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How To Deal With Tree Roots In Your Septic System

Updated: Apr 14, 2023

Vector drawing of yellow house showing cutaway view of toilet, bathroom sink and kitchen sink drain lines running underground and tree roots in sewer line

Trees enhance curb appeal and work to shade your home in the summer, which helps with cooling costs. Tree roots, however, can spread into your sewer pipe or septic system and degrade their functionality. How do you know if tree roots are in your system, and what can you do to get rid of them without harming the environment? We’ve got your answers.

How Tree Roots Get into Your Septic System

Tree roots are always looking for moist nutrients, and your septic system is the perfect environment for them to seek out.

These are the entry points where tree roots most often enter your sewer line:

  • The lateral connection point where the city main connects to your home’s piping.

  • Cleanouts and T-fittings (a cleanout is a fitting typically installed at main elbows, the far end of the system, and where the system meets the municipality’s sewer system).

  • Between entry points covered by protective grease caps that are designed to protect these areas from tree roots but can fail over time.

  • Tiny cracks in the main line.

Tree roots that enter your sewer line or septic tank will spread in any direction and can grow up to 1 foot per day. Areas with high table levels near tree root bed areas are especially vulnerable because they force trees to look for sources of moisture that allow absorption of oxygen and water, which standing water won’t do.

Once in, tree roots cause significant damage by filling the space, causing clogs and slow drains that back up sewage into your home.

Signs You Have Tree Root Problems

The most common symptom of tree roots in your system is slow drains. Other signs include:

  • Sinkholes in the yard

  • Gurgling toilets

  • Fast tree growth – especially if one tree is growing faster than another

  • Spongy grass

  • Unpleasant smells in the yard

  • Foundation Issues

What You Can Do

In most cases, the best route is to call a professional plumber. While more expensive than trying to fix it yourself, they will have the right equipment to remove the roots and repair the sewer line so you don’t have more severe damage in the future.

If you have service line coverage with your homeowners insurance, it may cover the cost of repairing or replacing your sewer line. HO5 policyholders with Mutual Assurance have this coverage automatically.

If you want to try and remedy a tree root issue on your own, know that there are ecologically safe ways to do this, but it will need to be an ongoing effort as the spots where the tree roots are getting in will not be fixed.

DIY methods include:

  • DEP Root Kill - a bio-friendly powder you put in your toilet for several months, then twice yearly for maintenance.

  • Rock Salt – pulls moisture from the roots and eventually kills them. Two lbs slowly flushed down the toilet in ½ lb. increments. Allow the drain to sit for 12 hours without flushing. Good to apply before you go on vacation!

  • Potassium Chloride (K-Chlor) – is less expensive and works on maple, birch, pine, oak and elm trees. The trees will start showing brown tips after about two weeks of treatment.

  • Sodium Chloride – the most effective tree root killer, but very expensive.

How to Keep Septic Lines Clean Organically

One way to help prevent root issues or other drain issues is to use a monthly enzyme treatment that organically breaks down drain clogging build-up. Products like Zep Drain Defense or Septic Defense protect pipes and are simple, effective ways to protect your septic system.

To prevent root damage in the future, be mindful of where you plant trees in relation to your sewer line.



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May 03, 2023

The articles advice can cost you thousands of dollars and destroy your septic system. There is a difference between municipal sewer and a septic system. If you pour chemicals down your toilet and you have a septic system you will kill the anaerobic bacteria that make it work. Tongue in cheek, never put anything into your septic system that you haven't eaten first! If solids get into your drainfield you've destroyed it. Not fishing for business but between me and my coworkers we have over 250 years of experience dealing with septic issues.

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