RainfallPrecipitation in the form of water (usage includes snow). Induced 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.; is a particular form of infiltration which is similar to stormwater inflow. RII generally occurs during and immediately after rainfall events.
