The answer to 'my water line smells bad' is that a foul odor in your home's water supply is usually caused by bacterial growth, mineral buildup, or a problem with the water heater. Common symptoms include a rotten egg or sewage-like smell, discolored water, and strange tastes.
Some potential causes and solutions include: 1) Bacteria in the water line - This can be treated by shocking the system with chlorine or replacing the water filter. 2) Mineral buildup - The pipes may need to be flushed or replaced. 3) Issues with the water heater - The anode rod may need replacement or the tank may need to be drained and cleaned.