(1) The agency may require an owner or operator to return any cost overpayment made by the program. Overpayments may occur if:

(a) Another party, such as an insurer, has paid costs prior to payments from the program; or

(b) The agency discovers an accidental overpayment has been made to an owner or operator for any reason.

(2) If a cost overpayment is not paid upon demand, the agency may pursue the following actions:

(a) Collections. The agency may request cost recovery with a debt collection agency.

(b) Lien filing. The agency may seek cost recovery of remedial action costs by filing a lien on the petroleum underground storage tank facility as authorized under RCW 70A.545.070.

(c) Civil action. The agency may request the attorney general office to commence a civil action against the owner or operator in superior court to recover costs and the agency's administrative and legal expenses to pursue recovery.