I Ignored a Dripping Garden Tap All Winter — Then Found the Pipe Split in Spring

What Freezing Water Does

You probably know water expands when it freezes. That’s eighth-grade science, and it’s absolutely true — roughly 9% more volume as ice.

What I didn’t appreciate is that a pipe full of ice doesn’t necessarily split right where the ice forms.

When water freezes inside a pipe, it creates a solid plug. That plug traps water between itself and the closed valve downstream. As more water freezes and expands, it pressurizes the liquid water still trapped in that section.

Think of it like squeezing a toothpaste tube with both ends capped. Something has to give.

The copper doesn’t fail where it’s coldest or where the ice actually sits. It fails at the weakest point along the pressurized section — often a joint, a bend, or a thin spot in the wall.

In my case, that was right behind the brick, where the pipe made a 90-degree turn into the house. The cold Minnesota air hit that elbow hard, but the real killer was hydraulic pressure from ice forming closer to the valve.

So why did the drip make it so much worse?