California Code, Financial Code - FIN § 17409.1

(a) Each person subject to this chapter shall maintain separate escrow trust accounts for each licensed location.  Transfers between accounts are prohibited except by the actual writing of a check from one escrow to the other, and by depositing the check for the account of, and the writing of a receipt for the escrow to which the funds are being transferred.  Each transfer shall be properly supported and documented in escrow files by inclusion of escrow instructions executed by the principals authorizing the transfer.

(b) With regard to Internet escrow companies, transfers to trust accounts by commercial banks and from operating accounts to cover losses may be made through wire transfer.  Receipts for all these transactions may be maintained in electronic form.