Frozen pipes in Michigan: thaw one safely, stop the next one

What the state tells Michigan homeowners about frozen pipes

The most useful short document is the State of Michigan’s own page on preventing frozen pipes, part of its MiReady winter preparation material. It makes a point that is easy to miss: the pipes most likely to freeze are the ones in crawl spaces and attics, not the ones you picture buried in a cold yard. If your house has a run of pipe passing through an unheated corner, that run is your risk.

The same page gives the scale of the problem. It attributes to the Michigan Committee for Severe Weather Awareness an estimate that a quarter-million homes are damaged each winter by frozen pipes, and says an eighth-inch crack can leak up to 250 gallons a day. The page is undated and the figures are the committee’s, so treat them as a state estimate and not as this year’s count. The eighth-inch crack is the more useful number, since a small crack can lose a lot of water before anyone notices it.

Frost depth is a footing rule, not a pipe rule

You will see “42 inches” quoted as Michigan’s frost line. The number is real. It comes from Michigan Administrative Code R 408.30522, which amends the residential code to read that all exterior footings and foundation systems shall extend 42 inches below actual grade. The building official may change that depth when there is evidence about freezing degree days, soil type, ground water, snow depth, exposure or other site conditions.

That rule keeps a foundation from heaving, and it says nothing about how deep a water service line must be buried. Read 42 inches as no promise that your water line is safe. If your service line runs under a walkway or through a garage, a plumber who has seen it can tell you more than a number on a map.

Before a cold snap

The state’s advice is mostly cheap.

• Insulate pipes in crawl spaces and attics.
• Seal air leaks near pipes.
• Disconnect garden hoses, and drain outdoor faucet lines.
• If you use heat tape, use only tape tested by an independent laboratory such as UL.
• If you are leaving town, keep the thermostat no lower than 55 degrees.

One more step is ours rather than the state’s: find your main shut-off valve while the weather is mild and and turn it once, so you know it moves. The know your shutoff tool shows what to look for.

When a pipe freezes

The first sign is usually a tap that gives nothing, or a trickle where there was a stream. Check whether one fixture or the whole house is affected: a single dry tap on an outside wall suggests a local freeze, while a dry house suggests the line coming in.

The state’s instructions for a frozen pipe are short, so we repeat them as written:

1. Shut off the water at the main valve.
2. Warm the pipe with a hair dryer, starting near the faucet and working back toward the frozen part.
3. Never use a torch or open flame.
4. If nothing comes out of the tap, call a plumber.

We leave out the other thawing tricks you will find online, because the state does not endorse them. If you cannot reach the frozen section, because it is inside a wall or under a slab, stop there. Opening a wall is a plumber’s decision, and emergency plumber explains how to ask for one.

If the pipe has already burst

Water comes first, so close the main valve, then move belongings out of the way and start making calls. A burst pipe means leak repair on the plumbing side and your insurer on the money side.

Michigan’s insurance regulator, DIFS, advises telling your insurer that you have water damage rather than simply calling it a flood. Causes such as sewer back-up or a failing sump pump may be covered under the policy even when flood damage is not, and the wording of your own policy decides, so read it or ask your agent. Photograph the damage before anything is moved; that is common sense and not a rule.

Hiring a plumber in the middle of the night

A call at 2 a.m. is when people skip checks, and two habits protect you. The first is the license. Michigan requires a license for plumbing work, and LARA’s public lookup lists plumbers under Skilled Trades. The steps are in how to find a licensed plumber in Michigan. It takes a few minutes on a phone, and it is best done before the truck is in your driveway.

The second is money: before work starts, ask about the call-out fee, what it includes, and the hourly rate if the job runs long. Our estimate for emergency plumbing labor is $105 to $535 per hour of labor, before any call-out fee, a model and not a quote. The wage figure from the Bureau of Labor Statistics, a $37.14 mean hourly wage for Michigan plumbers in May 2025, measures what plumbers are paid, which is a different thing from what you will be charged. How much a plumber charges per hour in Michigan goes through the difference.

After the thaw

A pipe that froze once has shown you a weak spot. Start with the state’s prevention list of more insulation, sealed gaps and care with heat tape, and watch the area for damp patches over the following weeks. If a plumber finds the cause, ask what they would change to stop it happening again.

Sewer and drain trouble after a thaw is a different problem, and it has its own guide: sewer backup after heavy rain in Michigan.

Where this guide’s evidence stops

Everything here about thawing and prevention comes from the State’s own winter preparedness page, with no frozen-pipe guidance from MSU Extension to set beside it, and we located no Michigan rule on burial depth for a water line. If you are planning new outdoor plumbing, ask the plumber and your building department what depth they require where you live.