendered by a bank to a depositor accompanied by vouchers, if any, which are the basis for debit entries in such account, such account shall, after the period of four years from the date of its rendition, in the event no objection thereto has been theretofore made by the depositor, be deemed finally adjusted and settled and its correctness conclusively presumed and such depositor shall thereafter be barred from questioning the correctness of such account for any cause.

A statement of account within the meaning of this section shall be deemed to have been rendered on a savings or time account when the bank, by making a notation in the depositor's bank book or in some other manner reasonably calculated to give notice thereof to the depositor indicates that a certain sum is the correct balance of the account.

Nothing herein shall be construed to relieve the depositor from the duty now imposed by law of exercising due diligence in the examination of such account and vouchers, if any, when rendered by the bank and of immediate notification to the bank upon discovery of any error therein, nor from the legal consequences of neglect of such duty;  nor to prevent the application of subsection (3) of Section 340 of the Code of Civil Procedure to cases governed thereby.