Where nature and the city meet

The City of Indianapolis constructed the Eagle Creek Reservoir (ECR), prior to and through 1967. The primary purpose for its development was flood control on Eagle Creek.

How a Septic System Works

A septic system is an on-site treatment system designed to handle household wastewater.  The system consists of three main components – a septic tank, a distribution box, and a soil absorption system (leach field, finger system, or absorption field). 

Septic Tank

Distribution Box Absorption Field


Wastewater from toilets, sinks, showers, and other drains flow from the household sewer drain to an underground septic tank.  Once in the septic tank, the waste separates.  Solids settle on the bottom of the tank forming the sludge layer.  Grease and fatty solids float to the top forming a scum layer.  The remaining liquid remains in the middle and forms the liquid layer.

Once separated, the liquid layer, or effluent, flows from the septic tank into the absorption field by way of the distribution box.  In the absorption field, the effluent moves through the pipes and seeps into the surrounding soil.  The soil filters out suspended solids and organic matter.  Bacteria in the soil then decompose harmful microorganisms and other organic components.  Clay particles trap viruses and eventually die.  Treated effluent continues downward as it percolates through the layers of soil.