Frozen Pipes: How to Get Through a Hard Freeze Without a Burst

Most burst pipes do not start with a dramatic crack in the middle of the night. They start quietly, on the coldest night of the year, in a pipe you never think about: the one running through an outside wall, across an unheated garage, or under a kitchen sink on the north side of the house. Water inside it turns to ice, the ice expands, and pressure builds in the section of pipe trapped between the ice and a closed faucet. Something has to give, and it is usually a joint, a fitting, or a weak stretch of pipe. The flood you find in the morning is the end of that story, not the beginning.

The good news is that a hard freeze is not a lottery. Pipes freeze in predictable places, for predictable reasons, and most of the steps that prevent it cost nothing or close to it. This guide walks through the whole sequence: what to do before the cold arrives, what to do while it is here, how to handle a pipe that has already frozen, and what to do if one has already split. The goal is simple. Get through the freeze with your plumbing intact and your floors dry.

People picture ice splitting a pipe right where the ice formed, like a sausage splitting in a pan. That happens sometimes, but the more common failure is different and worth understanding, because it changes where you look for trouble. When water freezes inside a pipe, it forms a plug. Water trapped between that plug and a closed tap has nowhere to go, so pressure climbs along that whole trapped section. The pipe tends to fail at its weakest point, which might be several feet away from the ice itself, often at an elbow, a soldered joint, or a spot that was already stressed.

That is why a plumber will sometimes find the split in a warm-looking stretch of basement pipe while the actual freeze happened in a cold wall cavity. It also explains why opening a faucet matters so much during a freeze. A faucet left dripping gives trapped water somewhere to go, which relieves the pressure that actually does the damage. The drip is not about keeping water moving for its own sake. It is a pressure release valve you already own.

Not every pipe is equally at risk. The usual suspects are pipes in outside walls, pipes in attics, crawl spaces, and garages, pipes near foundation vents, and the supply lines to hose bibs on the outside of the house. If you have ever had a bathroom that runs cold in winter or a kitchen sink that loses pressure on frigid mornings, you probably already know which runs in your house are marginal. Those are the ones to protect first.

The best time to prepare for a freeze is a calm afternoon before the forecast turns ugly, not at midnight when the temperature is already dropping. Walk your house with fresh eyes and look for the places cold air gets in. Foundation vents near pipes, gaps where a pipe passes through a wall, a garage door that does not seal, a crawl space hatch that never quite closes. Cold air does not need a big opening. A steady draft across a pipe on a windy night will do the job that a cold room alone might not.

Start outside. Disconnect garden hoses from outdoor faucets and drain them, because a hose left connected traps water in the faucet and the short pipe behind it, which is exactly the section that freezes first. If your outdoor faucets have frost-free sillcocks, they still need the hose off to drain properly. If they have interior shutoff valves, close those valves and open the outdoor faucet to let the short run drain. Put the hose away coiled, not draped over the faucet where it will freeze solid and be useless in spring.

Inside, find your main water shutoff valve before you need it in a panic. It might be near the water meter, where the main line enters the house, in a utility room, or in a basement on the street-facing wall. Turn it once, gently, to make sure it actually moves. A shutoff valve that has not been touched in ten years can seize, and discovering that while water is pouring through a ceiling is a bad moment. Show everyone in the household where it is. This one habit is worth more than any gadget, because a burst pipe that runs for five minutes is a mop-up, and one that runs for five hours is a renovation.

Insulate the pipes you can reach. Foam pipe sleeves slide over exposed runs in basements, crawl spaces, and garages, and they are cheap, quick, and genuinely effective on the runs they cover. Pay attention to elbows and fittings, which are the spots people skip and the spots that fail. For pipes inside outside walls, you cannot easily insulate the pipe itself, but you can reduce the cold reaching it by sealing air leaks in that wall cavity from the inside and outside, around outlets, vents, and where the siding meets the foundation.

Finally, think about the rooms that get cold because nobody uses them. A spare bedroom with the door shut and the vent closed can drop well below the rest of the house on a hard night, and the bathroom pipes in its outside wall are sitting in that cold. During a freeze, keep interior doors open so warm air circulates, and do not close vents in unused rooms all the way. Heating a room you are not sleeping in feels wasteful. Replacing its plumbing feels worse.

When the hard freeze arrives, the playbook is short and it works. First, let faucets on outside walls drip. You do not need a stream, a steady drip from both the hot and cold taps is enough, and the faucets to prioritize are the ones fed by pipes in outside walls. If you have to choose because of a septic system or a well pump you are worried about, choose the fixtures on outside walls and the ones farthest from where water enters the house. Those are the runs most likely to freeze, and the drip protects them by relieving pressure.

Second, open the cabinet doors under kitchen and bathroom sinks on outside walls. The warm air in the room needs to reach the pipes, and a closed cabinet door is a surprisingly effective insulator working against you. If you have small children or pets, move cleaning products out of those cabinets first, then leave the doors open overnight. It looks untidy. It works.

Third, keep the thermostat steady. The night of a hard freeze is not the night to set the temperature back aggressively or to let the house cool while you are away. A consistent temperature through the night keeps wall cavities above freezing, and the heating cost of one cold night is small next to a plumbing repair. If you will be away during a freeze, do not turn the heat off. Set it to hold a normal lived-in temperature and have someone check the house if the cold spell lasts more than a day or two.

Fourth, keep the garage door closed. A garage is often the coldest attached space in the house, and water lines to a laundry room, a bathroom, or an outdoor faucet often pass through it or through the wall it shares with the house. An open garage door on a windy freezing night can drop the temperature around those pipes fast. If your garage has its own water supply or a utility sink, that room deserves the same attention as any other.

Watch for the early warnings. A faucet that slows to a trickle on a cold morning, a toilet that refills oddly slowly, a shower that loses pressure while the rest of the house is fine: these can all mean ice is forming in one run. Do not wait to see if it clears up on its own. Open the affected faucet, open nearby cabinets, get warm air to the area, and start looking for the cold spot in the run, which is often near an outside wall, a vent, or a drafty corner.

If a faucet gives you nothing on a freezing morning, assume a pipe has frozen and act on that assumption. First, open the faucet that the frozen pipe feeds, and leave it open. If the pipe thaws, water needs somewhere to go, and an open faucet also relieves pressure while you work. Then open nearby faucets too, so you can tell when flow returns and whether more than one run is affected.

Next, find the frozen section. Start at the faucet and work back along the pipe toward where it enters the house, feeling for the coldest stretch, frost on the outside of the pipe, or a visible bulge. The frozen spot is usually near an outside wall, in a crawl space, near a foundation vent, or where the pipe passes through an uninsulated area. Do not assume it is the most exposed-looking section. Feel along the whole run if you can reach it.

Thaw with gentle, steady heat. A hair dryer on a medium setting, moved slowly back and forth along the pipe, is the classic tool for a reason: it is controllable and it cannot overheat one spot the way an open flame can. Start thawing at the faucet end and work back toward the frozen section, so melting water can escape through the open tap instead of building pressure behind the remaining ice. Heating pads wrapped around the pipe, towels soaked in hot water and wrung out, and a space heater aimed at the area from a safe distance all work on the same principle: slow, even warmth.

Never use a blowtorch, a heat gun on high, or an open flame on a frozen pipe. Besides the fire risk in wall cavities and near insulation, sudden intense heat can crack a pipe, damage solder joints, and turn a thaw into a burst. If the frozen section is inside a wall and you cannot reach it, turn up the heat in the house, open the wall cavity if you can do it safely (for example, by removing an access panel), and give it time. A pipe thawing slowly behind a wall is frustrating, but it is not an emergency until it leaks. Check the area regularly as it thaws, because a pipe that froze hard may have cracked, and the leak only shows up once the ice melts and water flows again.

Know when to stop and call a plumber. If you cannot find the frozen section, if the pipe is inside a wall you cannot access, if you see a bulge or a crack, or if flow does not return after a reasonable thawing effort, stop. A plumber has thawing equipment and, more importantly, can find and repair a split in the same visit instead of you discovering it as a flood hours later. And if you thaw a pipe and then find water where it should not be, shut off the main valve and call. That is the moment the job stops being a thaw and starts being a repair.

A burst pipe is loud, messy, and stressful, but the response is a short sequence, and doing it in order keeps a bad morning from becoming a bad month. Shut off the main water valve first. Do not start mopping while water is still pouring in. Do not hunt for the break before the water is off. Valve first, everything else second. If water is near electrical outlets, the breaker panel, or appliances, do not wade in to reach the valve. Cut power to the affected area from a dry, safe location if you can, and stay out of standing water near electricity.

Once the water is off, open faucets at the lowest level of the house to drain the remaining water out of the system, and open a faucet or two upstairs to let air in so the lines drain properly. Move furniture, rugs, electronics, and anything you care about out of the wet area. Lift curtains and cushions off the floor. If water has reached carpet, pull back a corner if you can and get air moving, but do not tear out flooring or cut into walls before someone has documented the damage.

Take photographs before you clean anything up. Photograph the break, the water, the affected rooms, and the belongings that got wet, with wide shots for context and close shots for detail. Your insurer will want this record, and it is far easier to capture it now than to reconstruct it later. Then call a plumber and your insurer, in that order if water is still a problem, or in parallel if you have two people on the job. If you have dealt with a burst before, you know the drill from what to do in the first hour after a burst pipe. The throughline is the same: stop the water, make the area safe, document everything, then get professional help for the drying, because water trapped in walls and under floors keeps damaging long after the visible puddle is gone.

A note on drying, because it is where people underinvest. A wet room that looks dry on the surface can still hold moisture inside drywall, under flooring, and in insulation. Fans and open windows help a shallow spill on a hard floor, but they do not dry a wall cavity. Professional drying uses dehumidifiers and moisture meters and takes days, not hours, and that is normal. Rushing this stage is how a burst pipe turns into a mold problem a month later, which is why professional water damage help exists as a separate trade from the plumbing repair itself. Fix the pipe, then dry the house properly, in that order.

Almost every freeze failure I hear about comes down to one of a handful of mistakes, and all of them are avoidable. The first is leaving a garden hose connected all winter. It is a small job, it takes two minutes, and skipping it defeats frost-free faucets entirely. The second is shutting off heat in an unused part of the house, or setting the thermostat far back during a cold snap to save on heating. The saving is small and the risk is not.

The third is insulating the easy pipes and ignoring the hard ones. Foam sleeves on basement runs are great, but the pipe that bursts is usually the one you could not see, in the wall behind the kitchen sink or above the garage. Sealing drafts around that wall and opening the cabinet doors matters more for those runs than any sleeve you can buy. The fourth is thawing with too much heat, too fast, which cracks pipes and starts fires. Gentle and patient beats fast and dramatic every time.

The fifth is assuming a freeze cannot happen where you live. Warmer states get caught worst, because houses there often have pipes in attics, outside walls, and uninsulated crawl spaces that would never pass muster in a cold climate, and homeowners have no freeze routine at all. Plumbing crews across Texas will tell you the same story after every rare deep freeze: the damage concentrates in homes that were never built or prepared for sustained cold. If your area freezes even a few nights a year, you need a freeze routine. A handful of nights is all it takes.

The last mistake is treating a frozen pipe as a one-off. If a run froze once, it will freeze again in the next hard cold, probably in the same spot, unless something changes. After the thaw, fix the cause: add insulation, seal the draft, reroute the exposure if a remodel ever opens that wall, or at minimum write down which faucet to drip and which cabinet to open so the next freeze is a routine instead of a surprise. A house that has frozen once is a house that has told you exactly where its weak point is. Listen to it.

If you are unsure which runs in your home are vulnerable, or you have a freeze-prone spot that keeps coming back, that is worth a conversation with a local plumbing professional before the next cold snap, not during it. A short visit to map the risky runs and insulate what can be reached is a quiet job on a calm day. The alternative is a loud job on a freezing night, and nobody prefers that version.