Tree Roots vs. Your Sewer Line

Photo of a sewer contractor working on a pipe by asterix0597/ lmysterious thing about tree roots growing into sewer lines is that it happens below ground, which means that you can't see it without a backhoe. It's a shame, isn't it? Because if something can make your toilet bubble up and your basement fill with sewage, you probably want to keep tabs on it.

What is a Sewer Lateral?

To understand how tree roots and sewer lines interact, you must first know what "a sewer lateral" is. A sewer lateral is the stretch of sewer pipe that extends from your foundation to the municipal sewer line under the street. Most municipalities will not repair or otherwise take responsibility for clogged or damaged sewer laterals. The Los Angeles Department of Public Works, for example, states that clearly on their website. If you live in L.A., hiring a plumber to deal with your sewer lateral is up to the homeowner. In most municipalities, homeowners are even responsible for maintaining and repairing the portion of the lateral that is under the street or sidewalk.

Locate the Problem

Which, of course, sort of stinks for homeowners (but it saves municipalities a lot of money). How can you even know if the problem you're experiencing involves the main sewer line or your own sewer lateral? OK. Manholes overflowing = overwhelmed municipal sewer lines. Sewage backed up into your basement = could be either the lateral or the main sewer line. If other houses on your street are also experiencing sewer problems, the issue is probably in the main sewer line. In that case, call the city. If your house is the only one with a sewer problem, call a bonded sewer contractor. Regular plumbers are not usually licensed to dig underneath the sidewalk or street. But bonded sewer contractors are. If the work is only on your property (not on the sidewalk or street), a licensed plumber can do the work.

What Causes the Problem?

Older sewer lateral pipes were often made of clay pipes, which crack more easily than newer plastic or metal sewer lateral pipes. Which brings us to tree roots: Tree roots are drawn to water. They can't help it. The universe was created in such a way that trees drink water through their roots. When a sewer lateral cracks, water leaks out of it. Because tree roots grow toward water sources, roots will actually enter the pipe through the crack, and grow inside the pipe.


Question: Should you just kill all the trees on your property? No, that would be horrible. Neighborhoods need trees to prevent urban heat island effect. If you and your neighbors don't have trees around your houses, your air conditioning bills will skyrocket. The answer to tree roots clogging up your lateral sewer line is to: A) auger the lateral sewer line regularly; and B) replace the cracked pipe.

If all of this sounds horrible and overwhelming, just know that augering your home sewer line is actually a DIY job, and is one that will make you feel extremely tough and competent. And replacing the cracked pipe helps your local economy. That, I am sure, does not take the sting out of having to pay a sewer contractor dig up your front yard and replace the pipe. But it's reality, and facing the facts is less stinky than a basement full of sewage.

Chaya Kurtz writes for

Updated May 10, 2018.

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