COLUMBUS PRIVATE SOURCE INFILTRATION AND INFLOW IDENTIFICATION PILOT PROGRAM

The City of Columbus conducted a pilot study to assess private source inflow and infiltration (I/I) to the sanitary sewer from private laterals, sump pumps, foundation drains, downspouts, and miscellaneous exterior drains. The study included resident interviews, sewer televising, and water testing and concluded that foundation drains, defective laterals, and downspouts are the most common private sources. The study areas were found to have high rates of I/I, and private source I/I accounted for roughly 55% of the total I/I. The City has completed a detailed investigation of technologies to address sources of private I/I including sump pumps, lateral rehabilitation options and options to address storm drainage issues. Currently the City is in the process of implementing recommended corrective actions to reduce I/I from private sources and will use this information to decide if it will be cost effective to extend this program beyond the pilot study. This paper includes recommended testing procedures, repair technologies, and analysis techniques for addressing private sources of I/I.