Can You Landscape Over a Septic Drain Field?

July 13 2020

Can You Landscape Over a Septic Drain Field?

We know that septic systems are installed underground in yards and that they are sensitive to pressure. At Septic Blue, we recommend that septic tank owners avoid parking their cars or driving over the septic tank and refrain from installing large structure on or around the septic tank. How about the septic drain field, however? Is it okay to landscape over a septic drain field? For the most part, yes you can landscape over a septic drain field but there are some things to consider. This article will go over some do’s and don’ts.

Quick Summary of How A Septic Drain Field Functions

The best way to understand the limitations of what work can be done over a septic drain field is to first get a grasp of how a septic drain field functions. After solid waste and wastewater leave the house and enter the septic tank, the liquid effluent is separated from the solids and flow into a series of perforated pipes. The wastewater then percolates through the soil in the drain field as soil microbes filter and clean the wastewater on the way down. These vital microbes use oxygen to function, so it is crucial that the soil allows for oxygen to reach the microbes; over-compacted soil threatens these microbes.

Acceptable Plants for The Drain Field

Growing the right kind of vegetation and plants on and around the drain field is actually advisable. Certain plants will prevent soil erosion and help the drain field function by soaking up excess moisture from the drain field. Perennials and grasses are best to grow around the drain field as their shallow roots are less likely to invade and damage the underground system. Bee balm, hollyhocks, and wild violets are perennial options that enjoy wet ground. If you insist on growing trees and shrubs, then choose shallow-rooted ones such as dogwood trees, holly shrubs, and azalea shrubs.

Plants to Avoid

On the other hand, there are trees and shrubs with roots that aggressively seek out sources of water, expanding far and wide for nutrients. Their violent roots know no boundaries and will not shy away from the pipes in the septic tank drain field. Weeping willows are an infamous example of trees with aggressive roots. Other similar trees and shrubs are Japanese willow shrubs, aspen trees, elm trees, and most maple trees. A general rule of thumb is to keep a tree at least as far away from the drain field as it is tall. So, if your birch tree is 60 feet tall, then you want to make sure it is at least 60 feet away from your drain field.

Growing Vegetables

The area over a drain field might seem like a tempting, open area to start a vegetable garden, but we advise against it. Though the microbes are tasked with cleansing the wastewater, the soil and water on the surface are much less likely to be cleansed to a level where it would be safely consumable. The risk of bacterial contamination is just not worth it. Septic Pumping in Fayetteville