Cal. Public Utilities Code § 274

The commission may on its own order, whenever it determines it to be necessary, conduct audits or reviews of the revenues required to be collected and submitted to the commission for each of the funds specified in Section 270. The commission may on its own order, whenever it determines it to be necessary, conduct audits or reviews on the compliance with commission orders with regard to each program subject to this chapter. The commission shall apply a risk-based methodology to conduct audits or reviews of program-related costs and activities. This section does not limit the commission’s authority to initiate an audit or review when circumstances warrant doing so. The commission may contract with the California State Auditor’s Office, the Department of Finance, or another qualified audit or consulting firm for any necessary auditing or review services if the commission’s own auditing services are not available. All costs for audits or reviews shall be paid from the fund that supports the activities of the board audited or reviewed and shall be subject to the availability of money in that fund.