Existing infrastructure and utilities in the ground have potential to be replaced or rehabilitated depending on the condition of that pipe. Utility owners are presented with various challenges of maintaining deteriorated water and wastewater pipelines while also prioritizing new water and wastewater projects to meet customer requirements. Some may view that deteriorating pipe in the ground as obsolete, however, there is potential value and savings associated with rehabilitation of that existing pipe compared to conventional dig and replace methods. The trenchless industry has advanced significantly in the past decade, providing a wide variety of installation methods to maximize the use of old pipe. Specifically, there are multiple structural solutions and semi-structural solutions to line or re-pipe existing water and wastewater transmission/distribution pipelines. In this session, we will discuss the AWWA structural classifications, fully structural sliplining methods of installation, semi-structural methods of installation, and how different technologies can be selected to maximize flow, life cycle, and overall operation of the pipeline. Case studies will be presented highlighting the value of a trenchless sliplining and modified slipling to rehabilitate existing pipe instead of open trench, dig and replace methods.