Before you begin, If only one fixture is backed up (e.g., the kitchen sink) but the bathroom works fine, it is likely a freeze. If no water works anywhere, you may have a frozen main water supply line.
A frozen drain pipe is more than an inconvenience—it can lead to burst pipes and water damage. Unlike supply lines, drain pipes (often PVC, cast iron, or ABS) hold waste water, so thawing requires care. Follow these steps to get water flowing again.
Thawing a frozen drain pipe requires a different approach than a pressurized water line, as you are often dealing with standing water and non-metallic materials like PVC. The safest methods involve applying gentle, consistent heat to the exterior or using safe mixtures to melt ice from the inside. Top Methods for Thawing Exposed Drain Pipes If you can reach the pipe in a crawl space, basement, or under a sink, use these external heat sources: Hair Dryer or Heat Gun
: If you see cracks, bulging, or icicles on the pipe, it has likely already burst. Shut off the main water valve immediately and call a plumber. Method 1: Applying External Heat (Best for Exposed Pipes)