Best for: Metal or PVC pipes (Safe and gentle).

Best for: Targeted thawing.

If you have tried these methods for over an hour with no result, or if the pipes are located inside a wall or underground where you cannot apply heat, it is time to call a plumber. They have professional steamers that can clear blockages deep within the system without damaging your home.

: In unheated basements or crawlspaces, you may see physical frost on the outside of the P-trap. How to Thaw a Frozen Drain Trap Safely 1. The Salt and Hot Water Method (Internal)

If you know a deep freeze is coming overnight, let a very thin stream of cold water run from the faucet. Moving water takes much longer to freeze than standing water in the trap.

| Problem | Solution | |---------|----------| | Pipe runs through an exterior wall | Open cabinet doors during extreme cold to let warm air in. | | Drafts from outside | Insulate the pipe with foam pipe insulation (available at hardware stores). | | Unheated garage or basement sink | Wrap the trap with heat tape (electric heating tape designed for pipes). | | Cabinets against cold exterior wall | Place a small, low-wattage bulb inside the cabinet (LED won’t work—use incandescent or a “pipe warming” bulb). |