Hello Highland Park neighbors, Based on recommendations from you for reliable plumbers, I used two plumbers from the list to locate and fix a serious clog in the main sewer line at my home: . A1 Sewer Cleaning Specialists 412-664-4212: They do only main line sewer cleaning. A1 technicians checked the line from the house to the street connection, and found no clog. Since A1 Sewer does not do plumbing repairs, they recommended I engage a full service plumber to diagnose the problem in the house plumbing. There was NO CHARGE for their service since the could not clear the clog. . Stahl Plumbing: 412-273-1000: Opened the main sewer line inside the house, located the clog (roots in the line), and cleared the problem. Stahl technicians also diagnosed or fixed several other nagging plumbing problems while there. It took them about two hours from start to finish, including the time it took to auger a large root growth from the main sewer line. The charge was about half what I expected it to be, so I was very pleased with that! Both companies showed up when promised, did the job I requested in a quick, clean, and professional manner. I highly recommend them both, and plan to call them again when I need plumbing services. Best regards, --Joel