The answer to 'why is my sewer line frozen' is that sewer lines can freeze when the temperature drops below freezing for an extended period of time. This causes the water in the sewer line to freeze, which can block the flow of wastewater and cause backups in your home. Common causes include lack of insulation, poor drainage, and cold temperatures.
Symptoms of a frozen sewer line include slow draining sinks and toilets, gurgling sounds, and sewage backups. If you suspect your sewer line is frozen, it's important to act quickly to prevent further damage. You can try DIY solutions like pouring hot water down the drain or using a plumber's snake to break up the ice, but if the blockage is severe, you may need to call a professional plumber to thaw the line or replace the frozen section.