Sizes vary based on conditions, local regulations, and septic tank size: A 1,500-gallon tank can require a drainfield of 800 to 2,500 square feet. Other terms used for a drainfield: leach field ...

It’s also important to understand where the tank and the septic drainfield is located before digging or trenching for any landscape or building project, to avoid damaging any of the leach lines.