Here is a SMART TIP from The Ultimate Guide to Plumbing by Merle Henkenius
Clearing the underground sewer line between your house and the street is NOT for most homeowners as it can be very tricky.
You want to be careful not to break the cable from the auger off into the sewer service. You can do this by listening very carefully to the motor, feeling and listening to the resistance of the cable so that you can sense the difference between tree roots, a broken pipe, piping offsets and the juncture of private sewer service and public sewer main.
Actually, you are probably best to call a professional. We just happen to be professionals. Call City Wide Plumbing and Service Company at 480-966-8795 today!