How do I unclog the main sewer line myself?

First you’ll need to locate the sewer clean out, open it carefully, and stand back in case wastewater is under pressure. Use a heavy-duty drain snake to reach the clog, twisting as you push to break it up, then pull it back and flush the line with lots of water. If that doesn’t work, try a plunger on the nearest drain, or a hot-water flush for minor buildup. Avoid chemical drain cleaners, since they can damage pipes and won’t usually clear a main-line blockage. Stop and call a plumber if sewage backs up, the snake won’t advance, or you suspect a collapsed or root-blocked pipe.