Mix 1 cup of rock salt into 1 gallon of warm (not boiling) water. Pour slowly into the drain. The salt lowers the freezing point of water, helping to break down the ice plug. Do not use this on PVC or ABS pipes —the salt crystals can scratch the interior, creating future clog points. Step 4: Know When to Call a Professional If you cannot access the frozen section (it is behind drywall or 6 feet underground), or if you have tried gentle heat for two hours with no result, stop.
If you have self-regulating heating tape (the kind with a thermostat), wrap it around the frozen section. It will apply consistent, low-level heat over several hours. This is the safest unattended method. how to unclog frozen drain pipes
When a drain freezes, you are not dealing with a clog of grease or hair, but a solid plug of ice. The rules of engagement are different. Heat is your only tool, and patience is your only shield against costly pipe damage. Mix 1 cup of rock salt into 1