I second the recommendation of O’Neill Plumbing. They have done both water main and sewer replacement for us, and I could not recommend more highly. They had great communication, and did not immediately jump to the most costly option – rather, they estimated a phased approach and only charged more depending on what they found.
I would recommend having a qualified plumber look at this versus going the Home Depot route. Your situation sounds a lot like mine (and others I know) who have had an old pipe partially collapse. I certainly hope it’s a clog, but if it’s to the point where it’s backing up to a point of origin, just be prepared for something more major. They may recommend a camera inspection, which will tell you what’s really going on. More $$, but the peace of mind is worth it. Good luck!
