1. First, Confirm It’s Really Frozen Before assuming ice, rule out a standard clog.
| Location | Typical situation | |----------|------------------| | (just below the drain strainer) | Shallow trap in unheated crawlspace or garage below. | | Horizontal run (from trap to main stack) | Pipe passes through an uninsulated exterior wall or unheated space. | | Main stack / soil pipe (rare) | Entire house drain is frozen – usually affects toilets first. | shower drain is frozen