We have 2 trees growing in the same area of our house front yard as the sewer line. As shown in the picture below, one tree is about 5ft away from the line, and the other, about 20ft away. I assume that the water supply line runs next to the sewer line as well. We're concerned about the tree roots getting into the water/sewer lines in the future. What's the most cost-effective preventive measure (aside from cutting the trees down) that will work? My research has led me to root barriers, but wondering if installing them on either sides of the lines is the best way in this case. If so, are there barriers made specifically for water/sewer lines?

Our front yard trees vs. sewer line

  • What material is the sewer line made of?
    – JimmyJames
    Mar 2, 2020 at 17:14
  • I don't know. The house is 18yrs old. Does that mean it's likely plastic? Is it a safe DIY to carefully dig a small hole to find out to be sure? Thanks. Mar 2, 2020 at 21:07
  • 2
    18 years the chances that your drain lines are plastic is 99.99%. So as in my answer you have plastic and only will have to worry when the roots get large and move things around like the pipes and sidewalks.
    – Ed Beal
    Mar 2, 2020 at 21:23
  • Thanks. We already see the large tree slightly lifting the drive way slabs next to it where the silver car is parked in the pic. (We're not seeing the small tree having any large roots.) Would you estimate the chances of the large tree moving pipes from 20ft away to be extremely low? Mar 2, 2020 at 23:07
  • 1
    I wouldn't worry. Most of the problems with roots come from them finding their way into the joints in old cast-iron pipes as explained in Ed Beal's answer. PVC pipes (which is what you likely have) are chemically bonded together at the joints. In order for roots to get in properly installed PVC, the pipe would need to fail in a much more catastrophic way. No need to dig a hole, just look at the cleanout, it's going to be the same material as the line.
    – JimmyJames
    Mar 3, 2020 at 14:48

1 Answer 1


The best way to prevent root problems is to replace old leaking cast or concrete pipe with plastic. Once glued there is no need to worry about plastic even when roots grow and buckle plastic (decades long process) plastic moves doesn’t usually break like concrete or cast that has many brittle joints that leak and draw the roots. If you have replaced a section and want to protect a fernco connector or “no hub” I have been told to pack the area with rock salt as the roots won’t like the high salt content, but the salt will dissolve and eventually leave a low point. Supply lines are better sealed than old drain lines and over the years as a tree gets large enough it may affect the lines so the only fool proof method is to not put your tree close.

Your Answer

By clicking “Post Your Answer”, you agree to our terms of service and acknowledge you have read our privacy policy.

Not the answer you're looking for? Browse other questions tagged or ask your own question.