The bill establishes a presumption of compliance for entities covered under the state's industrial stormwater general permit, aiming to alleviate the burden of third-party litigation and enhance the safety of employees involved in stormwater management. It recognizes the unique challenges posed by stormwater discharges and the need for regulated entities to focus on environmental impact reduction rather than legal defenses. The legislation outlines specific conditions under which compliance with water quality standards is presumed, including full adherence to permit conditions and the implementation of approved best management practices.

Additionally, the bill stipulates that permit holders must notify the Department of Ecology within 30 days if they become aware of a potential violation of water quality standards, allowing for a resumption of the presumption of compliance once corrective actions are taken. It also addresses the health and safety concerns related to stormwater sampling at transportation facilities, stating that such sampling is not required until it can be conducted safely. The act is declared an emergency measure, taking effect immediately to support public health and safety.