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.

The objectives are:
  • To develop a rational and practical set of inspection guidelines, i.e., best management practices, for ferrous force mains which can be implemented by wastewater utilities in their condition assessment programs.
  • To undertake a trial program with the researchers utility group to prove the guidelines are effective and practical.

The researchers aim is to provide operators of force mains in the wastewater industry with a workable set of guidelines which will allow them to undertake effective condition assessment of their ferrous mains using practical and economic investigation approaches. A soundly based condition assessment will enable an owner to make decisions on priorities for investigation, replacement and rehabilitation programs.

Available as an eBook only.


This report brings together a body of information on the characteristics of the wastewater force main network and the most common defects encountered. The technologies and methods used by utilities to inspect the force mains to identify and locate these defects are identified together with what are the perceived unmet needs. This report provides a comprehensive review of the current state-of-the-art in inspection technology for pressure pipelines. It also reviews the data management and processing and considers the application, effectiveness, and suitability of the technologies reviewed for use in force mains. The report also provides a risk-based failure evaluation.


Innovative inspection technologies and methods for force main inspection are reviewed under five categories: 1) external inspection of ferrous force mains, 2) internal inspection of ferrous force mains, 3) inspection of asbestos cement force mains, 4) inspection of prestressed concrete cylinder pipe force mains, 5) inspection of plastic force mains. The study includes 10 case studies of actual inspections undertaken on pressure mains using technologies reviewed in the report. It proposes a structured approach to force main investigation driven by information need and cost-effectiveness within a condition assessment and asset assessment program. It provides guidelines for developing and implementing force main inspection programs.