How much of the first tank’s capacity should a two-compartment system typically hold?

In a two-compartment septic system, the first tank plays a critical role in the treatment process of wastewater. The recommended capacity for the first tank typically holds between one-half to two-thirds of the total tank capacity. This design allows for adequate settling of solids and effective anaerobic digestion, which is essential for reducing the amount of solids that enter the second compartment.

Having this amount of space ensures that there is enough retention time for the wastewater to undergo initial treatment before it moves to the second compartment, where further treatment occurs. Proper sizing of the first compartment is vital for maintaining the overall efficiency of the system and preventing overloading, which could lead to system failure or backup. Thus, the choice of one-half to two-thirds provides a balance between effective treatment, system longevity, and compliance with best practices in on-site sewage facility management.