Which term refers to water that enters the sewer system due to rainfall, snowmelt, or other surface runoff?

Which term refers to water that enters the sewer system due to rainfall, snowmelt, or other surface runoff?

• A. Infiltration
• B. Inflow
• C. Effluent
• D. Surcharge

Answer: (B)

Inflow is water that enters the sewer system from outside due to weather events like rainfall, snowmelt, or other surface runoff. This water comes from surface sources such as storm drains, yard drains, or downspouts that discharge into the sewer, and it increases the flow in the sewer during wet weather. Infiltration, by contrast, is groundwater seeping into the sewer through cracks and joints in the pipes—water that enters through the pipe walls rather than from surface runoff. Effluent is the treated wastewater discharged from a treatment plant, and surcharge refers to a condition where sewer flow or pressure becomes elevated, potentially causing backups. So the term described is inflow.

Inflow is water that enters the sewer system from outside due to weather events like rainfall, snowmelt, or other surface runoff. This water comes from surface sources such as storm drains, yard drains, or downspouts that discharge into the sewer, and it increases the flow in the sewer during wet weather. Infiltration, by contrast, is groundwater seeping into the sewer through cracks and joints in the pipes—water that enters through the pipe walls rather than from surface runoff. Effluent is the treated wastewater discharged from a treatment plant, and surcharge refers to a condition where sewer flow or pressure becomes elevated, potentially causing backups. So the term described is inflow.