The purpose of this chapter is to establish a fee system for state waste discharge and NPDES permits issued by the department pursuant to RCW 90.48.160, 90.48.162, or 90.48.260. RCW 90.48.465 authorizes the department to base fees on factors related to the complexity of permit issuance and compliance and to charge fees to fully recover, but not exceed the costs of the permit program based on expenses incurred in the issuance and comprehensive administration of state waste discharge and NPDES permits. Fee amounts contained in this chapter represent the department's true estimate of fee eligible permit program costs and reflect the department's commitment to fully recover all eligible expenses. The department shall continue to examine the feasibility of adopting, when applicable, alternative permit fee systems. Any alternative fee system, such as variable permit fees, shall ensure continued full recovery of eligible program costs and may be based on pollutant loading and toxicity and may be designed to encourage recycling and reduction of the quantity of pollutants.