Grass is usually a good cover for a septic drainfield because it has shallow roots, protects the soil and allows air and moisture to move through it. Other shallow-rooted plants may be suitable if they fit local conditions and need little extra watering. Keep vegetable gardens off the drainfield and place trees and large shrubs well away from it; their roots can damage system components.
Check the system drawing before planning beds, and keep access lids and inspection points reachable. Avoid rototilling, deep digging, adding a thick layer of soil or changing the ground’s slope over the field. Ask a septic professional and a local nursery about suitable plants and spacing for the actual layout instead of relying on a universal distance. Our tank-location guide explains where to start looking for county system records.