How to Stop Tree Roots in Sewer Lines
My guess is there are countless older homes within miles of where you live, many of them have ancient clay pipe sewer lines extending from the houses out to the city sewers. These clay pipes, with their mortar-filled joints, are notorious for allowing tree roots into the pipes. When that happens, the tree roots feast on the slurry of organic debris in the pipes, grow to freakish sizes, and eventually clog your sewer line.
What if I told you there’s an easy way to stop the tree roots from clogging your pipes? I’ll bet you’d jump for joy because roots in sewer lines always seems to create clogs on a Sunday night or when you have guests over to your home. I’ve used this method to prevent roots in pipes for years and it works like a dream.
You can watch a nice short video of me showing how to prevent tree roots from invading sewer lines by going here:
http://go.askthebuilder.com/treeroots
Degree of Difficulty: 
Step One: Make a trip to your local sewer department and ask to see the maps of your street. The public servants should be able to show you the location of the sewer tap in relation to the corners of your property adjacent to the street. Ask them how deep the sewer is in the street at your house. Locate the sewer clean-out fitting in your basement that almost always indicates where the building drain exits your home. Your outdoor sewer line runs between this point and the sewer tap at the sewer in the street.
Step Two: Purchase or rent a 2-inch earth auger. This is a hand-powered large drill that you twist into the ground to create a 2-inch diameter hole. Before using it, call 811 to have your underground utilities marked in your yard. You don’t want to drill through natural gas, electric, water lines, cable TV, telephone etc.
Step Three: Purchase 10-foot lengths of 1 1/2-inch PVC plumbing pipe, 1 1/2-inch female adapters and threaded plugs. Buy twenty-five pounds of copper sulfate crystals from a hardware store, feed store or an online merchant.
Step Four: Use a string between your house and the street to locate the above-ground location of your sewer line based on what you discovered in Step One. This string will ensure you drill holes in the soil above your sewer line.
Step Five: Sewer lines slope from your house to the sewer line in the street. You can determine the depth of the sewer line as it leaves your house based on how much lower your basement floor is than the ground outside your home. Add 16 inches as the sewer line must pass underneath the foundation footer of your home. Estimate the top of the sewer line as it passes underground using this information and what you gathered from the sewer department.
Step Six: Using the hand-powered auger, drill a series of holes spaced about 4 feet apart along the string line under any nearby trees that are close to the sewer line. Stop drilling when the bottom of the hole is about 2 feet above the top of the sewer line.
Step Seven: Insert a length of the PVC pipe into the hole, glue on the female adapter and make sure the top of the female adapter is flush with the top of the soil.
Step Eight: Pour into the pipe(s) one pound of the copper sulfate crystals. Add one or two gallons of hot tap water into the pipe to dissolve the crystals. Add more crystals and water each month for a period of three months. Always screw in the tiny plug into the female adapter to prevent the pipe(s) filling with debris.
Summary: Copper is a natural element that’s an effective biocide. The hot water dissolves the copper crystals and carries the copper into the soil that surrounds the sewer pipe in your yard. When tree roots attempt to grow into this soil, they’re repelled by the copper. The tree roots then just stay in the soil above the pipe instead of getting inside your sewer where they would otherwise cause havoc.
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