§ 35.2120 Infiltration/Inflow.

(a) General. The applicant shall demonstrate to the Regional Administrator's satisfaction that each sewer system discharging into the proposed treatment works project is not or will not be subject to excessive infiltration/inflow. For combined sewers, inflow is not considered excessive in any event.

(b) Inflow. If the rainfall induced peak inflow rate results or will result in chronic operational problems during storm events, or the rainfall-induced total flow rate exceeds 275 gpcd during storm events, the applicant shall perform a study of the sewer system to determine the quantity of excessive inflow and to propose a rehabilitation program to eliminate the excessive inflow. All cases in which facilities are planned for the specific storage and/or treatment of inflow shall be subject to a cost-effectiveness analysis.