What is a leach field used for?

A leach field, also known as a drain field or leaching bed, is an integral part of a septic system designed to handle wastewater. Its primary function is to treat and distribute effluent in the soil, making option B the correct answer.

In a typical septic system, wastewater from the home flows into a septic tank, where solids settle to the bottom and bacteria begin the process of breaking down the waste. The liquid that remains, known as effluent, is then directed to the leach field. Here, the effluent is released into a series of perforated pipes buried in trenches filled with gravel or coarse sand. As the effluent seeps out of these pipes, it trickles into the surrounding soil.

The soil acts as a natural filter, providing treatment through physical, biological, and chemical processes. Microorganisms in the soil further break down contaminants, allowing the treated water to percolate into the groundwater safely. This process is essential for preventing groundwater contamination and maintaining public health.

The other options do not accurately describe the function of a leach field. Storing raw sewage, creating a tank for solid waste accumulation, and measuring water usage do not pertain to the leach field's role in treating and distributing wastewater.