Infiltration refers to groundwater entering a sanitary sewer and diluting sewerage bound for treatment. Common points of groundwater infiltration include defective pipe joints and broken pipes. Inflow refers to water entering a sanitary sewer through an inappropriate connection such as a roof drain tied directly to a sewer main or lateral. Both infiltration and inflow result in the dilution of sewage and increased costs for treatment. During rain events, the sanitary sewer may overflow, creating a public health hazard.
MC Engineering has recently completed a comprehensive study of infiltration and inflow for the Clearlake Oaks County Water District.