How to Prevent Frozen Pipes (and What to Do If They Freeze Anyway)

A burst pipe dumps 100 to 200 gallons of water per hour into your home. The resulting damage — to floors, walls, ceilings, insulation, and contents — routinely runs $5,000 to $15,000 before accounting for mold remediation, which can add another $3,000 to $10,000 if the water sits for more than 24 to 48 hours. Most of it happens because of one overlooked preparation task done in 20 minutes before winter arrives.

Pipes burst because water expands by about 9% when it freezes, and the pressure that builds when ice blocks a pipe has nowhere to go. The pipe doesn't rupture at the ice — it ruptures downstream from it, where the water pressure spikes.

The Highest-Risk Pipes in Your Home

Not all pipes are equally vulnerable. Focus on:

1. Pipes in exterior walls — especially in bathrooms, kitchens, or laundry rooms on the home's north or west-facing exterior walls. These pipes have only one layer of insulation between them and the cold.

2. Pipes in unheated spaces — crawlspaces, garages, attics, and unfinished basements. Without heat circulation, these zones regularly fall below freezing even when the living space is warm.

3. Outdoor hose bibb pipes — the plumbing feeding your exterior spigots. This is the most commonly burst pipe and the easiest to prevent.

4. Long supply lines to vacation or seasonal homes — unused pipes can freeze completely without any warning signs.

How to Winterize Outdoor Faucets

This is the most important winterization task and takes under 10 minutes per spigot.

If you have frost-free (anti-siphon) sillcocks: These are designed to drain automatically when disconnected — but only if there's no hose attached. A garden hose left connected traps water inside the freeze-proof section. Remove all garden hoses before the first freeze every year, every year, without exception.

If you have standard outdoor spigots (not frost-free):

1. Locate the indoor shutoff valve for each outdoor spigot. These are usually in the basement or utility room, on the pipe that runs to the exterior faucet. If you can't find individual shutoffs, note the location of your main water shutoff.
2. Turn the indoor shutoff valve clockwise to stop water flow to the outdoor pipe.
3. Go outside and open the outdoor spigot to drain any remaining water from the pipe. Leave it open until no more water drips.
4. Install a faucet insulation cover ($3 to $8 at any hardware store) over the spigot for added protection during extreme cold. This is supplemental — the drain step is what matters.

Protecting Pipes in Unheated Spaces

Foam pipe insulation sleeves are inexpensive ($0.50 to $1.50 per linear foot) and easy to install — they split along one side and snap onto the pipe. Prioritize any water lines visible in crawlspaces, garages, or against exterior walls.

Heat cable (heat tape) is the option for pipes in consistently cold zones where insulation alone isn't enough. Thermostatically controlled versions activate only when pipe temperatures drop near freezing, typically 37°F to 38°F (3°C). Follow the manufacturer's installation instructions carefully — heat cable installed incorrectly can be a fire hazard.

Seal air leaks around crawlspace vents, foundation openings, and any penetrations where cold air can draft directly onto pipes. Expanding foam (Great Stuff or equivalent) seals gaps around pipe penetrations in minutes.

During Extreme Cold Events

When temperatures drop significantly below freezing (below -10°F / -23°C), take extra precautions:

• Open cabinet doors under sinks on exterior walls. This lets warm indoor air circulate to the pipes behind them.
• Let faucets drip on pipes that run through cold zones — even a slow drip (2 to 4 drips per minute) keeps water moving enough to prevent freezing.
• Keep interior temperature above 55°F (13°C) even if you're away. Going colder to save on heating costs risks a $10,000+ pipe burst.
• Know where your main water shutoff is before any emergency. If you don't know where it is, see /blog/how-to-find-main-water-shut-off-valve.

If a Pipe Freezes: What to Do

If you turn on a tap and nothing comes out during cold weather, a pipe may already be frozen. Act immediately:

1. Turn off the main water supply as a precaution — if the pipe is already cracked, it will burst when it thaws.
2. Locate the frozen section — check pipes in unheated areas, exterior walls, or near windows. Look for frost on the pipe exterior or feel for unusually cold sections.
3. Thaw slowly with a hair dryer, heat lamp, or electric heating pad. Start from the faucet end and work back toward the frozen section — this allows water to flow out as the ice melts.
4. Never use open flame — a propane torch or heat gun can scorch pipe insulation, damage PVC, or cause a fire inside a wall cavity.
5. Check for leaks throughout the pipe once fully thawed. A cracked pipe may not leak noticeably until water flow is fully restored.

If you can't locate the frozen section or suspect it's inside a wall, call a plumber. A professional can use infrared imaging to find the problem without opening walls unnecessarily.

The One Prevention Task Most New Homeowners Skip

In practice, the most common cause of burst pipes isn't a freak cold snap — it's a garden hose left attached to a frost-free spigot. The design of frost-free faucets assumes an open drain path; the attached hose prevents drainage, the pipe freeze inside the wall, and the homeowner doesn't know until spring.

Removing hoses from all outdoor spigots before the first freeze takes five minutes and prevents what is often a $5,000 to $8,000 insurance claim.

The First-Year Homeowner Maintenance Calendar builds outdoor faucet winterization, pipe inspection, and every other cold-weather preparation task into a single November schedule. It walks through what to do, in what order, so nothing gets missed — including the tasks that experienced homeowners do reflexively but that catch first-timers completely off guard.