The Final Frontier for Inflow/Infiltration Removal: Going Where No One Has Gone Before

Many municipalities in the United States are faced with the problem wet weather flows and identifying the source of the problem. It has been shown in many municipalities that private sector inflow sources are major contributors to wet weather flows. The City of Lee's Summit, Missouri completed a comprehensive master plan for the development of its wastewater infrastructure to meet the short-term and long-term growth needs of the City. Lee's Summit is one of the most rapidly growing cities in the Missouri. The wastewater master plan quantified peak flows and evaluated the capacity of the collection system to convey these peak flows. The recommended plan to provide sewer service without backups in basements or sanitary sewer overflows included a combination of capacity enhancement and infiltration and inflow (I/I) removal.It was estimated that a major source of inflow was from the private sector. This paper presents the comprehensive private and public sector inspections that were performed to identify the sources of infiltration and inflow. Because inspection of private sewer laterals is not a common practice, the procedures and results are presented in detail to assist other agencies in their private sector investigation programs. The steps involved include education, identification and preparation of building address lists, training of field crews, customer notification and contact, inspection, and analysis.This paper also focuses on the quantification of the flows from the defects in both the public and private sectors, and how these defects relate to monitored flows. This information is helping the City prioritize the rehabilitation and repair efforts. In addition, the information will be used for setting future policy and approaches for private sector inspection and removal and for new building service line construction and inspection.