I removed a few soup cans full of small roots from my main drain with a power auger (snake). I have no way of knowing how far in the line these were growing but I suspect it was the toward the end. The unfortunate thing is, the auger was 100' long but the line is probably 125'; there may be more beyond but the water is flowing well now.
I was introduced to copper sulfate as a possible remedy. I'm skeptical. The container claims it kills roots and is to be used while there is still flow but I wonder just how effectively it does kill roots. Instructions call for anywhere from 2 to 5 pounds to be flushed down a commode twice a year.
Will someone with some understanding of how copper sulfate really reacts with small roots in a drain please comment.