How to Stop Tree Roots From Plugging Sewer Lines

Solutions for invasive tree roots

Keep invasive tree roots from plugging your sewer line by boring them out with an rented auger, cutting the trees or calling in pros. The pros will bore the line open for you, treat the roots with poison, replace the old pipe or reline the old pipe.

By the DIY experts of The Family Handyman Magazine

TIME

One day

COMPLEXITY

Complex

COST

$100 - $500

What to do if tree roots clog your sewer pipe

If you live a wooded lot and have problems with tree roots invading your sewer system and clogging it up, don't assume you have to cut the trees down! As you can see from the photo, the tree roots work their way through cracks or joints in older sewer lines made of clay tile, cast iron or an asphalt composite style called “orangeberg” piping. The roots are seeking that nutrient rich soup you're sending down the drains and toilets (there's no accounting for taste). Clay and cast iron are rarely used anymore because of those loose-fitting joints that tree roots can penetrate. These materials are also heavy, hard to work with, expensive, brittle and prone to breakage. Nowadays nearly all sewer lines are made of plastic pipe—it's cheap, tough and lightweight, and the joints are impervious to tree roots.

You've got three options, none ideal: Continue reaming the lines periodically, cut down the trees, or call in the pros. Larger sewer-cleaning companies will ream out the line or actually send a mini video camera inside the pipe to determine exactly what the problem is. They'll find out if the line is crushed, cracked, or sloped improperly, or if tree roots are worming their way through cracks or loose joints. Then they'll recommend a course of action, which could be:

  • Digging up the old line and replacing it with plastic.
  • Treating the line with a poison formulated to kill nearby tree roots. That way it'll take much longer for new roots to cause problems. These poisons are designed to kill just problem roots—not the whole tree.
  • Sealing the line by lining the existing pipe with an internal plastic fabric and cement. Companies have been doing this for years on larger lines and are just beginning to line residential ones. Chances of finding a local company that does residential sewer lining are slim, but it doesn't hurt to ask.
  • One of our editors has the same recurring problem as you. He got tired of the $100 service call every year (always on a Sunday while entertaining friends), so he bought his own $400 power auger and cleans out the lines himself. You can also rent one.

Roots in a Sewer Line

Roots commonly enter old clay tile sewer lines at open joints or where the tile has been cracked or crushed.

Close-up of sewer line Roots enter clay sewer lines at joints
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Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

  • Pipe wrench

You might need a power auger (rental).