A burst pipe from a freeze is one of the most expensive plumbing failures you can have — water damage from a single overnight freeze can run $5,000-$50,000 and take weeks to clean up. The good news is that almost every freeze-related burst is preventable. This is a practical checklist of what works and what doesn’t, based on the calls we take across eastern Massachusetts every January and February.
Why Pipes Burst
Pipes don’t burst because the ice expands inside them — that’s the common misconception. Pipes burst because as ice forms in one section of a pipe, water pressure builds up between the ice and the closed faucet downstream. The pressure has nowhere to go and it bursts the pipe at the weakest point — often in a wall, a basement ceiling, or the attic, far from the actual frozen section. That’s why preventing freezing is more important than preventing burst — once you have a freeze, the burst is often inevitable somewhere.
The Day-Before Checklist
When the forecast shows overnight lows below 15°F, especially with wind, run through these:
- Open cabinet doors on kitchen and bathroom sinks against exterior walls. Lets warm room air reach the supply lines.
- Drip the cold water on faucets that supply pipes running through unheated spaces. A pencil-lead-thick stream is enough to keep water moving and prevent freezing.
- Disconnect and drain garden hoses if you haven’t already. The exterior hose bib is the most common single freeze point in a Massachusetts home.
- Heat tape any pipes you’ve had freeze in past winters. Plug them in. Check that they’re working.
- Set the heat to 60°F minimum overnight, even if you’re traveling. The savings from turning the heat lower aren’t worth the freeze risk.
- Find your main water shutoff and make sure it works — turn it off and back on once. If it doesn’t budge, call us before the cold snap, not during.
The Most Vulnerable Spots in MA Houses
Across the homes we work in, the freeze-prone locations follow a pattern: pipes running through unheated attics or crawlspaces; pipes in exterior walls (especially older two-families and Victorians); pipes in basement areas near foundation cracks or open vents; the pipes running to outdoor hose bibs; pipes in garages or attached porches; and the supply lines to laundry rooms in semi-conditioned basements. If you’ve had a freeze in the past, that location is more vulnerable than the rest of the house — heat tape it, insulate it, or rerun it during your next remodel.
If Pipes Have Already Frozen
If a faucet won’t run on a cold morning but other faucets in the house work, you have a freeze somewhere on that supply line. Don’t panic — frozen pipes don’t always burst. Here’s what to do: Turn on the affected faucet (open both hot and cold). This relieves pressure as the ice thaws. Locate the freeze. Check accessible pipes upstream of the faucet — often you can find a section that feels colder than the rest. Apply gentle heat. A hair dryer, heat lamp, or heating pad on the frozen section, working from the faucet toward the freeze. Never use an open flame on pipes — risks fire and damage to the pipe. If you can’t find or reach the freeze, or if you notice any moisture or hissing — call us immediately. We dispatch 24/7 for active freezes.
If a Pipe Has Burst
A burst pipe is an emergency. Sequence: Shut off the main water supply (this is why it matters that you know where it is). Open all faucets to drain the system and reduce remaining pressure. Turn off electricity to the affected area if water is near outlets, light fixtures, or electrical panels. Call us at (781) 242-2386 — we have 24/7 emergency dispatch for burst pipes across all 23 of our service-area towns. Document the damage with photos for your insurance claim.
Preventive Investments Worth Making
If you’ve had multiple freezes in the same spot, the long-term fix is usually one of: rerouting the pipe through conditioned space (most reliable, also the most expensive), foam insulation on the pipe with permanent heat tape (mid-cost, reliable if maintained), or replacing the pipe with PEX-A which tolerates freezing better than copper without bursting (sometimes the most cost-effective). Call us for a quote once the cold snap passes and we can walk through any of these.
If your pipes are frozen right now, or if you’ve had repeat freezes in past winters, call (781) 242-2386. We dispatch 24/7 across Winchester, Arlington, Medford, Lexington, Cambridge, Belmont, Burlington, Newton, Woburn, and 14 other towns.
