How to Keep Pipes From Freezing in a Massachusetts Winter

Which pipes freeze first?

Massachusetts winters do not freeze pipes evenly. In the houses we service on the North Shore and around Boston, the failures cluster in the same spots every January:

• Kitchen and bathroom supply lines on exterior walls — especially in additions and remodels where the plumbing was run in an outside wall with little insulation behind it.
• Outdoor hose bibs that were left connected to a hose or not shut off at the interior valve. The freeze happens inside the wall, and the leak appears in spring when the valve is opened.
• Unheated basements, crawlspaces and garages, particularly where a furnace or boiler was upgraded to a sealed unit and the room is no longer warmed by its waste heat.
• Lines near foundation vents, rim joists and bulkhead doors where cold air infiltrates directly onto the pipe.
• Three-season rooms and porches converted to year-round use without rerouting the plumbing.
• Older Boston triple-deckers and multi-families where a vacant unit goes unheated and the risers running through it freeze for everyone.

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What prevention actually works?

1. Insulate exposed pipe. Foam sleeves on every accessible cold and hot line in the basement, crawlspace and garage. It is cheap and it is the single most effective step.
2. Seal the cold air out. Foam or caulk gaps around pipe penetrations, rim joists, sill plates and foundation vents. A pipe in still 40°F air survives; the same pipe in a 15°F draft does not.
3. Shut off and drain outdoor faucets. Disconnect hoses in October, close the interior shut-off, open the outside spigot to drain it. Better still, have frost-free sillcocks installed so the valve seat sits inside the heated wall.
4. Keep the heat on — everywhere. 55°F minimum, including rooms you do not use and vacant units. Open interior doors so warm air reaches the plumbing walls.
5. Open cabinet doors under sinks on exterior walls during cold snaps so room air reaches the pipes.
6. Let a vulnerable faucet trickle overnight when the forecast drops below 10°F. Moving water is much harder to freeze, and the open tap relieves pressure if ice does form.
7. Heat cable on chronic problem lines that cannot be relocated. Use UL-listed self-regulating cable and follow the spacing instructions.
8. Relocate the pipe. The permanent fix for a line that freezes every year is moving it out of the exterior wall. It is a small remodel job, and it ends the annual gamble.

What if you leave the house in winter?

A house left unheated is how a $200 repair becomes a $20,000 insurance claim. If you travel:

• Leave the thermostat at 55°F or higher and have someone check the house every few days.
• Shut off the main water valve and open a low faucet to relieve pressure. If the heat fails, an empty system cannot flood the house.
• For a long absence or a seasonal home, have the plumbing professionally drained and the traps filled with antifreeze — a winterization visit.
• A Wi-Fi thermostat or a low-temperature alarm that texts you is cheap insurance.

How do you thaw a frozen pipe?

If a faucet gives nothing (or a trickle) after a hard freeze, act before the ice expands further:

1. Find the main shut-off and keep it within reach. A pipe that has already split will leak the moment it thaws.
2. Open the affected faucet. Flowing water helps melt ice and relieves pressure.
3. Apply gentle heat to the frozen section, working from the faucet back toward the frozen area: a hair dryer, a heat gun on low, warm towels or a space heater in the room. Never use a torch or open flame — it damages the pipe, ignites framing, and can flash steam inside the pipe.
4. Keep going until full flow returns, then check every joint in the area for drips over the next hour.
5. If the frozen section is inside a wall or you cannot locate it, warm the room and call. We locate and thaw lines without opening more wall than necessary.

What if a pipe has already burst?

Shut the main valve immediately, cut power to any area with standing water, and call (978) 317-1244 — burst-pipe calls are what our 24/7 line is for. Move belongings out of the water, photograph the damage for insurance, and do not run the boiler or water heater if the leak is on their supply. We repair or replace the split section in copper or PEX and, while we are there, tell you honestly whether the rest of that run is at risk.

Precision Plumbing Solutions handles frozen pipe thawing and prevention and pipe repair and repiping across Essex, Middlesex, Suffolk, Norfolk and Plymouth Counties. If the cold snap also knocked out your hot water, our guide to a leaking water heater covers the next steps.