If hot water alone isn't cutting it, you can lower the freezing point of the ice using salt.
When extreme freeze warnings occur, open your faucets to a slow, steady drip. Moving water resists freezing much better than standing water. Maintain Consistent Home Heat
Wrap a damp rag around the hose nozzle to create an airtight seal.
Wrap all vulnerable drain lines in foam pipe insulation sleeves. Pay special attention to unheated zones like crawlspaces, attics, and external walls. Let Faucets Drip