This study shows that sewer Electro-Scanning is able to pinpoint pipe defects that are large sources of collection system infiltration.  These defects were not located using other investigation methods.
The City of Redding has used flow monitoring, television inspection, joint air pressure testing and smoke testing for infiltration assessment and location for more than 20 years. Despite repairing all detected leaks, the collection system wet weather flows were consistently 300% greater than dry weather flows.

A pilot study, Electro-Scanning 7.6 km (25,000 ft) of main line sewers was instigated to pinpoint the sources of the infiltration in a sub-basin that had particularly high peak wet weather flows of 1.7 megalitre (450,000 gallons) per day.

This paper describes how the Electro-Scan data was used to select twelve locations for spot repair. Photographs of some of the defects found when the pipe was exposed are included. The locations were accurate and large defects were found and repaired. After the repairs the peak wet weather flow decreased to 0.9 megalitre (250,000 gallons) per day.

This paper also discusses how the straightforward Electro-Scan testing was integrated into the regular jet cleaning maintenance operations.