Private Property Inflow Removal – A Tale of Two Cities Lansing and Port Huron, Michigan

This paper discusses two projects related to removal of rainwater inflow sources from sanitary sewer systems on private property. The first is private property inflow removal associated with Combined Sewer Overflow (CSO) sewer separation programs in Lansing and Port Huron, Michigan. Private property inflow removal is required to help prevent basement flooding and other sanitary sewer overflows (SSOs) in the sewer separation areas. To date, with over 1,200 acres separated since 1992, the Lansing program has achieved voluntary removal of over 88% of identified sources, leaving 97% of all properties with no inflow source remaining. The area remaining to be separated is 5,500 acres.The City of Port Huron, Michigan, began a private property inflow removal program in 1999. This program was initiated after the sewer separation project had begun. To date, the City has completed or has under construction projects to separate 513 acres. The private property inspections have been performed primarily on residential properties in the service areas. Of 1,412 residential properties inspected, 63 properties have been identified with inflow sources.Keys to success for these programs include: property owner understanding, city identification of inflow sources, free advice and site visits, tracking and follow-up, flexibility on removal method, and Ordinances to help enforce inflow removal on all private properties.The second project is a study / investigation of inflow source inspections on public and private property in the Tecumseh River Pump Station area of Lansing. This area underwent a Sanitary Sewer System Evaluation in the early 1980s, but has continued to experience infrequent basement flooding during extended wet weather events. Inspection of all 1,975 occupied private parcels and all public manholes and catch basins in 1998-99 revealed significant inflow remaining and/or reconnected. The pump station serving the Tecumseh area was also found to be operating at less than design capacity.