What term describes excess water entering the sewer system from groundwater or stormwater?

• A. Shock Load
• B. BOD
• C. Infiltration/Inflow
• D. Anaerobic Decomposition

Answer: (C)

Excess water entering the sewer system from groundwater or stormwater is described as infiltration/inflow. Infiltration is water that seeps into sewer pipes through cracks, joints, or other defects—usually groundwater or surface runoff finding its way in. Inflow is water that enters through direct connections or inlets, such as roof leader downspouts, sump pumps, yard drains, or storm sewers tied into the sanitary sewer. Together, these sources are called I/I and increase the volume in the sewer, stressing treatment plants, raising costs, and raising the risk of overflows during wet weather. The other terms don’t fit: BOD measures organic pollution, not water volume; a shock load is a sudden spike in contaminants or flow but not specifically groundwater or stormwater entry; anaerobic decomposition is a biological process that occurs in the absence of oxygen.