What does a drain field look like and how does it function in a septic system?

A drain field is a series of underground pipes or trenches filled with gravel that help distribute treated wastewater from a septic tank into the soil. The drain field looks like a flat area of grass or soil with small mounds or depressions where the pipes are located. The wastewater flows out of the septic tank into the drain field, where it is filtered and absorbed by the soil, allowing for natural treatment and disposal.