Infiltration(1) Penetration of freshwater or groundwater into the sewer system through cracks, defective joints in the pipeline, and holes, or through lateral connections, manholes or inspection chambers. (2) All extraneous waters (storm water and ground water) which enter the wastewater collection system through various sources including, among others, pipe defects, defective service connections, manhole covers, roof leaders, and foundation drains./Inflow; this is the sum of all the extraneous contributions to the collection system.