Water expands as it turns to ice, and that pressure can split a pipe, but the split often leaks only when the ice melts. In Plymouth the damage tends to appear on the thaw. Shut off the main, start removal at once, and dry the structure; the EPA advises 24 to 48 hours.
Key takeaways
- Water expands when it freezes, which is why pipes split; the leak often begins only when the ice plug melts, so damage appears on the thaw and not during the cold.
- A regional news report said that after a February 2019 cold spell, calls came mostly on the thaw, which matches how a hidden split behaves.
- The first move is the main shutoff: know where it is before winter, because a split supply line can run for as long as nobody is home.
- Minnesota Department of Commerce tips, relayed through a legislator's newsletter, say frozen-pipe coverage is typical but a claim can be denied if a house was unoccupied without heat or if a slow leak ran for a long time.
- The EPA advises drying water-damaged materials within 24 to 48 hours, and walls and ceilings below a burst pipe need to be opened and measured, not judged by how dry the surface looks.
Why do frozen pipes leak when they thaw, not when they freeze?
Water expands as it freezes, and the ice plug can split the pipe or push a fitting apart. While the ice stays solid it also seals the break. When it melts, water flows through the split under full pressure, so the leak and the damage often begin during a warm-up, not the cold snap.
Water is unusual: it takes up more room as ice than as liquid, by roughly nine percent. In a pipe full of water that has frozen, that expansion has to go somewhere. The pipe wall can stretch, crack or split along a seam, and a threaded or soldered fitting can be forced apart.
The split is rarely where the ice is. A commonly described mechanism is that ice forms in one section and acts as a plug. Water between the plug and a closed faucet is trapped, and as more of it freezes, pressure builds in that trapped section until the weakest point gives. The crack may be inches or feet from the visible frost.
Because the ice plug blocks the opening, the pipe may seem to be fine through the freeze. A house can sit for days with a split pipe and no sign of trouble. Then the temperature rises, the plug softens, and water pours through the crack at normal supply pressure. If nobody is home, or the pipe is in a wall, the water can run for hours.
That is the pattern reporters describe. After a February 2019 cold spell, a regional news report said that calls arrived mostly on the thaw. It is also why advice on this page is about the warm-up as much as the cold.
Where do pipes freeze first in Plymouth houses?
Pipes freeze first where heat does not reach: exterior walls, attached garages, rim joist areas along the foundation, cabinets on outside walls, hose bibs and anything running through an unheated attic or crawl space. Plymouth's suburban stock has many attached garages and finished lower levels, so those spots are worth checking.
We have no sourced figure for the age of Plymouth's homes, but the city grew from farmland to suburb mostly from the 1970s onward, and houses from that era onward tend to have attached garages, finished basements and kitchens and baths on exterior walls. Each of those creates a cold spot. This is a general pattern, not a survey.
The kitchen sink on an exterior wall is the textbook case. The supply lines run into the cabinet, the back of the cabinet is the exterior wall, and a closed cabinet door holds back the warm room air. Lines that feed a bathroom over a garage are another, since the floor below is unheated space. Bonus rooms over garages are common in newer suburban plans and often have a long run of pipe inside a floor cavity that gets cold.
Utility rooms and finished lower levels matter too. A pipe near a rim joist, where the framing sits on the foundation, runs close to cold outside air through gaps around the framing. A water heater closet tucked against an outside wall can be cold at the back. Outdoor spigots that were left connected to a hose can freeze back into the wall.
A pipe does not have to be in a place nobody thought of. It just has to be somewhere that warm air does not circulate and that outside air reaches. Walk the house on a still, windy-cold day and feel along the floor and the base of exterior walls. A draft you can feel is a pipe in danger.
What can you do before a cold snap?
Keep the heat on and the doors of cabinets on exterior walls open, seal drafts around pipes and rim joists, disconnect hoses, and know where the main shutoff is. If you will be away, ask a trusted person to check the house, and keep the thermostat set high enough that pipes stay protected.
Prevention is dull and cheap by comparison. The steps below cover most Plymouth houses; none of them is a guarantee, and a very long cold spell can defeat any one of them.
| Where | What to do | Why it helps |
|---|---|---|
| Kitchen and bath cabinets on outside walls | Open the doors in the evening so room air reaches the pipes | Warm air is the heat source for those pipes |
| Attached garage | Keep the garage door closed, and insulate or move supply lines you can reach | Garages are rarely heated, and wind blows in through gaps |
| Rim joist and foundation edge | Seal gaps around pipes and wires with caulk or foam | Cuts the draft of cold air at the pipe |
| Outdoor spigots and sprinkler lines | Disconnect hoses in autumn and shut off and drain exterior lines | Water left in an exterior line freezes back into the wall |
| Unheated attic or crawl space | Ask a plumber whether any supply line runs there and can be moved | No heat source means the pipe depends on insulation |
| Main shutoff | Find it, label it and make sure it turns | A stuck valve is the worst surprise in a burst |
| Away from home | Keep the heat on, ask someone to check, or shut off and drain the system | An unoccupied house gives a leak all the time it needs |
What should you do if a pipe is frozen but has not burst?
Open the faucet the pipe feeds, then warm the pipe gently, starting nearest the faucet, with a hair dryer or warm towels. Never use an open flame. If you cannot find the frozen section, or you see a split, shut off the main and call a plumber.
A faucet that gives only a trickle or nothing at all in freezing weather is the usual sign. Opening it matters because it gives melting water an outlet and relieves pressure. Heat should be gentle and should move toward the blockage, so melted water can drain out through the open tap.
Do not use a torch, a propane heater pointed at the wall or anything with a flame. Flame can ignite framing and insulation, and an overheated pipe can fail. If the frozen section is inside a wall and you cannot reach it, raising the room temperature and opening cabinet doors may be all you can do. Call a plumber.
Keep watching after the water returns. Walk the area, look at the ceiling beneath, and check the water meter if you have one. A meter that moves with every tap closed is telling you something. Plumbing repairs must be done by licensed tradespeople in Minnesota, so call a plumber for the fix and a restoration company for the drying.
What should you do when a pipe has burst?
Shut off the main water valve first, then turn off power to wet areas if you can do so safely. Photograph the damage, remove standing water and open cabinet doors to get air moving, and call a restoration company at once. The EPA advises drying water-damaged materials within 24 to 48 hours.
The order matters. The water supply comes first, because every minute of flow adds to the loss. If the main is in a wet lower level and the floor is flooded, do not wade in until power to that area is off. If you cannot do that safely, leave the house and call for help.
Next, protect what you can. Lift contents off wet floors, move rugs and furniture, pull up wet carpet in corners if you can do so safely and put foil or plastic under furniture legs. These are stop-gaps; the structure is the real work. Water in a wall cavity travels along framing and spreads under flooring, so a small wet patch on the surface can hide a much larger area behind it.
Call (833) 490-5225 to be connected with an independent local licensed company; crews are dispatched around the clock as fast as one is available. We cannot promise a time, so keep doing the steps above while you wait. Our pages on burst pipe water damage and frozen pipe water damage describe what the crew does when it arrives: extraction, moisture mapping, drying equipment and checks until readings are dry.
Does home insurance cover frozen pipes, and what is the heat condition?
Per Minnesota Department of Commerce tips as relayed in a legislator's newsletter, frozen-pipe coverage is typical, but a claim can be denied if the house was unoccupied without heat, or if a slow leak ran for a long period. Your own policy wording decides, so ask your insurer what it requires.
We have not read the Commerce page directly; what we have is the guidance as relayed in a 2019 legislator newsletter and in news coverage, so treat the points below as questions to put to your insurer, not as a statement of what your policy covers.
The heat condition is the one that surprises people. Insurer guides often mention a minimum thermostat setting for a vacant or seasonal house, and the figure commonly quoted is 55 degrees Fahrenheit. Treat that as a hedged example from insurer guides; your policy may say something different, or may require that the water be shut off and drained instead. Ask what applies to you.
Two other points come up in the guidance. Report the loss promptly and get a claim number. And be careful with the word flood: a pipe that splits is not a flood in the insurance sense, and describing it that way may send the conversation in the wrong direction. Say what happened in plain terms.
Slow leaks are a separate issue. A pipe that drips for weeks behind a wall, a fitting that weeps or a supply line that was never right is not the same as a sudden split. Look for stains, a musty smell or a rising water bill. Neither this site nor Plymouth Water Damage Restoration can say what an insurer will decide.
- Does my policy require a minimum temperature or occupancy for coverage to apply?
- What do I need to do if I will be away for a week or longer?
- How does the policy treat water that leaked slowly over a long period?
- Will you approve the drying scope before it starts, and who is paid directly?
- What do you want to see: photographs, a plumber's invoice, moisture readings?
What happens after the water is stopped?
A crew extracts standing water, then maps moisture in floors, walls and ceilings with meters and places air movers and dehumidifiers. Walls and ceilings below a burst pipe often need opening so cavities can dry. Drying continues until readings reach dry levels, which commonly takes several days.
The visible water is the smaller problem. Drywall, insulation, subfloor and framing absorb water and hold it, and a house that is closed up against the cold dries slowly. Dehumidifiers do most of the work in winter, because opening windows brings in air that is cold but not necessarily dry.
Ceilings are a frequent victim of a split above. A brown stain or sag means water is trapped on the drywall; leaving it is how ceilings fall and mold starts. A crew may cut small openings to release water and let air in, which is easier to patch than a collapsed ceiling. Our ceiling water damage page covers that case.
Mold is the long-term risk if drying is incomplete or late. We cover how to judge it, and what to ask a company, in the guide on mold after water damage in Minnesota. Rebuild work such as drywall, flooring and trim can fall under Minnesota Department of Labor and Industry residential contractor licensing, so ask who does it and check the licence on the department's lookup.
Frequently asked questions
Why did my pipe burst when it was thawing?
The pipe likely split during the freeze, but ice sealed the break. When the ice melted, water flowed through the crack at supply pressure, so the leak started on the warm-up. This is why damage often appears after the coldest days have passed.
How long does it take to dry a house after a burst pipe?
It depends on how much water, how many materials were wet and how cold the house is. The EPA advises drying water-damaged materials within 24 to 48 hours, and crews keep equipment running and measure until readings are dry, which often takes several days.
Will my insurance cover a burst pipe?
Per Minnesota Commerce tips as relayed, frozen-pipe coverage is typical, but a claim can be denied if the house was unoccupied without heat or a slow leak went on a long time. Your policy decides, so ask your insurer. We cannot predict an outcome.
What temperature should I leave the heat at when I am away?
Insurer guides often quote about 55 degrees Fahrenheit, but your own policy may say something different or require the water to be shut off and drained. Ask your insurer which applies, and ask someone to check the house.
Should I use a torch or open flame to thaw a pipe?
No. Open flame can ignite framing and an overheated pipe can fail. Use a hair dryer or warm towels, working from the faucet back toward the frozen section, and keep the faucet open. If you cannot reach the freeze, call a plumber.
Do I need a licensed plumber to fix a split pipe?
Yes, plumbing work in Minnesota is done by licensed trades according to the summaries we saw. A restoration company dries the structure; a plumber repairs the pipe. Ask both for a written price before work begins.
Sources
This guide is general information for Hennepin County homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.