Infiltration of groundwater into sewer lines has long plagued the operation of sewage collection and treatment facilities by greatly increasing the flows which must be accommodated. The cause of such infiltration is usually long-term deterioration of pipes and joints, but occasionally poor installation has resulted in new sewer lines running at full capacity even before any service connections were hooked up. Historically the only direct method to reduce the infiltration for small sewers was to dig up the lines and replace or repair them. This is very expensive and disruptive; consequently the solution most commonly adopted has been to bypass untreated sewage at peak flows or to increase collection system and treatment plant capacity to accommodate the higher wet weather flows.