Cal. Educ. Code § 35168

The governing board of each school district, shall establish and maintain a historical inventory, or an audit trace inventory system, or any other inventory system authorized by the State Board of Education, which shall contain the description, name, identification numbers, and original cost of all items of equipment acquired by it whose current market value exceeds five hundred dollars ($500) per item, the date of acquisition, the location of use, and the time and mode of disposal. A reasonable estimate of the original cost may be used if the actual original cost is unknown.