a)

1. 1) All grantees whose grant assistance is awarded after July 1, 1973 must demonstrate to the satisfaction of the Agency that each sewer system discharging into the treatment works project for which the grant offer is made is not or will not be subject to excessive infiltration/inflow. The determination whether excessive infiltration/inflow exists may take into account, in addition to flow and related data, other significant factors such as cost-effectiveness (including the cost of substantial treatment works construction delay), public health emergencies, the effects of plant bypassing or overloading, or relevant economic or environmental factors.

2. 2) The determination whether or not excessive infiltration/inflow exists will generally be accomplished through a sewer system evaluation consisting of:

   1. A) An infiltration/inflow analysis; and, if appropriate,
   2. B) A sewer system evaluation survey followed by rehabilitation of the sewer system to eliminate any excessive infiltration/inflow defined in the sewer system evaluation.

b) The infiltration/inflow analysis shall demonstrate the non-existence or possible existence of excessive infiltration/inflow in each sewer system tributary to the treatment works. The analysis should identify the presence, flow rate, and type of infiltration/inflow conditions which exist in the sewer systems. Information to be obtained and evaluated in the analysis should include, to the extent appropriate, the following:

1. 1) Estimated flow data at the treatment facility, all significant overflows and bypasses, and, if necessary, flows at key points within the sewer system.
2. 2) Relationship of existing population and industrial contribution to flows in the sewer system.
3. 3) Geographical and geological conditions which may affect the present and future flow rates or correction costs for the infiltration/inflow.
4. 4) A discussion of age, length, type, materials of construction and known physical condition of the sewer system.
5. 5) For determination of the possible existence of excessive infiltration/inflow, the analysis shall include an estimate of the cost of eliminating the infiltration/inflow conditions. These costs shall be compared with estimated total costs for transportation and treatment of the infiltration/inflow.
6. 6) If the infiltration/inflow analysis demonstrates the existence or possible existence of excessive infiltration/inflow, a detailed plan for a sewer system evaluation survey shall be included in the analysis. The plan shall outline the tasks to be performed in the survey and their estimated costs.
7. 7) The sewer system evaluation survey shall consist of a systematic examination of the sewer systems to determine the specific location, estimated flow rate, method of rehabilitation and cost of rehabilitation, method of rehabilitation and cost of rehabilitation versus cost of transportation and treatment for each defined source of infiltration/inflow.

8. 8) The results of the sewer system evaluation survey shall be summarized in a report. In addition, the report shall include:

   1. A) A justification for each sewer section cleaned and internally inspected.
   2. B) A proposed rehabilitation program for the sewer systems to eliminate all defined excessive infiltration/inflow.

   3. C) Exception

      In the event it is determined by the Agency that the treatment works would be regarded (in the absence of an acceptable program of correction) as being subject to excessive or possible excessive infiltration/inflow, grant assistance may be offered provided that the grantee establishes to the satisfaction of the Agency that the treatment works project for which grant application is made will not be significantly changed by any subsequent rehabilitation program or will be a component part of any rehabilitation system: Provided, That the grantee agrees to complete the sewer system evaluation and any resulting rehabilitation on an implementation schedule, which shall be inserted as a special condition in this grant agreement.