The City of Alexandria is going to be evaluating the sanitary sewer system in your neighborhood to find sources of water infiltration and inflow. During wet weather, infiltration and inflow can increase the flow to sanitary sewers to the point of overload. When this occurs, the excess flow can overflow and release pollutants into our waterways and damage private property by creating back-ups into basements. Infiltration and inflow are terms that describe groundwater and storm water that enter the sanitary sewers.
Infiltration is groundwater that enters sanitary sewers through leaks in pipes.
Inflow is storm water that is directed to the sanitary sewers through connections such as roof downspouts, driveway drains and groundwater sump pumps. The sanitary sewers are meant to carry only wastewater, which comes from fixtures such as sinks, toilets, bathtubs and washers. The City's sanitary sewers convey wastewater to the Alexandria Sanitation Authority treatment facility. When infiltration and inflow enter the sanitary sewer, they take up pipe space that is required for the wastewater. The infiltration and inflow can cause sewer backups and overflows into the environment during wet weather.