Frozen or burst pipe in Calgary: what to do in the next ten minutes
Written for Calgary homeowners · Last reviewed August 17, 2026
Short answer: If water is coming out, shut off the main first — basement, wall facing the street, usually near the water heater — then cut the power to any wet area, then photograph everything before you touch it. If the pipe is frozen but still holding, open the tap it feeds and warm the pipe from the tap end backwards with a hair dryer. Never a torch, never an open flame.
Two completely different jobs, and mixing them up costs money. Pick your path and ignore the other one until the water is under control.
It's already burst
Water spraying, dripping through a ceiling, or pooling on the floor. Every minute is drywall and flooring. Stopping the flow comes before diagnosing anything.
It's frozen but hasn't burst
No water at one tap, rest of the house fine. You have some time — but not much, because the split usually shows up when it thaws.
Path 1: the pipe has already burst
A half-inch supply line at household pressure moves a startling amount of water. The order below is deliberate.
- Shut off the main. Typically the street-facing basement wall, low down, near the meter and the hot water tank — behind a furnace room partition in an older bungalow, in an unfinished corner of the mechanical room in a 1980s build. Clockwise on a round handle; a quarter turn on a lever. If it's seized, and old gate valves here seize constantly, don't force it into snapping — move on and call.
- Kill the power to anything wet. Live circuits in a flooding basement is the part that can actually hurt you. Breakers off for the affected area. If the panel itself is in the wet zone, don't wade in — call the utility and stay out.
- Open the taps to drain the system. With the main off, open the lowest cold tap in the house and a couple upstairs. That drops the pressure and drains the water still sitting above the break, so it goes down a drain instead of through your ceiling.
- Photograph everything before you clean up. Wide shots of the room, close shots of the split, the water line on the wall, the soaked contents. Adjusters assess what they can see — a floor you've already mopped is worth nothing to your claim.
- Then start extracting water. Wet vac, towels, fans, contents up off the floor. Speed beats thoroughness — standing water wicks into drywall within hours.
Find your main shut-off before you need it. The most useful five minutes a Calgary homeowner can spend in October is walking down to the basement, finding that valve, and cycling it once to confirm it works. A valve you discover is seized while the ceiling is coming down is the difference between a wet floor and a claim.
One thing you cannot do: operate the curb stop at the property line. That valve belongs to The City and neither homeowners nor plumbers may touch it. If your interior main won't close, that's a 311 call alongside the plumber. We map where the ownership line falls separately.
Path 2: frozen, but it hasn't let go yet
The tell is localized: one fixture has no water or a weak dribble, everything else is normal. If nothing in the house has water, the freeze is more likely in the service line from the street — a 311 call, not a hair dryer job. If water goes in fine but won't go out and several fixtures back up at once, that's a frozen sewer line, a different problem with a different fix.
- Open the tap that pipe feeds first. The step people skip, and the one that matters most. Melting ice releases water, and that water needs an exit — an open tap gives it one and relieves the pressure that would otherwise build against the plug. Both hot and cold sides.
- Work from the tap end backwards. Heat closest to the open faucet first, then move gradually toward the frozen section. Heat the middle of the plug and meltwater gets trapped between two blocks of ice — which is exactly how a pipe that would have survived splits instead.
- Use gentle, boring heat. Hair dryer on low, a heat lamp at a safe distance, an electric heating pad wrapped round the pipe, or hot towels re-wrapped as they cool. Keep it moving. It's slow, and slow is correct.
- Warm the room, not just the pipe. Open the cabinet doors under the sink so household heat reaches the pipes behind them. A space heater aimed into the cavity — never left unattended — often does more than the hair dryer.
- Watch the pipe as flow returns. Stay there with a flashlight and look at the whole run. Freeze splits frequently don't leak until the ice clears and pressure comes back. A bulge, a hairline crack or a bead of water at a joint means shut the main off again and go to Path 1.
- Don't assume it's over. A pipe that froze once freezes in the same spot next cold snap, because the reason — missing insulation, an air leak, a run through unheated space — hasn't changed.
Never use an open flame. No propane torch, no blowtorch, no charcoal or kerosene heater. Two reasons, both bad: torching a pipe superheats water inside the ice plug and can rupture the line violently, and a flame inside a wall cavity sits directly against dry framing, old paper-faced insulation and years of dust — in a void you can't see into, can't monitor and can't reach with an extinguisher, so a smouldering start there has time to spread before you know it exists. If a pipe is inaccessible enough that you're reaching for a torch, that's the moment to call instead.
Call a plumber if you can't find the frozen section, if it's inside a wall you'd have to open up, if it's the main service line, or if you think it's already split. Our emergency page has an honest call-now versus call-Monday list.
Not sure if it's frozen, burst, or something else entirely?
Describe what you're seeing and you'll get a straight read on whether this needs someone tonight or whether you can safely thaw it yourself — so you're not paying after-hours rates for a hair dryer job. Same principle as the rest of our Calgary plumbing guides.
Where Calgary pipes actually freeze
Rarely a random pipe in a heated room. The failures cluster where building heat doesn't reach:
- Garage walls. A line run through a shared garage wall to feed a laundry sink, garage tap or the bathroom above. Unheated space, barely insulated cavity.
- The outdoor tap run. The section between the interior shut-off and the hose bib is the classic Calgary burst, and it almost always traces back to a hose left on in the fall. The full winterizing sequence →
- Rim joists and the sill plate area. Where the basement wall meets the floor above. Air leaks there let −30 °C air sit directly against a pipe that thinks it's indoors.
- Crawl spaces and unheated additions. Converted porches and sunrooms over a crawl space with no heat register.
- Vacant or lightly heated homes. Mid-renovation, between tenants, or thermostat turned down while the owners winter somewhere warmer.
So how long does it take for a pipe to freeze?
Nobody can give you a real number, and be sceptical of the pages that do — the internet's favourite "six hours" line gets repeated everywhere with no source behind it. What decides it is exposure, wind, insulation, pipe material and whether water is moving. A well-insulated pipe in a wall cavity can ride out a week at −25 °C; an uninsulated line in a windy crawl space can freeze overnight at −12 °C. A cold snap with bare ground is harder on plumbing than a colder one with a foot of snow, because snow is insulation.
The one number worth acting on comes from The City: keep the home at a minimum of 15 °C to protect the water service line, use only UL-listed heat tape, and disconnect garden hoses before winter. That figure is aimed squarely at empty houses set to 10 °C to save gas, which is where most of this city's frozen service lines come from.
Who pays — and the water meter trap
Same split as any other water service issue. The City owns the pipe from the main to your property line; you own it from there to the house and pay all repair costs on that private portion. That line usually sits only a few metres in from the curb, so a freeze two metres on the wrong side of an invisible boundary is entirely your bill.
The exception homeowners rely on is the water meter, which The City normally owns. Not here: a frozen or damaged water meter is the homeowner's cost, stated plainly in the City's guidance. It catches people out every winter, because the meter sits in the coldest corner of a cold basement — another argument for the 15 °C rule and for leaving the utility room register open.
Source: The City of Calgary — Frozen water lines. The full ownership breakdown, with the 311 script →
What happens when you call 311
If the frozen section looks like the service line into the house — no water anywhere in the building, deep cold snap — report it to 311. As of August 2026, the City describes the process this way:
- The City may send a crew to confirm your service is actually frozen rather than taking the report at face value.
- Response may be delayed during high volumes. In the week a cold snap breaks, everyone calls at once — plan around it.
- You must sign a Work Authorization Form before the City will thaw the private-property portion. Read it first — it sets out what you're agreeing to.
- At-risk properties get letters directing them to the Frozen Pipes Prevention Program. That's not junk mail — it means your address has a history or a known risk factor.
Source: The City of Calgary — Frozen water lines
We're deliberately not telling you what the City charges to thaw a service line, or what happens cost-wise if crews attend and the freeze turns out to be entirely on your side. Neither figure could be verified from a City source, and inventing one would be worse than saying so. Ask 311 when you report it — before the crew is dispatched, not after.
Insurance: the part people find out too late
Alberta burst-pipe claims get disputed over two things: whether the house was being checked, and whether the damage was sudden or the slow result of poor maintenance. An Alberta brokerage states that most insurers require a vacant home to be checked every 24 to 72 hours for burst-pipe damage to be covered, and that clogs and high water pressure are treated as maintenance and likely not covered. It also names the service line endorsement as the add-on covering underground service lines against tree roots, corrosion and shifting earth — coverage plenty of Calgary homeowners assume they already have and don't.
Source: ACERA Insurance — Are burst pipes covered by home insurance in Alberta?
That's one brokerage's description, not a universal rule, and not your policy. Two practical moves: read your own vacancy clause before you travel in January, and if the house will be empty, have a named person physically enter it on a schedule and keep a dated text log. Cheap evidence.
If your first sign of trouble was a water bill that jumped rather than water on the floor, that's a different hunt — start with finding a silent leak. And for what the repair itself runs, our page on Calgary plumber rates is blunt about how little authoritative pricing data exists here.
Questions Calgary homeowners actually ask
One tap has no water but the rest of the house is fine. Is that a frozen pipe?
Almost certainly, yes — if it happened during a cold stretch and nothing else in the house changed. A freeze is local. It plugs the one run of pipe that got cold, so you lose that fixture and nothing else. Very often it's a kitchen sink on an outside wall, a laundry tub in the garage, or a bathroom above an unheated space.
The comparison that tells you it's something else: if every tap in the house is dead in the middle of a cold snap, look at the service line coming in from the street rather than anything inside your walls, and call 311. And if water goes down the drains fine one day and backs up out of the floor drain the next, that's a sewer problem, not a supply problem — two different pipes, two different fixes.
Should I leave a tap dripping when it gets really cold?
It's the standard advice and it does work for the specific pipes you're worried about — a bit of movement in the line makes an ice plug much harder to form, and a dripping tap keeps the pressure down if one does start. If you know which run froze last time, that's the tap to leave running a pencil-thin stream on both hot and cold.
Two honest caveats. It's metered water in Calgary, so leaving every tap in the house running for a week isn't free, and it does nothing for the pipe you didn't think about. The bigger wins are keeping the house at or above the 15 °C the City recommends, opening the cabinet doors under sinks on outside walls, and sealing whatever gap is letting outdoor air onto that pipe in the first place.
The City sent us a letter about frozen pipes. Is that a real thing or junk mail?
It's real. The City sends letters to properties it considers at risk of frozen water service lines, and those letters point you to its Frozen Pipes Prevention Program. Addresses tend to land on that list because of a history of freezing, a shallow service line, or something about the property that makes it more likely.
Worth taking seriously, because the private side of the service line is your bill, not the City's — including a frozen or damaged water meter, which is the one exception people always get wrong. Read the letter, follow the instructions, and if it's a rental or a place you don't live in, make sure whoever is there over the winter knows about the 15 °C minimum.
We're away for six weeks in the winter. What do we actually have to do?
Set the furnace at 15 °C or higher, not 10 °C — the savings on gas are not worth the risk, and 15 °C is the number The City publishes for protecting the service line. Shut off the water at the main and drain the system down if nobody will be in the house at all. Disconnect any garden hose, open the outdoor tap and bleed the line to it. Leave cabinet doors open under sinks on exterior walls.
Then the part people forget: have a real person physically go into the house on a schedule. An Alberta brokerage says most insurers want a vacant home checked every 24 to 72 hours for burst-pipe damage to be covered. That's their description rather than a universal rule, so pull out your own policy and read the vacancy clause before you book the flight. Keep a text log of the visits — it costs nothing and it's exactly the evidence an adjuster asks for.
A pipe burst while we were out. Should I clean up first or call insurance first?
Stop the water first — main shut-off, breakers off for the wet area — then get your phone out and document before you move a thing. Wide shots of the room, close-ups of the split pipe, the water line up the wall, the soaked boxes, the ceiling stain. Then start extracting water, because standing water keeps doing damage while you wait for a call back.
You don't have to choose between mitigating and documenting, and your policy almost certainly requires you to limit further damage. What you must not do is have the basement tidy and the ruined contents at the curb before anyone sees it. Adjusters assess what's in front of them, and photos taken in the first ten minutes are worth more than any description you write later.
Can I thaw it with a propane torch? My neighbour does it every year.
No, and your neighbour has been lucky. Two things go wrong. Superheating water trapped inside an ice plug can rupture the pipe far more violently than the freeze would have, and thawing inside a wall cavity puts an open flame directly against dry framing, old paper-faced insulation and decades of dust, in a void you can't see into and can't reach with an extinguisher. A pipe run inside a wall is surrounded by the most combustible material in your house, and a smouldering start in there can burn unnoticed for a long time before it reaches a room.
Hair dryer, heat lamp, heating pad or hot towels, always with the tap open and always working from the tap end back toward the ice. It's slow and boring, and that's what makes it safe. If the pipe is somewhere you can't reach without opening a wall, that's the point to hand it to someone with a proper thawing setup rather than escalating to fire.