How to Prevent Frozen Pipes and What to Do If One Freezes
Prevent frozen pipes by draining outdoor water before the first freeze, then protecting pipes in unheated and exterior-wall spaces before deep cold. Keep the thermostat steady day and night, open sink cabinets on exterior walls, and let a faucet on exposed pipe drip. If a pipe freezes, keep the faucet open and warm it with a hair dryer or heating pad, never an open flame. HomeGuard Weather is a pre-launch iPhone app with no hardware, planned at $59.99/year or $9.99/month, that turns a deep-cold forecast into that checklist.
Which pipes freeze first
Pipes in heated interior walls rarely freeze. The ones that do are usually in a few predictable places, so start there before deep cold.
| Where | Why it is at risk | What to do before deep cold |
|---|---|---|
| Outdoor faucets and hoses | Water sits outside the heated house, and an attached hose keeps it from draining. | Disconnect and drain hoses, close the indoor shutoff for each outdoor faucet if you have one, and leave the outside faucet open to drain. |
| Sprinkler and pool supply lines | Lines run shallow and outdoors. | Drain or winterize them following the installer's or manufacturer's directions before the first hard freeze. |
| Unheated garage | Supply lines often run along garage walls with little heat. | Keep garage doors closed when water lines run through the garage. |
| Crawl spaces, attics, and unheated basements | Cold air and wind reach exposed pipe with no insulation. | Insulate exposed pipe and close gaps that let cold air blow across it. |
| Sinks on exterior walls | Closed cabinet doors keep household heat away from the pipes. | Open kitchen and bathroom cabinet doors on very cold nights, and move cleaners out of children's reach. |
| Where the water line enters the house | The service line comes through the foundation near cold soil and air. | Check this spot first if a faucet slows to a trickle in cold weather. |
The frozen-pipe checklist for the night before deep cold
- Outdoor water: hoses off, drained, and stored. See when to disconnect garden hoses before a freeze.
- Thermostat: keep the same setting day and night. A lower overnight setting saves a little energy but raises the risk in the coldest hours.
- Cabinet doors: open sink cabinets on exterior walls so warm air reaches the plumbing.
- Drip a faucet: in very cold weather, let cold water drip from a faucet served by exposed pipe. Even a trickle helps.
- Garage: keep the doors closed if water lines run through it.
- Main water shutoff: find it now and make sure it turns, so you are not searching for it if a pipe bursts.
- Leaving home: keep the heat on and set no lower than 55°F, and ask someone to check the house if the cold lasts. See what temperature to set your thermostat when away.
Print the general Weather-Ready Home Checklist for a reusable home-care list. If the cold comes with a storm that could knock out power, print the Storm Power Outage Home Checklist PDF too, and browse the full printable checklist library. For a one-page list to tick off, print the first freeze home checklist. If a storm takes the power and the furnace with it, see winter power outage home prep.
At what temperature do pipes freeze?
Water freezes at 32°F, but there is no single outdoor temperature that guarantees a pipe will freeze. Risk depends on how long the cold lasts, wind, insulation, where the pipe runs, and whether water is moving through it. An exposed pipe in a drafty crawl space can freeze on a night that leaves an interior pipe untouched.
A practical rule: drain outdoor water before the first freeze, then treat a hard freeze (around 28°F or lower for several hours) or a long stretch of deep cold as the trigger for the indoor steps above. The hard freeze warning checklist covers that second pass.
How to tell if a pipe is frozen
- A faucet gives only a trickle of water, or none, during cold weather.
- Frost is visible on an exposed section of pipe.
- The problem is on a pipe along an exterior wall or near where the water line enters the house.
If one pipe is frozen, check your other faucets. Others may be frozen too.
How to thaw a frozen pipe safely
- Keep the faucet open. As the ice melts, running water helps clear the rest of the pipe.
- Warm the frozen section with an electric heating pad, an electric hair dryer, a portable space heater kept away from anything flammable, or towels soaked in hot water.
- Never use a blowtorch, kerosene or propane heater, charcoal stove, or any other open flame.
- Do not use electrical heat near standing water or on a pipe that is already leaking.
- Keep applying heat until full water pressure returns.
Call a licensed plumber if you cannot find the frozen section, cannot reach it, or cannot thaw it.
If a pipe bursts
- Shut off the main water valve to stop the flow.
- Stay away from water near outlets, panels, appliances, or cords. If water has reached electrical equipment, leave the area and call a qualified electrician or your utility.
- Call a licensed plumber to repair the pipe.
- Take photos of the damage for your records and any insurance claim before you clean up.
Why an app, not another weather alert
The hard part of frozen pipes is timing. A forecast low of 15°F does not tell you that tonight is the night to open the cabinet under the kitchen sink or check the garage door. HomeGuard turns the forecast into the short list of pipe and home-care tasks that matter for your house, before the cold arrives. It is software only, with no sensor, hub, valve, or device install, and it is not a guarantee against frozen pipes.
Getting ready for snow and ice too? See the winter storm home prep guide. Comparing software reminders with sensors or shutoff devices? Read the app vs. sensors and shutoff comparison. For the full launch scope and pricing, see HomeGuard Weather features & pricing.
Sources and further reading
This guide follows the American Red Cross frozen-pipe guidance, the National Weather Service cold-weather alerts, the NWS glossary on freeze and hard freeze, and IBHS Winter Weather Ready guidance.
FAQ
At what temperature do pipes freeze?
There is no single outdoor temperature that guarantees a pipe will freeze. Water freezes at 32°F, but risk depends on how long the cold lasts, wind, insulation, where the pipe runs, and whether water is moving through it. Outdoor faucets, sprinkler lines, unheated garages, crawl spaces, and sinks on exterior walls are the usual trouble spots.
Should I let my faucets drip to prevent frozen pipes?
In very cold weather, yes. Let cold water drip from a faucet served by exposed pipe. Even a trickle keeps water moving and helps prevent freezing. Pair it with a steady thermostat and open cabinet doors on exterior walls.
How do I thaw a frozen pipe?
Keep the faucet open and warm the frozen section with an electric heating pad, an electric hair dryer, a portable space heater kept away from anything flammable, or towels soaked in hot water. Never use a blowtorch, kerosene or propane heater, charcoal stove, or other open flame. Call a licensed plumber if you cannot find, reach, or thaw the frozen section.
What should I do if a pipe bursts?
Shut off the main water valve, stay away from water near outlets, panels, appliances, or cords, and call a licensed plumber. If water has reached electrical equipment, leave the area and call a qualified electrician or your utility. Take photos of the damage before you clean up.
What temperature should I leave the heat at when I am away in winter?
Keep the heat on and set no lower than 55°F, and ask someone to check the house during a long cold stretch.
Is HomeGuard Weather available in the App Store?
Not yet. HomeGuard Weather is pre-launch and collecting early-access interest for the iPhone app. Planned pricing is $59.99/year or $9.99/month.