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Plain-English article
How to Thaw Frozen Pipes in Thornton, CO Without a Burst
Front Range cold snaps can turn a mild afternoon into a hard freeze by morning. If a faucet runs dry or only trickles, ice may be blocking the line. Thawed carefully, the pipe often survives. Rushed or heated badly, it can split or start a fire.
By the Thornton Plumbing Co. team ·
Signs a pipe is frozen
The first clue is a faucet that gives little or no water when the weather is below freezing. If only the cold side is affected, the frozen pipe is probably on the cold line. If nothing flows at any tap, the freeze may be at the main line or the meter.
Look for frost on an exposed pipe, a bulge in a pipe wall or a section that feels icy compared with the rest. Pipes in garages, crawl spaces, exterior walls and unheated basements corners freeze first. A pipe in a cabinet against an outside wall is another common spot.
Sometimes the pipe has already split. Listen for running water behind a wall, and look for wet drywall, a stain on a ceiling or water on the floor. If you see any of that, go straight to the main valve.
Do these things first
Open the faucet that is not flowing, and leave it open. As the ice melts, water and steam need somewhere to go, and an open tap eases pressure that can crack the pipe.
Find the main water shutoff and make sure you can reach it. If you find a split, you will want to close it quickly. In many Thornton houses it sits where the line enters, often in a basement or utility room.
Check the area around the pipe for electrical hazards. Never use a heat source near standing water, and never touch electrical devices with wet hands.
Safe ways to thaw a pipe
Start where the pipe is closest to the faucet and work toward the frozen area. This lets melted water escape. Use a hair dryer on a low setting, a heating pad wrapped around the pipe or towels soaked in hot water. Keep moving the heat along the pipe.
Space heaters can help warm a room or a cabinet, but keep them well away from anything flammable and never leave them unattended. Open cabinet doors under sinks so warm room air reaches the pipes.
Be patient. Thawing can take a half hour or more. When water flows at full strength again, check all the fixtures and look for leaks along the pipe.
Thawing methods compared
Not every heat source is safe. This table sorts them by risk.
| Method | Safety | Notes |
|---|---|---|
| Hair dryer on low | Safe | Work from the faucet toward the frozen section |
| Heating pad or warm towels | Safe | Wrap the pipe and re-wet the towels as they cool |
| Space heater near the area | Use with care | Keep clear of anything flammable and stay in the room |
| Propane torch or open flame | Dangerous | Fire risk and can damage the joint |
What not to do
Do not use an open flame. A propane torch, a lighter or a heat gun at high setting can ignite insulation, scorch wood or overheat a pipe so that the joint fails. Several house fires start this way each winter.
Do not pour boiling water on an exposed pipe, since fast heating can crack a cold pipe. Do not ignore a pipe that has frozen once, either. The ice may have weakened it or cracked a joint that will leak when it thaws.
When the ice sits somewhere you cannot reach, such as behind drywall, leave the wall alone and phone a plumber.
If the pipe has split
Shut off the main valve and open a low tap to empty the lines. Switch off power to the area from a dry spot. Place buckets, move belongings and photograph the damage.
Call the 24/7 line. A plumber will cut out the split section, replace it and check nearby pipe. See burst pipe repair for what to expect, and water damage restoration if walls or floors are wet.
Ask the plumber to look at the cause. A pipe that froze because of missing insulation or a draft needs that fixed, or it will freeze again.
Prevent the next freeze
Insulate exposed pipes in garages, crawl spaces and basements with foam sleeves. Seal gaps where cold air enters near pipes, such as around dryer vents and cable entries. Disconnect hoses from outdoor spigots in autumn.
On very cold nights, open cabinet doors on exterior walls and let a faucet drip. Keep the thermostat at a steady temperature, even if you travel. If you leave for a long time in winter, consider shutting off the main valve and draining the lines.
Know your main valve, and test it twice a year. A valve that will not turn is a problem you want to find before an emergency, and you can call for a replacement of a seized valve. If you also see low pressure in winter, the water line page explains the service line.
After the water returns
Once the flow is back, leave the faucet running at a trickle for a few minutes. Check the pipe and its joints for drips, and look at the walls and ceiling below for new damp patches. A pipe that froze once can freeze again tonight, so add insulation or heat before the next cold evening.
Quick answers
Asked about frozen pipe
Frozen pipes affect water supply, so a faucet gives little or none. Clogs affect drainage, so water will not go down. If it is below freezing and water will not come out, suspect ice.
Not at all. Plenty thaw intact. Still, ice can leave a weak spot, so inspect the pipe once it has thawed.
There is no fixed time. Splits often happen when ice expands, and the leak shows up when it thaws. Thaw it slowly and watch it.
Many policies cover sudden damage from a burst pipe. Review your policy and call your insurer early.
Connected services
Water Damage Restoration
Pump out standing water, dry framing and finishes and rebuild after a leak, freeze or sewage backup. Open page
Water Line Repair & Replacement
Mend or renew the buried pipe between the city's meter and your foundation when it breaks or corrodes. Open page
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