– by John Langard, NEWater Septic & Drainage Ltd. –
For newly constructed homes or older homes that have onsite sewage systems (septic systems), incorporating gardens and developing a landscape plan can be rewarding and challenging. There are different types of septic systems that result in different appearances in your yard, from an in-ground gravity system with one tank, to a raised sand mound with a treatment plant and up to 3 tanks. With some planning and a few basic recommendations, septic systems can blend in with the yard and become one with your overall landscape plan.
There are a few basic rules that you should follow when landscaping over a septic system drain field;
• Keep all irrigation lines 10 feet away.
• Avoid deep tilling (rototilling) over the drain field and septic tank areas.
• Avoid planting trees or shrubs with aggressive root systems like cedar, willow, maple, bamboo and aspen on or near your drain field and septic tank.
• Plant all trees and shrubs a minimum of 10 feet away from your drain field and septic tank.
• Avoid landscaping that changes the water drainage near your septic field.
Vegetation cover is important over a drain field to reduce soil erosion as well as excess moisture. Grass is often the first choice but a mixture of wildflowers and various grasses can create a low maintenance meadow appearance. Native plants such as sword ferns and Oregon grape are good choices when trying to create a natural, low maintenance theme.
If you are planning on planting flower gardens, annuals and perennials with shallow root systems are good choices. They can be planted directly over most drain fields and can blend in tank lids and raised beds to the overall landscape. Vegetable gardens can also thrive over a properly designed and functioning drain field, although it is not recommended over an older gravity system. Choose plants like tomatoes, cucumbers or peas and ensure that the vegetables are kept off the ground. Do not plant root vegetables over your septic field.
If you are planning on installing a new septic system in a mature lot, it may be a good time to think about any new landscape ideas that you may have. Talk to a landscape designer early and work with the septic system installer/designer to achieve the best possible landscape results. If you are planning on adding or altering any landscape or garden features or adding any retaining walls within 25 feet of your drain field, always check with your maintenance provider or designer before starting.
