Many Nebraskans live in homes located in rural areas or small communities that do not have access to a public wastewater treatment system. Instead, they must rely on their own private systems for wastewater treatment and disposal. The most common on-site system used is a septic tank in combination with a traditional drainfield. A properly designed, installed, and maintained system should operate for 20 to 40 years or more, treating wastewater to minimize the negative impact on groundwater, surface water, and human health.
Bacteria partially decompose and liquefy the solids.
A system may have a drop box or distribution box between the septic tank and the drainfield to distribute effluent evenly between the drainfield trenches, described below. The effluent flows through the distribution pipes or tile sections where it moves through holes in the pipe or from the tile sections down through drainfield gravel or rock and into the soil. Water, carrying dissolved substances such as nitrate, slowly moves down to groundwater. Nebraska regulations require that there must be at least 4 feet between the bottom of the drainfield and groundwater or bedrock to minimize the movement of pathogens into groundwater. Figure 3 System Maintenance Proper maintenance of a septic tank and drainfield is critical to keep the system functioning properly.