567—91.1 (455B) Statutory authority. The authority for the Iowa department of natural resources to administer the clean water state revolving fund (CWSRF) to assist in the construction of wastewater treatment facilities and water pollution control works is provided in Iowa Code sections 455B.291 to 455B.299. The requirement to have selection criteria and a method for selecting projects or programs for loans is provided in 40 CFR Part 35.3150, July 1, 2002.