[upd] - Shower P Trap Frozen

Bottom line: Be patient, use gentle heat, and never rush to pour chemicals into ice.

Here’s what you need to know to fix it safely.

The P-trap is that curved pipe under your shower. Its job is to hold a small amount of water to block sewer gases. Because that water sits stagnant, it’s vulnerable to freezing when frigid air leaks through uninsulated walls or a poorly sealed foundation.

Discovering that your shower won’t drain—and that the water is backing up into the pan—is frustrating. If it’s the middle of winter and your bathroom is on an exterior wall, the likely culprit is a frozen P-trap.

If the blockage is ice, chemical drain cleaner will simply pool on top of it. When it eventually thaws, you’ll have a highly corrosive liquid surging through your pipes—dangerous for you and potentially damaging to old metal plumbing.