Cal. Gov. Code § 15624
When requested by the legislative body of any county, city, or city and county or the assessor to render advisory or other service, other than those services specified in this chapter, the board may contract, at not less than cost and subject to regulations approved by the Director of General Services, to render such services.
In addition to any other service the board may render under this section, it is the intent of the Legislature that the board furnish auditor and appraisal personnel, on request, to local taxing authorities to aid in making postaudits of personal property. The board shall report to the Legislature annually on all requests received under this section and the disposition of these requests.
All money received by the Board of Equalization pursuant to such contracts shall be paid into the State Treasury to the credit and in augmentation of the current appropriation of the board.
Ca. Gov. Code § 15624