Infiltration in sewerage networks is a well recognised problem. Its impact on the hydraulic capacity and performance of the sewerage infrastructure can be significant. The focus of research to date has mostly been on rehabilitation techniques and quantification of infiltration in relation to diurnal flow patterns.

UK Water and Sewerage Companies (WaSCs), as part of their strategic Development Statements / 25 year plans are looking to tackle key issues such as sewer flooding, energy (carbon emission) consumption and environmental issues (improving water way and river quality).  In many catchments across the UK, the presence of infiltration is impacting upon WaSCs ability to efficiently and effectively tackle these key issues.  As a result many of the water companies have been considering the economic case for dealing with infiltration.  In order to achieve this there is a need is to widen its study and investigate infiltration on a catchment-wide perspective.

A more complete understanding of the catchment situation will allow the true cost of infiltration; cost of energy through additional pumping station activity; cost caused related to the hydraulic performance of the sewerage infrastructure; impact and cost burden on sewage works’ processes; impact and cost caused by increased frequency of storm discharges at both the receiving treatment works and the sewerage system.