What kind of water enters the sewer system characterized by its source being from stormwater?

The correct answer refers to water that enters the sewer system as a direct result of precipitation events, specifically stormwater. This type of water is commonly referred to as inflow, which typically describes water that comes from outside the sewer system, effectively entering through defects and connections when there is an increase in water volume due to storms or heavy rainfall events.

Inflow is distinct from other types of water that might enter a sewer system for various reasons. It is important to clarify that while runoff is a term often used to describe water that is generated from precipitation and flows over land, it becomes part of the sewer system primarily through inflow mechanisms rather than being classified as runoff once it has entered the system.

On the other hand, infiltration refers to groundwater that seeps into a sewer system through cracks or holes in the pipes, posing different management challenges compared to water derived from storm events. Discharge, meanwhile, typically pertains to the outflow of wastewater or treated water leaving the system rather than water entering it.

Thus, the specific characteristic of the source being from stormwater is what makes inflow the appropriate term to describe this type of water entering the sewer system.