(1) For the protection of human health and the environment the department shall:

(a) Establish and provide for the comprehensive regulation of large on-site sewage systems including, but not limited to, system siting, design, construction, installation, operation, maintenance, and repair;

(b) Control and prevent pollution of streams, lakes, rivers, ponds, inland waters, salt waters, water courses, and other surface and underground waters of the state of Washington, except to the extent authorized by permits issued under this chapter;

(c) Issue annual operating permits for large on-site sewage systems based on the system's ability to function properly in compliance with the applicable comprehensive regulatory requirements; and

(d) Enforce the large on-site sewage system requirements.

(2) Large on-site sewage systems permitted by the department may not be used for treatment and disposal of industrial wastewater or combined sanitary sewer and stormwater systems.

(3) The work group convened under RCW 70A.110.080(4) to make recommendations to the appropriate committees of the legislature for the development of certification or licensing of maintenance specialists shall include recommendations for the development of certification or licensing of large on-site sewage system operators.