The answer to 'how to unclog sewer repair' is to first try using a plunger or a drain snake to clear the clog. If that doesn't work, you may need to use a sewer auger or call a professional plumber. Sewer clogs can be caused by a variety of issues, such as tree roots, debris, or a collapsed pipe, and require the right tools and expertise to properly diagnose and fix.
It's important to take safety precautions when working on a sewer line, such as wearing gloves and eye protection, and ensuring proper ventilation. If the clog is severe or you're unsure of the cause, it's best to call a professional plumber to avoid further damage or health hazards.