Explanation of How a Septic System Works
A Septic tank system works on a simple design. It takes the wastewater from your home and allows the naturally occurring bacteria in the soil to treat the water.
All wastewater comes to a central drain, which runs from the house into the septic tank. A tank for a single-family residence is usually 1,000-gallon capacity. Septic tanks have one inlet and one outlet. The inlet is always higher than the outlet by design. The outlet determines the water level in the tank. In a tank that is operating properly the water level is always below the inlet. This allows the inlet pipe to remain empty between uses. A baffle divides the tank, leaving an opening at the bottom and half way up. The baffle holds floating solids on the inlet side of the tank. The outlet tee and filter also keep solids that may have passed the baffle from entering the field lines. This is the reason that it is so important to keep a septic tank pumped regularly. It prevents solids from building up in the tank and eventually destroying your field lines.
The field lines are a series of trenches in the yard that takes the water from the septic tank to return to the ground for final treatment. The septic tank catches and holds the solid waste, and the wastewater is leached into the field lines for treatment by the natural bacteria in the soil.