Every winter, the Insurance Institute for Business and Home Safety estimates that frozen and burst pipes cause more than $1.8 billion in property damage across the United States. Yet in the vast majority of cases, frozen pipes are entirely preventable. The key is knowing which pipes are at risk, preparing before temperatures drop, and taking simple steps that protect your home all winter long.
Why Frozen Pipes Burst
Water expands when it freezes — by about 9% in volume. When water inside a pipe freezes, it doesn't necessarily burst right at the ice blockage. Instead, pressure builds in the liquid water trapped between the ice blockage and a closed faucet. That pressure has nowhere to go, and eventually the pipe wall gives way — sometimes at a weak point far from where the ice formed.
Copper and PEX pipes fail differently: copper cracks or splits, while PEX tends to expand and may (in some cases) survive a freeze if the pressure isn't too extreme. But neither should be counted on to survive a hard freeze — PEX-A has the best freeze resistance of any pipe type, but even PEX can fail under sustained extreme cold.
Which Pipes Are Most at Risk?
Not all pipes face equal freeze risk. The highest-risk locations are:
- Exterior wall pipes — water supply lines running through walls that face the outdoors, especially on the north-facing side of the house
- Unheated crawl spaces — pipes below the floor in vented crawl spaces drop to outside temperature during cold snaps
- Unheated garages — if your water supply line enters through the garage, or if there's a utility sink in an unheated garage
- Attic pipes — any supply lines running through unconditioned attic space
- Outdoor hose bibs and irrigation systems — the first to freeze; must be winterized
- Basement rim joist area — the band of framing at the top of the foundation wall is a common cold air infiltration point
- Vacation homes and vacant properties — where heat may be turned down or off entirely
The 7 Most Effective Ways to Prevent Frozen Pipes
1. Insulate Exposed Pipes
Foam pipe insulation sleeves are the single most cost-effective freeze prevention tool. They're available at any hardware store for $0.50–$2 per linear foot and slip directly over pipes with no tools required. Cover all pipes in:
- Crawl spaces
- Unheated garages
- Basement rim joist areas
- Any unheated utility spaces
For pipes in exterior walls, more involved work is needed: adding insulation between the pipe and the exterior wall (and accepting that some heat from the interior side reaches the pipe) is the long-term solution. A plumber can also reroute pipes from exterior to interior wall locations in problem areas.
2. Keep Your Thermostat at 55°F Minimum
The American Red Cross recommends keeping thermostats set to at least 55°F even when the house is empty or you're on vacation. This keeps interior temperatures high enough that pipes inside conditioned spaces stay above freezing. Don't be tempted to shut the heat completely off to save money while traveling — a single burst pipe will cost far more than the heating bill savings.
3. Let Faucets Drip on Extremely Cold Nights
When temperatures are forecast to drop below 20°F (-7°C), let faucets served by pipes in at-risk locations drip slightly — just a slow, thin stream. Moving water is significantly harder to freeze than standing water. This is especially important for faucets on exterior walls. The water cost of a slow drip is minimal; the protection it provides can prevent thousands in damage.
4. Open Cabinet Doors Under Sinks on Exterior Walls
Kitchen and bathroom sink cabinets on exterior walls trap cold air against the pipes. On cold nights, open the cabinet doors under these sinks to allow warm room air to circulate around the pipes. It's a simple, free action that can make a meaningful difference.
5. Disconnect and Drain Outdoor Hoses
This step is critical and often overlooked. Even a frost-free hose bib (anti-siphon valve) will freeze if a garden hose is left connected — the hose prevents the sill cock from draining properly. Before first freeze:
- Disconnect all garden hoses from outdoor spigots
- Turn off the interior shut-off valve to outdoor hose bibs (if present)
- Open the exterior spigot to drain residual water
- Leave the exterior spigot slightly open through winter to relieve any remaining pressure
6. Seal Cold Air Entry Points
Cold air infiltration through gaps and cracks in the building envelope is a major factor in pipe freezing. Seal gaps where pipes enter through exterior walls or the foundation with expanding foam or caulk. Check the rim joist area in the basement (the band of wood at the top of the foundation wall) — it's one of the biggest sources of cold air infiltration in most homes and often has gaps where pipes pass through.
7. Install Heat Tape on High-Risk Pipes
Electric heat tape (also called heat cable) wraps around pipes and provides just enough heat to prevent freezing. It's the right solution for pipes that can't practically be insulated or relocated — like a pipe running along an exterior wall in a crawl space. Heat tape costs $30–$100 for a typical installation and plugs into a standard outlet. Self-regulating heat tape is safer and more energy-efficient than the constant-wattage type.
Important: Install heat tape only according to manufacturer instructions. Improperly installed heat tape is a fire hazard. Never overlap heat tape, and never use it on PVC pipes.
Winterizing Before You Leave Town
If you're leaving your home vacant for more than a few days during winter:
- Keep heat at 55°F minimum — never shut it completely off
- Ask a neighbor to check your home periodically if possible
- Consider a full winterization for longer absences: a plumber drains and blows out the entire plumbing system with compressed air and adds antifreeze to drain traps. This is standard practice for vacation homes and seasonal properties.
- Turn off the main water supply if the house will be truly vacant — not just turned down but unmonitored for an extended period. This won't prevent freezing, but it will limit water damage if a pipe does burst.
If Your Pipes Freeze: What to Do
If you turn on a faucet and no water comes out, or only a trickle, a pipe may already be frozen. Act quickly:
- Don't panic — and don't use a torch or open flame to thaw pipes. This is a house fire waiting to happen.
- Locate the frozen section — check the areas described above (exterior walls, crawl spaces, unheated areas).
- Keep the affected faucet open — as the pipe thaws, water needs somewhere to go. Keeping the faucet open also relieves pressure.
- Apply gentle heat: a hair dryer, electric heating pad, or towels soaked in hot water applied to the frozen section. Start from the faucet end and work toward the cold area.
- Check for bursts. Once water flows, watch for leaks. A pipe may have cracked while frozen and only starts leaking when thawed.
- If you can't locate the frozen pipe, or if you suspect a burst, turn off the main water supply immediately and call a licensed emergency plumber.
You can also review our article on what to do in plumbing emergencies for more step-by-step guidance when you have an active pipe failure.
Should You Re-Pipe High-Risk Areas?
If your home has pipes that freeze regularly every winter, the long-term solution is to address the root cause: reroute pipes from exterior walls to interior locations, add proper insulation to crawl spaces, or have a plumber install permanent heat cable solutions. One-time repair costs of $500–$2,000 can eliminate the annual risk of a $5,000–$50,000 burst-pipe disaster.
If you're in a hard-freeze climate, also consider replacing any remaining copper pipes in at-risk locations with PEX-A, which has the best freeze resistance of any pipe material available. See our comparison guide on copper vs. PEX piping for more on why PEX-A handles freeze events better.