willows are SERIOUS sewer finders, truthfully, i would kill and remove the tree first. but they’re pretty trees and you’d pry like to save it. do remember that your sewer line is already broken. that is how the roots are able to slow your drain,it may not cause severe problems for years and i wouldn’t dig it up until it does, but rodding it often will possibly make the problem worse because the sewer machine may break the pipe further. get it rodded now, but immediately start using root killer down your drain and continue to use it every 4 months or so. root killer is simply copper sulfate in granuals about the size of your fingernail. you can buy root killer at your hardware store or if your lucky you may have a chemical supply place you can access. like i said, about a pound of copper sulfate, every 4 months right down your toilet(you may have to push it over the trap with your hand, yuk!) should keep that willow at bay. it doesnt kill the tree, just the roots in your sewer. good luck jill! jack