Tree roots in your septic system lateral lines prevent effluent water from flowing from the tank. Blue copper sulfate crystals kill the roots that cause the problem without harming the tree. The dead roots deteriorate, clearing the line.
Locate the septic system distribution box
This box connects the septic tank to the lateral lines, allowing water to flow evenly through the lines evenly. Your local building department often has an as-built drawing, which is a map showing the components of the septic system. It shows the location of the distribution box if the system uses one.
Add copper sulfate to the distribution
Once you locate the distribution box, remove the soil from the top, and lift the lid. Add 2 pounds of copper sulfate to the box. Use water from a hose to wash the crystals through the lines.
Flush through the toilet
Some systems don't have a distribution box. In this case, flush the copper sulfate down the toilet. Add 1/2 cup of crystals, and flush the toilet to move them through the system. Repeat until you have flushed 2 pounds of the root killer down the toilet. This method takes longer to kill the offending roots, as the chemical must work its way through the septic tank.