What temperature do pipes freeze at?
Water freezes at 32°F, but pipes rarely do at that temperature. The practical threshold for an exposed or poorly insulated run is around 20°F sustained for six hours or more. A protected interior pipe can survive far colder outside air.
The number people quote — 20°F — comes from building research on uninsulated pipe in an unheated space. It is a useful rule of thumb and a poor guarantee. What actually determines whether your pipe freezes is the temperature of the air immediately around it, not the forecast.
In Bend that distinction matters more than it does west of the Cascades. At roughly 3,600 feet the overnight drop is sharper and faster, so a line can go from fine to frozen in a single night rather than over a cold week.
Will pipes burst at 28 degrees?
They can, if the pipe is exposed and the cold holds. At 28°F a hose bib with a garden hose still attached is at real risk within a few hours. A pipe inside a heated wall at the same outside temperature is usually fine.
| Outside temperature | Exposed, uninsulated pipe | Interior heated space |
|---|---|---|
| 32°F to 28°F | At risk after roughly 6–12 hours | Very low risk |
| 27°F to 20°F | At risk within a few hours | Low risk unless heat fails |
| Below 20°F | High risk, hours not days | Risk rises in unheated rooms and crawlspaces |
The same answer applies at 30°F, 27°F and 25°F, which is why the question has no clean threshold. Each drop shortens the time it takes, but the deciding factors are the same three: is the pipe in conditioned air, is it insulated, and is water moving through it.
Why do frozen pipes burst?
Not from ice pushing outward on the pipe wall. The ice forms a plug, then water trapped between that plug and a closed faucet is compressed as the ice keeps growing. Pressure builds until the pipe splits — often some distance from the frozen section.
This is why the split frequently appears in a spot that never froze, and why leaving a tap cracked open helps: it gives the trapped water somewhere to go instead of building pressure.
Where do pipes burst in a Bend home?
The same handful of places every winter: exterior hose bibs, uninsulated crawlspace and garage runs, pipes against exterior walls in unconditioned space, and the long private service run between the meter and the house on larger lots.
- Hose bibs with a garden hose still attached — the hose holds water against the valve and the split happens inside the wall
- Crawlspace and garage runs with no insulation, sitting in outside air
- Pipes in an exterior wall on the north side of the house
- The middle of a long buried run on a big west- or south-side lot, where nobody thinks to look
- Galvanized supply in the pre-1960s core, which has thinned and ruptures at ordinary pressure
Second homes and short-term rentals add a fourth risk that has nothing to do with the pipe: nobody is there. A split in an empty house runs until someone notices, which is why a freeze in an unoccupied property costs so much more than the same failure in an occupied one.
What should I do if my pipes are frozen but nothing has burst?
Call while it is still frozen. That is the cheap window. Leave affected taps cracked open so melt has somewhere to go, and do not use an open flame to thaw anything. A controlled thaw costs a fraction of repairing a rupture.
The reason the timing matters: a frozen pipe does not leak, because the ice is plugging it. If it has already split, the water arrives when it thaws — frequently the next afternoon, often while the house is empty.
If you have no water on a cold morning, that is the signal. We handle frozen pipe repair and controlled thawing across Bend, and we would rather take that call than the one that comes after the thaw.
How do I stop it happening again?
Disconnect and drain garden hoses before the first hard freeze, insulate accessible runs in crawlspaces and garages, and either heat or properly drain a property you leave empty. Most repeat failures are the same hose bib, the second year running.
Setting a thermostat to 45°F is not the same as winterizing. If the property will be empty through a cold snap, the system needs draining properly or the heat needs to stay on — and someone needs to be able to confirm it did.
Last reviewed 2026-09-21 by Bend Plumbing Pros, Bend, OR.