This report brings together a body of information on the characteristics of the wastewater pipe network and the most common defects encountered. The technologies and methods in use by utilities to investigate these defects for the purposes of condition assessment are identified along with what are the perceived unmet needs.

A comprehensive review of the current state of the art of investigation technology is provided for both gravity and force mains. It also reviews data management and interrogation. A structured approach to investigation of gravity and pressure pipe is suggested.

Innovative investigation technologies and methods for gravity sewers are reviewed under five sections:

• Inspection of internal pipe surface       
• Inspection of pipe wall condition      
• Inspection of pipe wall condition and external condition      
• Inspection of external condition      
• Leak detection

Based on the identified unmet needs of the industry seven technologies for gravity pipe investigations and two for force main investigation, are identified as demonstrating potential for application to the wastewater industry.

Using a structured approach, each of the chosen technologies are reported in detail with information on details of the technology, its performance including field requirements, role of the operator, and costs. Where possible field monitoring was undertaken this is reported.