The terms "inflow" and "infiltration" both refer to clear water getting into sanitary sewer pipes. Inflow is clear water, generally rainwater, that enters the sanitary sewer pipe through direct connections, such as roof leaders, sump pumps, or foundation drains. Salem maintains a separate storm sewer system, which is intended to carry flow from clear water sources. Infiltration is groundwater or rain water that seeps into the joints of pipes, or through cracks in deteriorated pipes and manholes. A small amount of infiltration is expected in any sanitary sewer system. However, the goal is to eliminate large amounts of I and I into the sanitary sewer system.