California Court of Appeal Rejects “Substantial Factor” Test for Regional Board to Issue a Cleanup and Abatement Order to a Responsible Person

After years of investigation, the San Diego Regional Water Quality Control Board (“Regional Board”) issued a cleanup and abatement order (“CAO”) to San Diego Gas & Electric Company (“SDG&E”) after finding that SDG&E caused or permitted waste to be discharged into the San Diego Bay, and thereby created, or threatened to create, pollution and nuisance conditions. SDG&E contested its designation as a “responsible person” under California Water Code section 13304 and petitioned for a writ of mandate to have the CAO vacated, arguing that the nuisance element of section 13304 must be construed in light of common law nuisance principles, and that the Regional Board had not demonstrated by substantial evidence that SDG&E’s actions were a substantial factor in creating, or threatening to create, a condition of pollution or nuisance. In furtherance of this argument, SDG&E relied on two cases, City of Modesto Redevelopment Agency v. Superior Court (2004) 119 Cal.App.4th 28 (Modesto I) and City of Modesto v. Dow Chemical Co. (2018) 19 Cal.App.5th...