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T he City of Westlake, OH, is located in the northeast- ern part of the state. The city is mostly residential with light industry and a population of 34,000. In 1992, the city implemented an inflow/infiltra- tion (I/I) program based on flooding problems. Since 1992, four areas have been investigated. Each area used similar rehabilitation techniques; however, certain lessons were learned from the testing to the construction phase. The four areas are King James Subdivision, Salem-Radcliffe Subdivision, Berkeley Estates, and Canterbury. All of the areas were built between the 1950s and the 1970s, with separate storm and sanitary sewers. Methodology Prior to any sewer rehabilitation or repairs, a sewer investiga- tion must be conducted to identify the types and locations of defects in the sewer system. These investigations utilize differ- ent testing techniques that focus on both public and private property. Both of these areas have different sewer compo- nents that are susceptible to deterioration and malfunction. For all of the projects undertaken by the city, either contractors or consultants conducted the testing as part of the sewer investigation. Testing for all of the project areas included some or all of the following testing methods: flow monitoring, mainline dye testing, residential dye testing, manhole inspection, and CCTV. Once the testing was complete, a detailed report was submit- ted to the city with recommendations for rehabilitation to the system based on the best engineering judgment at the time of the report. These reports included recommendations for main- line sewer lining, lateral lining, manhole sealing, and grouting. Results King James Subdivision The King James Subdivision was the first area to be investi- gated and rehabilitated by the city. The investigation for this area was conducted by a contractor, and data was provided to the city as data with no engineering recommendations. While engineering was completed internally, the contractor data report lacked the backup and details of the testing com- monly provided by a consultant. Testing in this area was focused on public property only. No flow monitoring was conducted for either post- or pre- rehabilitation monitoring. Testing consisted of mainline dye testing, which included adding dyed water to the storm sewer system and looking for leaks in the sanitary sewer, then using a CCTV camera to identify the leak and its location. From the testing results, a rehabilitation plan was developed and included the sealing of manholes and lining the sanitary sewer with a cured-in-place (CIP) sewer liner. The city revisited investigating the area since the flooding problems were not solved. The city felt that the problems wateronline.com ■ Water Online The Magazine Lessons Learned During Sewer Rehabilitation On Public And Private Property Four distinct sewer rehabilitation projects, each with its own set of challenges, offer guidance to others in the field. By Scott Belz, Bob Kelly, and Jim Smolik Case Study 36 Residential dye testing with GIS data Residential dye-testing manifold Sanitary lateral branch connection reinstatement