Some tree roots are as small as a human hair. Because tree roots search for water, they will find tiny cracks in your pipes, especially at the joints, and enter the pipe, Once inside they grow quickly and can not only clog the drain but can also damage the pipe as they grown and push, causing the pipe to break. By using the simple root killer you can prevent root problems. You need to do this about twice each year. You pour it into the toilet that is closest to the main drain. Pour in a bottle and flush. After leaving you toilet alone for about 6 hours, it will be ready to uses again with no worry for another six months.