Infiltration problems are common to many communities throughout the United States. Designing collection systems which can adequately collect and transport sanitary sewage depends not only on the quantity of sanitary sewage to be handled but also upon the quantity of storm and ground water infiltration which must be anticipated. The report is confined to the sealing of sanitary sewage collection systems. It is the intent of the study and report to describe the use of an external application of asphaltic sealants in several different localities. By actually sealing leaking lines in areas of differing soil characteristics and in systems which employ differing pipe and jointing methods, it has been possible to include a sufficient variety of conditions to approximate conditions common to many communities in the United States.