(1) The following programs shall be eligible for state matching grants in an amount not to exceed fifty percent of the total eligible cost of a project as determined by the department: The marina pumpout grants program, the water supply plant residual waste treatment works grants program, the lake restoration grants program, the state construction grants program and the agricultural pollution grants program. The department may authorize a matching grant less than fifty percent of the total eligible cost of a project in those cases where it would be in the public interest, or where federal matching funds are available and it would be in the public interest to secure a local matching portion.

(2) The federal construction grants program may be eligible for state matching grants in an amount not to exceed fifteen percent of the total eligible cost of a project as determined by the department except as provided in WAC 173-255-050(1).