When it comes to maintaining a septic tank, most people think about regular servicing and being mindful of what goes down the drain. But did you know that your landscaping for septic tank gardens can also have a significant impact on the health of your septic system?

The types of plants you grow, where you plant them, and how you maintain your garden can either help or harm your septic system. 

Landscaping around your septic system doesn’t have to be complicated—it’s all about choosing the right plants and being mindful of where you put them.

By following these dos and don’ts specific to Western Australia, always remember that the right landscaping can extend the life of your septic system and prevent expensive repairs, saving you time, money, and stress in the long run.

Choose Shallow-Rooted Plants

When selecting plants to grow near your septic tank, opt for those with shallow root systems. Shallow-rooted plants are less likely to penetrate septic lines and cause damage. Grass, ground covers, and small perennial flowers are excellent choices, as they add beauty while keeping the ground stabilised without risking damage to the tank or pipes.

In Western Australia, native grasses like Kangaroo Grass (Themeda triandra) or Wallaby Grass (Rytidosperma spp.) are great options. You can also consider using small perennial flowers such as Everlasting Daisies (Rhodanthe chlorocephala) or Billy Buttons (Craspedia globosa), which add colour while being septic-safe.

Use Native Plants

Native plants are a fantastic option because they are well adapted to the Western Australian environment. This means they require less water, less fertiliser, and are generally lower maintenance—reducing the risk of overwatering, which can disrupt septic system efficiency. Additionally, native plants have root systems that work well in the soil conditions around septic tanks.

Consider using species such as Kangaroo Paw (Anigozanthos spp.), Geraldton Wax (Chamelaucium uncinatum), and Blue Leschenaultia (Lechenaultia biloba). These plants are hardy, drought-tolerant, and have non-invasive roots.

Create a Low-Maintenance Garden

Planting low-maintenance ground covers like Creeping Boobialla (Myoporum parvifolium) or Native Violet (Viola hederacea) can protect the area above your septic tank from erosion. It also reduces the need to dig or cultivate near the septic field, minimising the risk of accidentally disturbing or damaging your septic system.

Maintain Proper Distance for Trees and Shrubs

If you wish to plant trees or shrubs, make sure to plant them well away from your septic tank and drain field. Trees and shrubs generally have aggressive root systems that seek out moisture—which means they could infiltrate your septic pipes. As a rule of thumb, any tree or shrub should be planted as far away as its anticipated mature height. For instance, a tree that will grow to 10 metres should be planted at least 10 metres away from your septic system.

In Western Australia, avoid planting larger native species like Bottlebrush (Callistemon spp.) or Paperbark (Melaleuca spp.) near your septic system, as these tend to have aggressive roots.

Use Raised Beds and Light Mulch

If you want to add more variety to your landscaping, consider using raised beds. Raised beds can help create an aesthetic feature while ensuring that the roots of plants don’t reach deep into the septic system. Just be sure that the raised beds are lightweight and positioned strategically. Light mulching around small plants can also help retain moisture without adding too much weight or stress to the system.

Don’t Plant Large Trees Near the Septic System

Avoid planting trees such as Willows, Jacarandas, or Eucalypts near your septic system. These species have aggressive roots that can seek out the moisture and nutrients from your septic tank and drain field. The roots can infiltrate and damage pipes, leading to costly repairs and disruptions.

Don’t Install Hard Landscaping Features

Hard landscaping elements such as patios, decks, paved pathways, or retaining walls should not be placed near the septic tank or drain field. These features add unnecessary weight, compressing the soil and potentially damaging the tank or lines. Additionally, they make it difficult to access the septic system for maintenance or emergency repairs.

Don’t Plant Vegetable Gardens Over the Drain Field

While it may be tempting to utilise all available space in your garden, avoid planting vegetables or anything edible over your septic drain field. The drain field is designed to filter wastewater, and the vegetables may be contaminated by harmful bacteria or chemicals from the wastewater. It’s safer to stick to ornamental plants.

Don’t Overwater the Area

Too much water can put stress on your septic system, as it can lead to a waterlogged drain field. When landscaping near the septic area, it’s essential to avoid overwatering. Excess water can reduce the soil’s ability to treat waste properly, potentially causing backups or slowdowns in your system.

Don’t Dig or Cultivate Around the Septic Area

Refrain from using heavy equipment or tilling the area above your septic tank and drain field. Digging into the ground may damage pipes or disturb the delicate balance of your drain field, leading to system inefficiencies or even a complete system failure.

Grass Lawn with Native Flowers

A simple grass lawn is one of the safest and most effective choices for covering the area above your septic system. Adding native wildflowers to this space is also a great way to add beauty while maintaining the health of the system. In Western Australia, varieties like Everlasting Daisies (Rhodanthe chlorocephala), Kangaroo Paw (Anigozanthos spp.), and Blue Leschenaultia (Lechenaultia biloba) are excellent choices.

Wildflower Meadow

A wildflower meadow can be an attractive, low-maintenance landscaping choice for your septic area. Not only does it add beautiful colour and support local pollinators, but it also keeps the soil stabilised and ensures minimal disturbance to the septic system. Use a mix of native species like Pink Everlasting (Schoenia filifolia) and Golden Everlasting (Xerochrysum bracteatum).

Raised Herb Garden

If you want to add a touch of greenery without risking damage to your septic system, consider planting a raised herb garden a safe distance away from the septic tank. Herbs like oregano, thyme, and basil thrive in raised beds and can add both beauty and functionality to your garden.

Shrub-free Border Gardens

Use light mulching and plant low-growing, non-woody perennials around the septic tank as borders. This can help mark the location of the septic system, while still ensuring that the area is decorated and visually appealing without any risk of damage from deep roots.