Tree Roots in Sewer Lines: How They Get In and What to Do

How roots get into a sewer line

Roots are how a tree gets water and nutrients, and UGA Extension points out that sewer and septic lines offer a constant supply of both (UGA Extension). Traverse City, Michigan's sewer department explains the mechanism. Warm water flowing through a sewer pipe lets vapor escape into the cooler soil around it; roots follow that vapor to cracks or loose joints and grow inside, where they thrive in the moist, nutrient-rich space above the water. This continues in winter, and because roots need oxygen, they don't grow in pipes that run full (City of Traverse City).

Once inside, fine roots mat together with grease, tissue and other debris. As they grow, they push on the crack or joint where they entered and can eventually break the pipe or make it collapse. Pipe material matters: Traverse City says clay tile pipe was easily penetrated by roots, while PVC resists them better because it has fewer, tighter joints. Old sewer pipe materials explains how to tell what you have.

Signs roots may be the problem

UGA Extension links root intrusion to slow drainage, blockages and backups into the house (UGA Extension). Traverse City's sewer department adds two early signs: gurgling from toilets and wet spots around floor drains after a load of laundry (City of Traverse City). The same signs can point to other main-line problems, so compare them with main sewer line clog signs.

A camera inspection is the most direct way to confirm roots, see where they're entering and judge whether the pipe is cracked, separated or broken. That finding decides whether cleaning alone makes sense.

Clearing roots: cutting and jetting

The common tools are augers, root saws and high-pressure jetters (City of Traverse City). They reopen the pipe but don't close the crack or joint the roots came through, which is why Traverse City recommends regular cleaning and keeping the line structurally sound. Drain cleaning methods explained compares the equipment.

Outdoor root cutting also carries a less obvious risk. Atlanta Gas Light warns that a gas line installed by boring can pass straight through a sewer pipe, a condition called a cross bore, and that running a rotary cutter without first locating utilities and inspecting the line with a camera is discouraged and could be dangerous. It tells customers to call 811 before digging to repair a blockage, and says that even without digging, the safest approach to a blockage out in the yard is to have underground lines located through 811 first (Atlanta Gas Light).

If a gas line may have been hit, or you smell a rotten-egg odor that could be natural gas, treat it as a gas leak. Atlanta Gas Light says to leave the area at once, avoid anything that could make a spark, including phones and light switches, and not try to find or stop the leak yourself. Call 911 or your gas utility once you're out of the area and safe, and stay away until the gas utility or emergency crews say it's safe to return.

Root-control chemicals are pesticides

Root killers made for sewer lines are pesticides registered with EPA, and their labels are legally binding. The copper sulfate product label described below states that using it in any way inconsistent with its labeling violates federal law (copper sulfate label).

Some products are off-limits to homeowners. The EPA-accepted label for one foaming product containing metam-sodium and dichlobenil classifies it as a restricted use pesticide because of acute inhalation and skin toxicity, for sale to and use only by certified applicators or people under their direct supervision. Its precautions warn that foam can come up through building drains, require drains at risk of backup to be plugged, and tell building occupants to leave if they notice the chemical's sulfur-like odor, then open windows and ventilate (metam-sodium foam label).

Products sold to consumers have limits, too. One copper sulfate root killer's label carries the signal word DANGER, calls for goggles or a face shield, says never to pour it into sinks or tub drains, sets a minimum of 6 months between treatments, and says a completely blocked line must first be opened with a snake or sewer rod (copper sulfate label). In other words, chemicals don't clear a full stoppage.

If you hire a company to apply a root treatment, ask about its licenses. The Georgia Department of Agriculture says applying any pesticide, general use or restricted use, to another person's property for a fee requires both a commercial applicator license and a pesticide contractor license (Georgia Department of Agriculture). Before using any root chemical yourself, read the whole label and check with your sewer provider. See a doctor if you feel ill after exposure, and follow the label's first-aid directions.

Fixing the entry points

Cutting treats the symptom; fixing the damaged pipe treats the cause. Traverse City notes that pipes with severe root intrusion or structural damage will need replacement (City of Traverse City). Lining is an option in some cases, but the 2024 International Plumbing Code doesn't allow relining where the camera shows complete separations, such as those from tree root invasion; those sections must be dug up and repaired with new pipe and fittings (2024 IPC, Section 717.5). Sewer line repair options compares spot repair, lining, pipe bursting and replacement.

Planting smart, and trees that aren't yours

UGA Extension's general recommendation is to keep trees and plants with aggressive root systems away from septic and sewer lines, and to find out where your lines run before you plant (UGA Extension). Call 811 before you dig a planting hole.

If the tree in question stands between the sidewalk and the street or elsewhere on public land, don't cut, poison or remove it on your own. In Savannah, for example, the Park and Tree department manages public trees and rights-of-way, and residents request service for a public tree by phone or through the city's online request form (City of Savannah). Other Georgia cities and counties have their own rules, so ask yours first. Who pays for root damage in a section of line under public land depends on your sewer provider; see who is responsible for the sewer line in Georgia.

Next step

Get a camera inspection that shows where roots are entering and whether the pipe is cracked, separated or broken, then decide between scheduled cleaning and a permanent repair. This guide is general information, not legal or medical advice; a licensed plumber, your sewer provider and your city's tree staff can advise on your situation.