How to Keep Tree Roots from Growing Into Sewer Lines

As far as a tree is concerned, a sewer line is the jackpot. The sewers carry water and nutrients no matter the time of year. So, trees tend to grow towards them. The problem is that some tree roots are quite strong, while some sewer lines are quite weak.

Trees can rip holes in sewer lines, or collapse them completely. These sewer leaks are expensive and frustrating to fix, in part because the sewer line will be intertwined with tough tree roots. How do you prevent tree roots from causing this problem in the first place?

1. Choose the Right Tree

The best cure is prevention. This won’t be an option for you if you already have a troublesome tree, unless you’d like to cut down the problem tree and plant a new one in it’s place. Plus, this may not be the best solution for those in rural areas in thick forests, where one tree or another is eventually going to bother your pipes.

However if you’re choosing a tree to plant on your property near your sewer lines, there is a strategy. Trees should be planted at least ten feet away from a sewer line, but much depends on your type of tree. Trees that are made for wet conditions and that grow quickly, like willows, poplar, sycamore and cottonwoods, will do more damage to sewer lines and should be planted at least thirty feet away from sewer lines.

There are slower, gentler trees you can choose to plant closer to sewer pipes, including oaks and Japanese maples. Also consider short trees or shrubs who roots don’t grow as far, including apple trees, spruce, dogwood, and lilac.

2. Replace Your Sewer Lines

Some types can stand up to tough tree roots without crumbling. If you’re in an older neighborhood, especially in a rural area, you may have older, much more vulnerable sewer lines, including those made from clay or a kind of wood pipe called Orangeburg pipe.

If your old sewer lines are cast iron, don’t replace them—they’re quite strong. In fact, if your sewer line is in danger from tree roots you should consider cast iron over a modern PVC plastic pipe.

3. Cut the Roots

Even if you have tough pipes, you may need to cut back tree roots routinely so that your plumber can get to your sewer line easily in the event of a leak. Have your plumber mark out where the pipe is, and have your landscaper dig beside the line and use a power tool to cut down the roots.

So long as the tree is healthy and mature, this process will not damage it. In fact, it won’t keep it at bay for long. You’ll need to cut the roots of problem trees once per year.

4. Apply Chemicals

Certain chemicals will discourage tree roots from growing. You should get your landscaper’s advice about which chemicals to apply, and have them apply the chemical while cutting out the roots. Or, you can purchase sleeves for your pipes, treat the outside of the sleeves with the same chemical, and have your plumber install the sleeves on your sewer lines.

If you know you have a problem tree near your sewer roots, it’s important to look into the problem yearly. A collapsed sewer line is a very serious problem that can be costly to fix.