Tutorial - Septic System Basics

On-Site Wastewater Disposal

Briefly, a septic system is a method to safely treat household wastewater and dispose of the liquid into the ground.  Septic systems are also referred to as "on-site" wastewater disposal.  The opposite is "off-site" wastewater disposal such as municipal sewers and regional wastewater treatment facilities.  Septic systems are commonly used in rural and suburban areas where the housing density is lower and on-site disposal of wastewater is less likely to impact your neighbor and the environment.

Septic systems typically include the following components:

  • building sewer (pipeline) vented through roof
  • septic tank
  • distribution box (D-box)
  • a drain field, also known as a leaching facility or soil absorption system (SAS)

Figure 1 – Typical Septic System Components


There can be many variations on this basic layout.  In addition to the standard septic system components, your septic system may also include any of the following components:

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