Tree Roots In The Septic System

Trees growing on your property are always searching for moisture and nutrients. Unfortunately, they might find them in your septic system. If there’s any seepage from the pipe feeding the tank or the discharge pipe leading to the drain field, tree roots are relentless in their quest to get inside the pipe.

Susan Day is an urban forestry expert at Virginia Tech. She says some trees are more prone to messing with your system than others.

"If you had a silver maple, which is an aggressively rooted tree, 10 feet from your drain line, you would have huge roots disrupting your drain line. I mean they actually move the pipes and so forth," says Day. "So you definitely don’t want large, aggressively rooted trees close to the drain field."

It’s impossible to predict how long it would take for roots to disrupt a septic leach field because every situation is different. Sewage backups in the home or a blockage in the septic tank can be signs of root intrusion.

However, Day says that doesn’t mean you can’t have trees near the leach field. 

"I would just plant them in between the drain lines so you have to know where they are so you’re not directly on top of one.  And I would use small statured trees that don’t normally get to more than say 20 feet in height and those are very small trees," she recommends. "And, I would always avoid any maples, any willows, any poplars, any of those species that are aggressive water lovers."

You could install a root barrier between your trees and the drain field. Geotextiles infused with a long-lasting herbicide have proven successful. They run the entire length of the field at a depth of around two-feet. Some roots might sneak under the barrier, but their pipe-clogging activity is greatly reduced.