FAQs - Details

Will trees and tree roots affect my system?

Roots from trees and shrubs can invade and plug sewer lines. Wastewater effluent is full of plant nutrients including nitrogen and phosphorus. Roots are attracted to leaking septic tanks and to absorption fields to obtain these nutrients. Roots can seriously damage septic tanks and distribution pipes resulting in significant repair costs. If you do have trees near your soil absorption field, they should be as far away as possible from the entry point of effluent to the drain field. Trees should be planted at least as far away as their estimated root spread at maturity. One way to estimate this is by the ultimate height of the mature tree. For example, a weeping cherry may be expected to grow about 25 feet tall, and should be planted a minimum of 25 feet away from the drain field. A mature oak might need to be 60 or 70 feet away. While trees do remove a significant amount of water from the area, avoid planting water-loving trees such as willow and poplar near the soil absorption field. If you are willing to risk some root intrusion, non-aggressive species can be placed near to the drain field (although closer than 10 feet is not recommended). Although the root spread of non-aggressive species trees may eventually encompass a portion of the drain field, the roots are not likely to cause serious damage to the distribution lines because the lines are surrounded by gravel. Still, the potential for damage to the system exists.