Because you are responsible for repairing and replacing your home's sewer line, it is important to do all you can to prevent any damaging effects on the line. When you have trees growing in your front yard, you may not want to remove them, as they provide shade to your home and help cool your home during the summer. But, replacing an average-size main sewer line in your front yard can cost from $3,000 to $6,000, with extra costs for repairing and replacing your yard's landscaping and any pavement damage that occurred during the excavation and repairs. Here is some information to help you prevent tree root growth around and into your sewer line, to help prevent sewer line damage.
Use Copper Sulfate
The first step to protecting your home's sewer line from invasive tree roots is to treat the soil around your home's buried sewer main with copper sulfate, which you can find at most home improvement stores. Tree roots will avoid the copper sulfate in your soil and stay away from your sewer line. Copper sulfate only affects the tree roots that come into contact with the chemical, instead of killing the entire tree and its roots system, such as when you use salt as a root treatment in your sewer line.
Find Your Sewer Line
Determine the location and depth of your sewer line in your home's yard and where it extends out to the city's sewer main. You can do this by checking with your local zoning office to look at a map of your property that includes sewer line locations in your yard. You can also inspect your home's basement or crawlspace for visible sewer pipes, following your home's sewer line to where it exits from your home. Then, you can follow that line's location outside your home to the city's sewer main. For example, begin your search with a toilet plumbing line and follow that visible basement or crawlspace line until it connects to a larger pipe, continuing until you get to the home's main line that exits your home's basement or crawl space.
If your home does not have accessible sewer lines in your basement or crawlspace and you don't want to look for sewer lines in floors or behind walls, you can hire a plumbing services professional to locate the line in your front yard using GPS, then mark the line's location in your yard with chalk or contractor's spray paint.
Treat Your Soil
Any sewer line that runs through soil that is nearby or below tree growth should be treated with copper sulfate to prevent root damage. First, use a soil auger to dig a hole down to the soil above your sewer main's location. The hole only needs to be two to three inches wide for you to insert a length of PVC pipe 1 1/2 to 2 inches in width for the treatment. Make sure the PVC pipe extends up from the ground so you can keep it clear of soil as you treat the soil with copper sulfate. Cap off the pipe with a PVC end cap, so you can repeat the soil treatment process periodically, as needed.
To complete the treatment, fill the pipe with copper sulfate, then pour down several gallons of hot water, which will dissolve the copper sulfate and allow it to saturate the soil around the sewer line. If there are still copper sulfate crystals remaining in the pipe, repeat the flushing process with boiling water.
Treat Your Sewer Line
It is important to follow up this soil treatment by treating your sewer line internally. To do this, regularly pour 1/2 cup of copper sulfate into your toilet and allow it to sit overnight. In the morning, flush this down the pipes and it will enter your sewer main and kill any tree roots than may be trying to grow into your sewer line.