Frozen Pipes in Iowa: How to Prevent Them and How to Thaw Them Safely

When the forecast says -10°F for three days straight, my phone starts ringing nonstop. The calls aren’t usually emergencies on day one. They start coming in on day three — when the freeze has finally crept deep enough into walls and crawlspaces to lock up a pipe somebody depends on.

Here’s what every Iowa homeowner should know before the next cold snap.

Why Iowa Pipes Freeze

Iowa is in the worst combination zone for frozen pipes. We’re cold enough to get genuinely dangerous lows (-15°F to -25°F most winters, with stretches of multi-day deep freezes), AND a lot of our housing stock has uninsulated bays, exterior-wall plumbing, vented crawlspaces, and garage-supplied hose bibbs.

Three things cause pipe freezes in this region:

1. Sub-zero stretches. Anything below -5°F for more than 24 hours starts pushing the freeze line deep into wall cavities. A pipe that’s been fine for 20 years can freeze the first time we get a -20°F night.
2. Poorly insulated exterior walls. Common in older homes (anything pre-1980) and weirdly common in 1990s-2000s production builds that cheaped out on exterior wall insulation behind kitchen and bathroom plumbing.
3. Garage water lines. A huge issue in slab-on-grade homes in Ankeny, Waukee, Bondurant, and parts of West Des Moines. The water line to the laundry or to an outdoor spigot runs through the garage ceiling. Garage doors get left open. Freeze hits. Line locks up. We see it every single winter.

Prevention Checklist

Knock these out in October and you’ll sleep through the first cold snap without worrying.

• Disconnect and drain hose bibbs. Pull the hose off every outdoor spigot, open the spigot to drain any standing water, close the interior shutoff if your line has one. Frost-free bibbs are not bulletproof — they fail when a hose holds water against them.
• Insulate exposed lines. Foam sleeve insulation costs about $1 a foot at the hardware store. Wrap any copper or PEX that’s exposed in the basement, crawlspace, or garage. Pay special attention to the run between the meter and where it disappears into the wall.
• Open cabinet doors during cold snaps. Under-sink plumbing on exterior walls (most kitchen sinks) gets isolated from the room’s warm air by the cabinet doors. Open them when temps drop below 5°F. Pull anything out from under the sink so air can circulate.
• Drip the faucets. Pencil-thick stream on the faucet farthest from the main water shutoff during sub-zero nights. Both hot and cold. Moving water doesn’t freeze. Costs you a few cents on the water bill. Cheap insurance.
• Keep the garage door closed. Especially overnight. Especially if the garage has a water line in the ceiling. I cannot tell you how many garage door openers we’ve watched stay open for 6 hours because somebody hit the button by accident — and then we’re cutting drywall.
• Set the thermostat to at least 55°F when you’re away. If you’re heading to a warmer state for a week in February, do not drop it below 55°F. Saving $40 on a heating bill isn’t worth a $4,000 burst pipe claim.
• Know where your main shutoff is. Find it now. Test it works. Tell every adult in the house where it is. When water is shooting out of a wall at 3 AM is the worst possible time to start hunting for the valve.

Safe Thawing — What Works and What’s Dangerous

If you turn on a faucet and only a trickle comes out (or nothing at all), and it’s below freezing outside, you’ve got a frozen line. Here’s what to do:

Step 1: Keep the faucet OPEN. As ice melts, you want a path for the water to escape. A closed faucet with a thawing pipe is pressure building up behind the ice plug. That’s how lines burst.

Step 2: Find the frozen section. Usually it’s where the pipe runs through an unheated space — exterior wall, garage ceiling, crawlspace. Feel along accessible sections. Frozen pipe is dramatically colder than the surrounding pipe.

Step 3: Apply heat from the faucet end, working back toward the cold spot.

Methods that work:

• Hair dryer. Keep it moving. Hold it 6 inches from the pipe. Patience.
• Heat tape. Wrap the affected section, plug it in. UL-listed pipe heat tape, not the kind you use for roofs.
• Heat lamp or work light. Set it 12+ inches from the pipe. Walk back and check every 10 minutes. Do not point it at framing or insulation.
• Towels soaked in hot water. Wrap them around accessible pipe. Re-soak as they cool. Slow but safe.
• Portable electric space heater. Aimed at the wall cavity, NOT at framing. Use only if the area is clear.

Methods that will set your house on fire (NEVER do these):

• Propane torch
• MAPP gas torch
• Lighters or candles
• Any open flame, anywhere, ever

Thawing a pipe with an open flame is a well-known way houses catch fire during cold snaps. The flame ignites dust and insulation in the wall cavity, you can’t see it, you walk away, and 4 hours later the fire department is at your house. Just don’t.

Danger Signs That Mean Call Us NOW

If any of these are happening, the pipe has likely already burst behind the wall and is leaking. Don’t try to thaw it yourself.

• Any wet spot on a wall, ceiling, or floor near plumbing. Even a small one.
• Sudden drop in water pressure throughout the house. The water is going somewhere — usually behind a wall.
• Any noise from the wall — a knock, a pop, a hiss, or a hammering. A pipe under pressure with a crack will hammer.
• Smell of mildew or wet drywall. You’ve had a slow leak for a while.

In any of these cases: shut off the main, then call (515) 494-5483. We’re 24/7 for burst pipe emergencies — here’s what to do in the first five minutes, and what our 24/7 emergency service covers.

Why Frozen Pipes Burst

Quick physics for the curious: water expands by about 9% when it freezes. In a sealed pipe, that expansion has to go somewhere. As ice forms, it pushes water ahead of it. That pressure builds far beyond what the pipe was made to hold until something gives.

The interesting thing is the pipe usually doesn’t burst at the ice plug. It bursts somewhere downstream where water pressure has nowhere to go. So a freeze in your crawlspace can crack a fitting in the upstairs bathroom. That’s why turning the faucet OFF during a freeze is dangerous — you’re sealing the system and giving the pressure nowhere to escape.

Post-Thaw Inspection

After the freeze breaks and temps come back up:

• Walk every plumbing fixture. Run hot and cold for 30 seconds. Check the cabinet underneath for drips.
• Check the basement ceiling. Look for water stains or fresh drips along any exposed plumbing.
• Look at every joint and fitting in the exposed plumbing. Especially soldered copper joints — they’re the weakest points. Hairline cracks may not leak under low pressure but will under full city pressure.
• Listen. Stand still in the basement after everyone goes to bed. A running toilet or wall leak is loudest when the house is quiet.
• Watch the water bill. A 20%+ jump month-over-month with no lifestyle change means a leak.

The freeze that you thought you got away with is the one that costs you $8,000 in remediation three weeks later when you finally notice the basement ceiling sagging. Don’t skip the post-freeze walkthrough.

If you find anything you’re not sure about, call (515) 494-5483 — we’d rather come look than have you find out the hard way in March. Hidden leaks are exactly what our leak detection and repair service is for.