Cal. Pub. Resources Code § 14591.3
In any civil or administrative action brought pursuant to this division in which the department prevails, the department may assess against the defendant or respondent any costs and fees, including attorneys' and experts' fees, and the cost of the investigation and hearing, which are incurred by the fund, whether paid or payable from the fund, and are a result of bringing the civil or administrative action against the defendant or respondent. In the same action, the defendant or respondent may claim from the department any costs and fees incurred in defending or responding to any action brought by the department in which the defendant or respondent prevails, upon a finding that the department's action was clearly frivolous or lacking in significant merit.
Ca. Pub. Res. Code § 14591.3