Michigan Frozen Pipe Prevention Guide: A Winter Playbook for Homeowners

Michigan winters do a specific kind of damage to plumbing that milder climates do not. The reason is not just that it gets cold — it is that it gets cold, then warm, then cold again, repeatedly, for months on end. That freeze-thaw cycle is the worst possible condition for any building material that holds water, because each cycle works ice deeper into small gaps, expands hairline cracks in slabs and foundations, and repeatedly loads and unloads pipes with the pressure of nearly-forming ice. A pipe that survived last winter is not necessarily going to survive this one, because the failure points are cumulative.

Add in the polar vortex events that have become a regular feature of Great Lakes winters — multi-day stretches in the single digits or below zero with serious wind — and you get conditions where even well-built homes can lose pipes in places their owners never thought to worry about. The wind is the under-discussed variable here. An exposed pipe behind an exterior wall that would be fine at 15°F with still air can freeze in a couple of hours at 15°F with a 25 mph wind driving cold through every unsealed gap in the siding.

The other Michigan-specific factor is housing age. A large share of homes in Bloomfield Township, Birmingham, Royal Oak, and Ferndale were built between the 1920s and the 1960s, and those homes were built with assumptions about insulation and pipe routing that look questionable today. Copper supply lines running through uninsulated exterior walls, hot-and-cold pairs feeding a second-floor bathroom through an attic soffit, laundry hookups on a garage wall — these are normal in older Oakland County housing stock, and every one of them is a freeze risk a newer build would not have. See our main water damage restoration page for what happens on the cleanup side when one of those runs lets go.

One of the most widely repeated ideas about frozen pipes is also slightly wrong, and understanding why matters for prevention. The common version is that ice expands inside the pipe and cracks it open from the inside out. That is close, but it is not quite what happens.

What actually happens is this. As water in a section of pipe freezes, an ice plug forms and begins to grow. The plug blocks flow. Upstream of the plug — between the ice and the closed faucet or valve at the other end of the run — there is still liquid water, and that liquid water is getting squeezed by the expanding ice. Pressure in the trapped column rises rapidly, and because water is effectively incompressible, all of that pressure has to go somewhere. It goes into the weakest point in the pipe wall, the weakest fitting, or the weakest valve. That is where the split or the blown connection happens, and it is often several feet away from the ice plug itself.

This is also why dripping a faucet works. A faucet that is cracked open gives the trapped water a place to go. The pressure never has a chance to build, because the column is not actually sealed. The ice plug can still form, but a frozen pipe without a pressure rupture is a manageable problem. A frozen pipe that has split open while you were sleeping is a flooded first floor.

Open the cabinet doors. Under-sink cabinets on exterior walls — kitchen sinks and bathroom vanities especially — trap cold air against the pipes inside. Leaving the doors open lets warm room air circulate through the cabinet and keeps the supply lines several critical degrees warmer.

Drip the faucets farthest from the main. A pencil-thin stream of cold water from the fixture at the end of the longest run, overnight, on the worst nights. If you have a known-vulnerable bathroom — second floor, exterior wall, has frozen before — drip that one instead or in addition.

Do not let the thermostat drop overnight. Programmable setbacks that save money in normal weather are not your friend during a polar vortex. Hold the daytime setting through the night.

Check the garage door. Close it, keep it closed, and check for obvious drafts at the weatherstripping.

Have the main shutoff ready. If the house has adults who are not confident about finding and operating it, take thirty seconds at the start of the cold snap to show everyone where it is.

The first move is to open the faucet served by the frozen section, both hot and cold, so that when the ice plug starts to melt the water has somewhere to go. This is the single most important thing you can do in the first minute, because it converts a pressure bomb into a slow drip.

The second move is to apply gentle, indirect heat to the exposed section of pipe, working from the faucet end back toward the frozen section rather than the other way around. A hair dryer moved slowly along the pipe, a small space heater positioned a safe distance away, or warm damp towels wrapped around the pipe are all reasonable methods. Never use an open flame — a propane torch pointed at a wall is how house fires start.

If the frozen section is inside a wall, behind finished drywall, or otherwise not visible, do not start cutting. Shut off the main, turn the heat in the affected room up as high as the thermostat allows, and call a licensed plumber. A plumber with a thermal camera can locate the frozen section without guessing, and that is cheaper than the drywall and flooring repairs that follow an exploratory hole in the wrong place.