Many water utilities have only a limited knowledge of the structural condition of their underground assests. In order to maintain optimum serviceability, it is increasingly important that utilities gain a better understanding of the current condition and performance of these buried assets. Regular inspection and condition assessment of pipelines can greatly assist utilities with developing robust and cost-effective operational maintenance programs, which will optimize capital expenditure whilst minimizing risk. The aim of the project was to conduct a state-of-the-art literature review of non-interruptive condition assessment inspection devices for large diameter transmission mains (greater than 12 inches). In addition, an expert panel workshop was to be held to review business needs and drivers, the performance of existing technologies, and future underground asset condition assessment research needs. Originally published by AwwaRF for its subscribers in 2004.