Guidelines for Planting Your Garden Around a Septic Tank

by Ri Industries Ri Industries

Your septic tank is made up of a main outlet, a holding tank and a drainage field. The tank receives wastewater from your home plumbing system where it collects for a certain length of time until it exits the outlet and empties into the drainage field. There are certain plants that will fare better on or around your drainage field. So, what plants are good or bad for your wastewater treatment system? Here are some helpful “do’s” and “don’ts” for planting a septic tank friendly garden:

DO stay shallow

While being “shallow” is not considered a positive personality trait, it is very important that you stay shallow when it comes to planting your garden over a Ri-Industries septic system. A septic tank is generally installed about 0.6 to 0.9 meters underground, meaning you do not want the root systems of your small plants or shrubs to extend below this depth. The best plants to use near drainage fields are flowers, grasses, and small groundcovers that will not grow deep enough to disrupt the pipeline of your septic tank.

DON’T plant trees too close to your septic system

While Ri-Industries septic tanks are made from 40 MPa concrete, and the engineer-designed tanks are built to withstand anything, contractors generally believe that no tree is safe to plant too close to a septic system. This is because the root system provides a tree’s primary way of absorbing water, and those roots will extend toward the most abundant source of water in your yard. This means that if a tree is planted too close to a septic system, its roots will grow in the direction of the wet drainage field around it. Trees with smaller, less complex root systems are less of a risk to plant near the septic system, but especially try to avoid planting gum trees, cypress trees, maples, or willow trees anywhere near your Ri-Industries septic tank.

DO use shrubs that don’t require a lot of water, or are drought tolerant

Hydrophilic (water friendly) plants will grow deep into the ground, searching for moisture. The root system of water-loving shrubs can become entangled in the pipes of your septic system if planted too close to your drainage field, and cause problematic clogging. Try planting smaller shrubs whose root systems won’t cause a disturbance to your Ri-Industries septic pipes.

DON’T plant veggies near your septic tank

Fruits and vegetables should be planted at least three meters away from the drainage field of your septic tank to avoid bacterial contamination. This seems fairly simple, but it is also important to keep in mind as you plan out your planting!

DO plan ahead

Lay out the location of your shrubs before you start any digging. Plant shrubs near the end of septic tank lines where the soil is drier, or at least three meters away from the drainage field. You can also plant shrubs at the base or on side slopes of the septic mound, still keeping at least three meters away from the septic lines. Bushes planted downhill will absorb water and prevent erosion. Plants with shallow root systems can be planted right on the drainage field, while trees with deeper root systems should be planted at least 15 meters away.

Have any questions about how to design the perfect garden around your septic tank? Don’t hesitate to contact us with questions.