Cal. Health & Safety Code § 13904

If a warrant is presented to the district treasurer for payment and the treasurer cannot pay it for want of funds in the account on which it is drawn, the treasurer shall endorse the warrant “NOT PAID BECAUSE OF INSUFFICIENT FUNDS” and sign his or her name and indicate the date and time the warrant was presented. From that time until it is paid, the warrant bears interest at the maximum rate permitted pursuant to Article 7 (commencing with Section 53530) of Chapter 3 of Part 1 of Division 2 of Title 5 of the Government Code.