replace the line. once roots invade, there is no other "permanent" fix.

Is there any alternative to digging up the line and replacing it ? The line goes through a protected wooded area or at least the tress are historic or something so cant be cut down.
thanks
ani

If you are on a shared sewer line and you are the lowest house, it would seem that the blockage is downstream of your house and not in your house. When all the homes above you run water it backs up into the lowest point..your house.
Since this is a shared line it would seem that the group of houses (if this is a private line) should be responsible for the repair/replacement. If it's a municipal system, then the city would be responsible.

You could abandon the existing line and install a new one. instead of removing the existing line. Either way, a new line is most likely necessary.

One possibility would be to try the video camera approach, and find the exact location and nature of the problem(s). That way you might be able to just replace a small piece of the line, depending on the problem. This would disturb the trees a lot less.

This inspection will cost a lot less than blindly launching into a major project.

-Roger

My sister went through this, eventually, had the tree cut down, trunk ground up, five yrs later, neighbors tree found her pipe, plumber said she could try root drain killer but he didn't have faith in it, other option is to have line cleaned every two yrs he said,line cleaned but roots still right there at the pipe wall. You being on a shared line, seems only fair the bill gets shared.

is the "shared" portion of the line owned by the homeonwers or by the municipality? in my area it is illegal to share the line, each home must have it's own line to the muni sewer. if the muni own the portioin of the line that is blocked, then THEY have to fix it at no charge.

your best bet is to get the plumber to run a camera as suggested earlier. they can then tell if the problem is yours or someone elses.

BTW, if we shared a line and your tree was causing backups into your house, i would tell you YOU need to have the problem resolved unless there was a binding contract requiring all repairs to be split evenly.

After 10 years of cleaning roots every six months, we abandoned part of the original line, ran a new line to connect to the old one, and replaced the old one all the way to the street with PVC. Trees were the problem preventing running along the original path. Before doing any of that we ran the camera.