Roots in the Sewer Line

TREE ROOTS VS. SEWER LINES - it's a classic match up and one that you would expect to have a predictable outcome. (The roots always win, right?) Well, not necessarily.

Roots will most certainly take advantage of any existing break, crack, or separation in a line of sewer pipe, but they will not initiate a break. Once a crack has developed, however - due to age deterioration, shifting ground, or other damage - the roots of nearby trees and shrubs will be attracted by the warmth and moisture in the line.

The flow of warm water inside a sewer lateral causes water vapor to escape to the cold soil surrounding the pipe. Tree roots are attracted to the water vapor leaving the pipe and they follow the vapor trail to the source of the moisture, which are usually cracks or loose joints in the pipe. Once the roots reach the crack or pipe joint, they will continue to grow through the opening to reach the nutrients and moisture inside the pipe - even in winter when you might think the trees would be dormant.


Problems Caused by Roots Inside Sewers
Once inside the pipe, roots will continue to grow, and if not disturbed or impeded by standing water, they may completely fill the pipe with hair-like root masses at each point of entry. The root mass then becomes matted with grease, tissue paper, and other debris that would normally flow freely through the line. The first signs of a slow flowing drainage system are gurgling noises from toilet bowls and wet areas around floor drains. A complete blockage will almost certainly occur if nothing is done to remove the roots and partial blockage.

As roots continue to grow inside the pipe, they expand and exert considerable pressure at the crack or joint where they entered the pipe. The force exerted can break the pipe and may result in total collapse of the pipe, at which point the affected section will require replacement.

Deteriorated sewer laterals leak raw sewage into the ground, which can create a health hazard. Groundwater and rain also seep into the sewer system overloading it and the wastewater treatment facility beyond their capacity. The resulting backups and overflows lead to the discharge of untreated sewage into the Bay and the creeks.


What You Can Do to Control Roots in the Sewer Lateral
Once you suspect roots in your line (inspection with a video camera can confirm this), it is possible to clear them and, with periodic maintenance, keep them clear. Here at Boden Plumbing, we clear roots from sewer lines using what we call a "scorpion cutter" that effectively scours the line of any roots and build up. We then follow that up with the application of a foaming herbicide to retard regrowth. Continue treatment every 9 to 12 months with the herbicide and that should keep the roots from growing back.

A longer term solution is to follow up the scorpion cleaning with a reline of the sewer pipe. This can be done as a spot repair if just one section of the line is compromised or along the whole length of the pipe, but it needs to be done while the pipe still retains its form. Once a section or length of pipe has collapsed, it will need to be dug up to effect a repair.

There's no need to remove a tree solely because of roots in lines. The best defense against having tree roots in lines is to make sure that your lines are in good condition and that they're not cracked. So inspect the line if you suspect a problem, and clear those roots if you find them. If you know the condition of your sewer line you can reline before the pipe collapses!

For more info, check out these resources:

:: NuFlow technology
:: Boden Plumbing trenchless services
:: About RootX