How to Use Rock Salt for Tree Root Problems

Updated February 21, 2017

Rock salt is simply table salt (NaCl) in rock form instead of granules. It can be used as a cost-effective home remedy to clear your pipes of tree root infestation. Tree roots are particularly notorious for growing into sewage pipes, causing draining issues. According to the University of Illinois Extension, you can use rock salt for tree root problems because of two ways in which salt affects trees. First, like a salt shaker that becomes clogged, salt cakes when combined with light moisture. Salt will clog tree roots and soak up the water they need for survival by creating a drought-like environment. Also, when rock salt is dissolved in water, the ions separate and chloride ions are absorbed by the tree roots, causing toxic build-up and obstruction of necessary nutrients.

Measure out 2 cups of rock salt. Pour the 2 cups of rock salt down one toilet in your home. Use this method first to attempt to block water absorption from tree roots that are interfering with areas within or near your home's pipe system. Since trees grow in the direction of what they need to survive (water and nutrients), it is common to find tree roots growing into sewer lines, which can disrupt your plumbing as well as cause issues with your foundation.

Consider a liquid solution as an alternative to dry salt if you are experiencing severe water interruption or basement flooding. Measure out 2 cups of rock salt and place in a medium sized pot. Heat the pot on a stove until the water is boiling. Turn the stove off and, wearing an oven glove, remove the pot from the heat source. When no longer boiling, pour the salt water into one toilet in your home and flush. Use this method if you are not satisfied with using undissolved rock salt; using the boiling method will allow the tree roots to more rapidly absorb chloride ions, resulting in a toxic build-up that is a more intense treatment of your tree root problems.

Repeat Step 1 or Step 2 once every two weeks if you are experiencing a severe tree root problem. If you sense there is a minor problem or are using rock salt for general maintenance, use the rock salt method once every one to two months to keep sewer lines clear of root problems. It is advisable to contact a plumbing service during and after use of rock salt to determine whether there was significant damage to pipes and to make repairs.


For root problems that do not occur within sewer lines, consult a professional. Rock salt will kill trees as well as nearby vegetation; pouring rock salt directly into soil may severely injure or kill your tree as well as other plant life. Additionally, if you do not notice a difference in your water flow after approximately three weeks, contact a plumbing service because the problem may require professional attention.

Things You'll Need

  • Rock salt
  • Medium pot
  • Measuring cup
  • Oven glove
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About the Author

Tarah Damask's writing career began in 2003 and includes experience as a fashion writer/editor for Neiman Marcus, short fiction publications in "North Texas Review," a self-published novel, band biographies, charter school curriculum and articles for various websites. Damask holds a Master of Arts in English and creative writing from the University of North Texas.