Frozen pipes in Somerville: how to prevent them and what to do if one bursts

Every January cold snap, my phone lights up with the same call: no water in the kitchen, or worse, water pouring through a ceiling. Most Somerville homes were built between 1900 and 1930, and their plumbing was never designed for today's layouts. Here's how I keep pipes safe in the houses I work on, and what to do if one lets go anyway.

Where pipes freeze in older Somerville houses

In triple-deckers and two-families from Winter Hill to Teele Square, frozen pipes show up in the same spots again and again:

• Kitchen and bath sinks on outside walls, especially where a back porch or bay sits right behind the cabinet.
• Basement lines near the sill, where old fieldstone or brick foundations leak cold air.
• Pipes under back porches and in enclosed rear stair halls, which are often unheated.
• Outdoor spigots (hose bibs) that were never shut off from inside.
• Crawl spaces and knee walls under additions and dormers.

Efficient modern furnaces make this worse in one way: they lose less heat into the basement, so the pipes down there stay colder than they used to. The City of Somerville makes the same point in its Preventing Frozen Water Pipes guide.

How to prevent frozen pipes

1. Keep the heat on. If you travel, turn the thermostat down but never off. The City's guide is clear on this.
2. Insulate exposed pipes in basements, crawl spaces and garages with foam pipe insulation, and check that it's still in place each fall.
3. Seal the drafts near pipes. Caulk gaps where pipes, wires and dryer vents pass through walls, but don't block furnace air vents.
4. Open cabinet doors under sinks on outside walls on very cold nights so room heat can reach the pipes.
5. Let a faucet drip. On extremely cold nights, run a thin stream about the width of a pencil, as the City recommends.
6. Shut off and drain outdoor spigots. Before the first freeze, disconnect hoses, close the indoor shutoff for each outside line, drain it, and leave the outside valve slightly open.

If a pipe freezes

A faucet that gives a trickle or nothing at all on a frigid morning usually means a frozen line. Act fast, before the ice splits the pipe:

• Locate the main shutoff first in case the pipe is already cracked.
• Open the faucet the pipe feeds so melting water has somewhere to go.
• Warm the pipe gently with a hair dryer, starting near the faucet and working back toward the cold spot, or wrap it in towels soaked in hot water.
• Never use an open flame or torch. It's a real fire risk in old balloon-framed walls.

If you can't find or reach the frozen section, the City advises calling a licensed plumber to figure out whether the problem is inside your building. If it turns out to be outside, the Somerville Water and Sewer Department may be able to help.

If a pipe bursts

1. Shut off the main water valve right away.
2. Turn off electricity to any area where water is reaching outlets, fixtures or the panel, if you can do it safely.
3. Call a licensed plumber. In Massachusetts, plumbing work has to be done by a master or journeyman plumber licensed by the state board, with a permit from the local plumbing inspector, per the state's plumbers and gas fitters consumer fact sheet.
4. Take photos of the damage before cleanup, then get water out of ceilings, floors and walls fast to limit mold.

Once the plumber is done, I handle the opened walls and ceilings. In pre-1978 houses that means lead-safe work practices, which I explain in my lead paint guide.

Who to call in Somerville

• Somerville 311: dial 311, or 617-666-3311 from outside the city. The City lists it as 24-hour customer service.
• Water and Sewer Department: [email protected], for problems on the City side of your line.
• A licensed plumber for anything inside your building.
• 911 if water is near electrical equipment or you smell gas.

Preventing it next winter

A frozen pipe is a warning that something in the building envelope needs attention. After a freeze, I look for the cause: an uninsulated rim joist, a leaky porch wall, or a supply line running inside an exterior wall that should be rerouted. Air sealing and insulation fix the root problem, and Mass Save often helps pay for it. See my guide to Somerville home rebates and loans for the current programs.

Need a hand?

If a burst pipe opened up your walls, or you want to find the weak spots before the next cold snap, I'm right here in Davis Square. Book a walkthrough and I'll go through your house from basement to attic and give you a clear, prioritized plan.

About the author

Mateus Magno is the founder of Magno & Co — a licensed Massachusetts Construction Supervisor (CS-123658), registered Home Improvement Contractor (HIC #220484) and certified Lead-Safe Renovator Supervisor who has renovated and managed over $3 million in projects across Greater Boston.

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