How to Kill Roots in a Sewer Line

A sewage drain pipe in a trench.
What You'll Need
Earth auger
1 1/2 PVC pipe
Female adapter
Copper sulfate
Protective eyewear
Hot water

Roots can show up in sewer lines even through very minuscule foundation cracks. Pouring salt into the sewer lines is a remedy that people often use, but that method can kill the tree along with the tree roots, leaving you with a potential hazard to your roof. Also, even if you hire a professional to come in and snake your sewer line, it will only provide a solution temporarily. However, getting rid of the roots permanently is easy enough to do yourself. You can clear the line and force the tree roots to grow in a different direction while avoiding killing the tree if you follow the simple steps below.


Step 1 - Locate Where the Sewer Line Is

You'll need to determine the exact location of the sewer line, and then assess how far into the ground it extends. If you have difficulty locating it, check with your city office and see if they can help you. You’ll also want to check with the local gas, cable, and electric companies to ensure that you won’t be interfering with any of their lines as well.

Step 2 - Mark the Pipe Location

Use two flags to mark where the sewer line comes from your house and where it connects to the city line. Then, draw a chalk line between the two points so you can keep track of the location of the pipe.

Step 3 - Drill Your Hole

Use an earth auger (you can rent one from a hardware chain store if you don't own one) to drill a hole into the ground that is about 2 1/2 inches in diameter. Stop when you get close to 30 inches right above the sewer line.

Step 4 - Insert Your Pipe

Take a 1 1/2 PVC pipe and cut it down to the length of the hole you drilled. Then, glue a female adapter on one end of the pipe, and insert the other end into the hole. The lip of the pipe should be flush to the ground, so if it’s not, take it out again and trim it down to size until it is the correct length.

Step 5 - Apply Copper Sulfate

Purchase a small or medium container of copper sulfate from your local home improvement, hardware, or gardening store. It can be located in the plumbing department or be found as an active degree in prepared root killers. Be sure to put on proper safety gear, such as gloves, a facemask, and protective eyewear, before handling this substance. Pour approximately four pounds down the pipe.

Step 6 - Use Hot Water

Next, get hot water and pour it down after the copper sulfate. You'll need to use about five gallons. Doing this will help the copper sulfate get absorbed more easily into the ground.

Step 7 - Repeat

Repeat this process every four months to keep the sewer lines clean. Be patient—it can take about a month or so before you completely get rid of the roots.


Step 1 - Fill Toilet with Copper Sulfate

Put on your safety gear, take out the same amount of copper sulfate as described above, pour it down the toilet, and flush.

Step 2 - Repeat

This time use only about 1/2 cup of the copper sulfate and pour it down the toilet. Keep repeating until you only have about 1/2 cup of the copper sulfate left from a two-pound box.

Step 3 - Leave the Solution Overnight

Take the last 1/2 cup of the solution, pour it into the toilet, and leave it in the bowl all night. Then, flush it down the drain in the morning. Make sure to do this about once ever six months.