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Wednesday - July 16, 2014

From: Round Rock, TX
Region: Southwest
Topic: Trees
Title: Controlling Tree Roots in Sewer Lines
Answered by: Anne Van Nest


We had a leak with our underground pipes near the meter box - the pipes are at least a foot or more underground. My plumber poured table salt on the pipes to deter roots from a nearby tree from getting close to the pipes. Is this harmful to the tree and grass above ground?


There are references online about flushing salt (usually rock salt) regularly down the toilet to keep tree roots from growing into sewer lines. The rock salt is dissolved in hot water and poured down the toilet at night. This is usually recommended after situations when there have been sewer problems from tree roots and the roots have been removed by a plumbing professional. The frequency of using salt for this purpose and the amount of salt used cover a wide range and doesn’t appear to be very scientific or research-based. There are also other remedies suggested online such as using copper sulfate to clear tree roots from sewer lines.

Mr. Smarty Plants recommends using a commercial product specifically formulated for deterring roots from growing in sewer lines. This way there will be a specific instructions on when to use it, the quantity to use for a certain pipe diameter and length to the street. The product will have been tested and will be safe to use for the toilet and safe for the tree and lawn, and won’t have an effect on our future drinking water supply.


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