How to Prevent Frozen Pipes in Massachusetts (and the Insurance Trap if One Bursts)

To prevent frozen pipes in Massachusetts, keep steady heat on (never below 55°F if you're away), let a thin stream of cold water run from the faucet on your most exposed pipe, open cabinet doors so warm air reaches plumbing on exterior walls, and insulate or heat-tape any pipe in an unheated basement, crawl space, attic, or garage. Do those four things before the temperature drops into the teens and you've handled most of the risk. The part nobody tells you: if a pipe bursts and floods the house, your Massachusetts homeowners policy may only pay out if the home was properly heated and not left unoccupied, so the prevention steps below aren't just about avoiding a mess, they're about keeping your claim valid.

This is the page for the night a polar-vortex forecast lands on New England, or the morning you turn on a faucet and get a sad trickle. Quick, prioritized, and honest about where the real money is at stake. If you want the long-term fix, replacing old galvanized or copper supply lines that keep freezing, that's a separate decision, covered in our Massachusetts repiping guide. This guide is about getting through the cold snap.

How cold does it have to get for pipes to freeze?

Pipes are generally at risk of freezing once the temperature drops to around 20°F, that's the standard freeze-risk figure published by energy.gov. Massachusetts blows past that every January. A typical Worcester or Berkshires cold snap puts overnight lows in the single digits or below zero, and even the coast and Boston metro routinely see teens during an arctic outbreak. So "around 20°F" isn't the rare event here; it's the baseline you should plan around from December through February, with the occasional late-March cold shot too.

How fast does it happen? Hours, not days, when a real cold snap hits, especially for a pipe running through an unheated space or against a poorly insulated exterior wall. The exact freeze-to-burst timeline depends on the pipe's location, material, and insulation, and the precise hour-by-hour figures you'll see on contractor blogs aren't from a primary source, so treat them as rough. The practical takeaway is simpler: when single digits are forecast, do your prevention the evening before, not the morning after.

Whether a given pipe freezes comes down to three things: where it runs, what it's made of, and whether it's insulated. That's why the same arctic night burst a pipe at your neighbor's and spared yours.

Where do pipes freeze in a New England house?

Pipes freeze first in unheated spaces and against poorly insulated exterior walls. The Red Cross names the usual suspects, pipes in basements, crawl spaces, attics, and garages, plus the lines feeding kitchen and bathroom faucets that sit inside cabinets on an exterior wall. In a Massachusetts house, a few of those are worse than the national average.

Our housing stock is old and was not built for sub-zero air. Think about what you're actually heating:

• Unheated stone- or rubble-foundation basements under pre-1900 colonials, where the water main and main shut-off live in the coldest part of the house.
• Exterior-wall plumbing in balloon-framed walls, the open wall cavities in pre-1930s homes let cold air run straight up from the sill to the attic, right past the pipes.
• Knee-wall attics and additions in capes and farmhouses, where a bathroom or kitchen got added over an unheated space decades after the house was built.
• Crawl spaces and unheated mudrooms on the Cape and South Shore, where a thin skirt of insulation is all that stands between the supply line and the wind.

This is also why old Massachusetts homes get scrutinized more by insurers, aging plumbing and thin insulation raise the freeze risk. If you own a pre-1950 house, our guide on insuring older homes in Massachusetts covers how that underwriting works. For now, just know your exterior-wall and unheated-space pipes are the ones to protect first.

The cold-snap prevention checklist (do this tonight)

Work this list top to bottom before the temperature crashes. The first three cost nothing and stop most freezes.

1. Keep steady heat, day and night

Set the thermostat to one temperature and leave it there through the cold spell. The Red Cross is explicit: keep the heat at the same setting day and night, and don't drop it at night to save money during a hard freeze. The few dollars you'd save are not worth a $200 wall repair to chase a frozen pipe. If you're going away, leave the heat on and set no lower than 55°F, that's the Red Cross's minimum for an occupied-but-empty house, and it's also the number that keeps your insurance claim alive (more on that below).

2. Drip the right faucet

Let a thin stream of cold water run from the faucet served by your most exposed pipe, moving water resists freezing even at a trickle. You don't need to drip every tap in the house. Pick the faucet at the far end of an exterior wall, over an unheated basement, or in an addition, wherever the run is longest and coldest. A steady pencil-width stream is plenty. Yes, it costs a little water; it's the cheapest insurance you'll buy all winter.

3. Open cabinet doors on exterior walls

Open the cabinet doors under kitchen and bathroom sinks that sit on an exterior wall, so the room's warm air can reach the plumbing. This is the freeze that catches people off guard, the pipe is technically "inside," but a closed cabinet on a north wall is its own little cold pocket. If you have small kids or pets, move any cleaners out first.

4. Insulate pipes and add heat tape where it counts

Insulate the exposed pipes in unheated spaces, foam pipe sleeves from any hardware store slip on in minutes and cost a few dollars per length. For pipes that have frozen before or run through brutally cold spots, UL-listed heat tape or heat cable is the accepted upgrade; it's an electric cable you wrap or run along the pipe. Use only UL-listed product and follow the instructions, this is the one item on the list with a fire angle, so don't improvise with random cable. Insulating cold-area pipes also trims standby heat loss, so it pays off the rest of the year too.

5. Seal the drafts hitting your pipes

Find where cold outside air is reaching plumbing and block it, rim-joist gaps in the basement, the hole where a pipe penetrates an exterior wall, a drafty crawl-space vent. Caulk or spray foam on a sill-plate gap costs almost nothing and stops the specific draft that's been chilling that one stubborn pipe. In an old balloon-framed house, even stuffing the wall cavity at the sill with insulation helps.

6. Shut off and drain outdoor faucets and sprinkler lines

Before the first hard freeze, disconnect, drain, and store garden hoses; close the inside shut-off valve to each outdoor hose bib and open the outside spigot to drain it. Drain in-ground sprinkler and pool supply lines per the manufacturer's directions. A frozen hose bib can crack and then flood the wall behind it the moment it thaws, and the MA Division of Insurance specifically lists shutting off and covering exterior faucets on its winter-ready prevention list.

Step	Cost	Effort	What it protects
Keep steady heat, 55°F+ if away	Low (heating)	None	Whole house
Drip the most-exposed faucet	A little water	None	One long/cold run
Open exterior-wall cabinet doors	Free	None	Under-sink lines
Foam pipe insulation	$1–$3 per ft	Low	Basement/crawl/attic pipes
UL-listed heat tape	Moderate	Medium	Repeat-freeze pipes
Seal sill/wall drafts	Low (caulk/foam)	Low	Drafty exterior-wall pipes
Drain outdoor faucets & sprinklers	Free	Low	Hose bibs, irrigation

Leaving a Cape house or going away for winter? Winterize it

If you're leaving a Massachusetts house empty in winter, a Cape or Islands second home, a snowbird's place, a property between tenants, you have two real options, and picking wrong is the classic freeze-claim trap.

Option A: keep the heat on, no lower than 55°F. Simplest if someone can check on the house. The risk is a furnace failure or a power outage you don't catch for days, the heat goes off, nobody knows, and pipes freeze in an unmonitored house. If you go this route, have a neighbor or property manager check in during cold snaps, and consider a Wi-Fi thermostat or freeze alarm that texts you when the indoor temperature drops.

Option B: shut off the water and drain the system. The bulletproof move for a house that'll sit empty and unwatched all winter. Shut off the main, open every faucet, drain the water heater and supply lines, and add plumber's antifreeze to the traps so they don't freeze and crack. If you're not confident doing this fully, pay a plumber once in the fall, it's far cheaper than a burst-pipe flood discovered in April. Our Massachusetts water-heater replacement guide is worth a read if your tank is old enough that a freeze could finish it off.

Here's why this decision matters beyond the water: an unoccupied house with the heat left off is exactly the scenario where a freeze claim gets denied. We'll get to that next.

A pipe just froze, what to do right now

If you turn on a faucet and get only a trickle, a pipe is likely frozen, act before it bursts. Here's the order:

1. Keep the faucet open. Leave the tap on. As the ice melts, running water flows through and helps the rest of the ice clear, and an open faucet relieves the pressure that actually causes the pipe to split.
2. Find the frozen section and apply gentle heat. It's usually along an exterior wall or in an unheated space. Warm it with a hair dryer, a heating pad wrapped around the pipe, towels soaked in hot water, or a space heater kept well away from anything flammable. Start near the faucet and work back toward the cold spot.
3. Never use an open flame. Do not thaw a pipe with a blowtorch, a propane or kerosene heater, a charcoal stove, or any open flame. It's a fire risk and it can damage the pipe. This is the single most important "don't" on the page.
4. Know where your main shut-off is, before you need it. If a pipe has already burst, shutting the main is the difference between a wet floor and a flooded house. In most MA homes it's in the basement near where the water enters, often by the meter. Find it now, on a calm day, so you're not hunting for it ankle-deep in water.
5. Check every other faucet. If one pipe froze, others on the same cold run may be next. Open them to check flow.

A burst supply line floods fast, water comes out by the gallon per minute, not the drip, so the shut-off and a quick response matter more than getting the thaw perfect.

Stop and call a licensed plumber if you can't find the frozen section, can't reach it, or can't get it thawed. There's no prize for forcing it. A licensed pro can also tell you whether a pipe that keeps freezing should be rerouted or replaced, and Massachusetts requires plumbing work be done by a licensed plumber, which we explain in our plumbing permits and licensing guide.

If it bursts: water damage and your Massachusetts insurance

A burst-pipe flood is usually covered by Massachusetts homeowners insurance as "sudden and accidental" water damage, but with a catch most homeowners don't know about. According to the Massachusetts Division of Insurance, that coverage typically applies only if the home was properly heated and not left unoccupied. Skip the basics, let the heat fail in an empty house, shut the furnace off while you're away, and the insurer can argue the loss came from neglect, not a sudden accident, and deny the claim.

This is not a fringe scenario. The MA Division of Insurance reported that in 2024, 48.6% of Massachusetts homeowners' insurance claims were for non-flood water losses and freezing-related damage. Nearly half. Frozen and burst pipes are one of the biggest claim categories in the state, which is also why insurers scrutinize these claims hard.

What the general rule means in practice:

• Heated and occupied: a pipe bursts in a normally heated, lived-in house during a cold snap, that's the textbook "sudden and accidental" loss most policies cover.
• Vacant or heat off: a second home or a between-tenants property where the heat was off or had failed unnoticed is the freeze-denial trap. Many policies require you to either maintain a minimum temperature or shut off the water when the home is vacant, and a claim may be denied if you neglected those preventative steps.

The exact required temperature, the precise definition of "unoccupied," and what your specific carrier demands are not universal, they live in your policy. So do the one thing that protects you regardless: call your agent or insurer and confirm your winter requirements before the cold hits. The MA Division of Insurance's Consumer Services Unit can also help, they're reachable at 617-521-7794. (The same advisory pairs frozen pipes with ice dams, the other classic MA winter peril, where roof damage is covered only if sudden, not from years of deferred maintenance.)

For the bigger picture on what a Massachusetts policy covers, how pricing works, and the FAIR Plan, see our Massachusetts home insurance guide. This page sticks to the freeze peril.

Restoration estimates for serious burst-pipe damage routinely run into five figures once you add drywall, flooring, mold remediation, and ruined belongings. That number is exactly why dripping a faucet and holding 55°F is such a good trade.

When should you call a licensed plumber?

Call a licensed plumber when a pipe won't thaw, when one keeps freezing year after year, or when you've had a burst and need it repaired and the damage assessed. A pipe that freezes every winter is telling you something, usually that it's poorly located, uninsulated, or old enough to reroute. A plumber can insulate, reroute, or replace the problem run so you're not dripping that faucet every January for the next decade.

Repeat freezes are also a signal to think about your supply lines as a whole. If your house still has original galvanized steel or thin old copper, a winter of freeze scares is a good prompt to read our repiping guide, which covers the galvanized-vs-copper-vs-PEX decision and what a repipe costs in Massachusetts. Browse vetted Massachusetts plumbers serving your town when you're ready to get it fixed for good rather than patched every cold snap.

FAQ

At what temperature do pipes freeze in Massachusetts? Pipes are generally at risk once temperatures fall to around 20°F, the standard freeze-risk figure from energy.gov. Massachusetts cold snaps routinely drop well below that, into the single digits or below zero, so treat 20°F as the point to have your prevention done, not as a rare event.

Which faucet should I drip, and how much? Drip the cold-water faucet served by your most exposed pipe, the longest run, on an exterior wall, or over an unheated space. A thin, steady stream (about pencil width) is enough; moving water resists freezing. You don't need to drip every faucet in the house.

How do I thaw a frozen pipe safely? Keep the faucet open and apply gentle heat to the frozen section with a hair dryer, heating pad, hot-water-soaked towels, or a space heater kept away from anything flammable, working from the faucet end back toward the cold spot. Never use a blowtorch, propane or kerosene heater, or any open flame. If you can't find, reach, or thaw the pipe, stop and call a licensed plumber.

Does Massachusetts homeowners insurance cover burst-pipe water damage, and can a claim be denied? Usually yes, as "sudden and accidental" damage, but the Massachusetts Division of Insurance notes coverage typically applies only if the home was properly heated and not left unoccupied. A claim can be denied if the heat was off in an empty house or you skipped basic prevention; many policies require you to maintain a minimum temperature or shut off the water when a home is vacant. The exact rule is policy- and carrier-specific, so check your policy and call your agent before a cold snap rather than assuming you're covered.

How do I winterize a second home or Cape house I leave empty all winter? Choose one of two paths: keep the heat on at no lower than 55°F with someone checking on the house (or a freeze alarm watching it), or fully shut off the water, drain the supply lines and water heater and add antifreeze to the traps. The drained option is safest for a house that'll sit unwatched, and a plumber can do it once in the fall.

Are PEX pipes less likely to burst than copper? That's a common claim, but it depends on the install and conditions, and it's not settled enough to state flatly here. If you're weighing pipe materials after a freeze scare, we walk through galvanized, copper, and PEX in the Massachusetts repiping guide, and the honest answer for your house is one to put to your plumber.