Unconventional, or aerobic systems, are best suited for clay, rocky soils found in many areas of the hill country. A conventional system can be used in areas where the soil conditions are better suited for soil absorbtion.

Conventional septic systems have traditionally been the most commonly used technology for treating wastwater. These systems use gravity to treat and distribute wastewater in the soil and typically contain two main parts: The Tank, and the Distribution Field.

The effluent flows through the gravel and enters the soil both below and to the side of the trench. Watch as this percolation process occurs in the figure above.

As the effluent moves through the soil, minute solids, bacteria, and nutrients are removed. This percolation process is a natural biological one that can safely treat the liquid before it reaches groundwater, if the system has been properly designed and maintained.