How to Prevent Frozen Pipes in Winter: Complete Guide

A single frozen and burst pipe can flood your home with 250 gallons of water per hour and cause $5,000–$70,000 in damage. The good news: frozen pipes are almost entirely preventable with a few hours of preparation before cold weather arrives. Here is everything you need to know to keep your pipes flowing all winter.

Why Pipes Freeze — and Which Ones Are at Risk

Pipes freeze when the temperature of the water inside drops to 32°F and stays there. The air temperature does not have to reach 32°F for this to happen — pipes in unheated spaces can freeze when outdoor temperatures are in the teens or 20s, even with heated interior air just a wall away.

The highest-risk locations:

• Crawl spaces: Unheated crawlspaces are the most common site of frozen pipes. Cold air circulates freely under the home, and water supply lines running through them are completely exposed.
• Exterior walls: Pipes inside walls adjacent to the outside with inadequate insulation can freeze during sustained cold.
• Garages: Any supply lines feeding a utility sink, ice maker, or outdoor faucet through an attached garage are vulnerable.
• Attic spaces: Less common but some homes route supply lines through attics.
• Outdoor faucets (hose bibs): The most common residential freeze point — often the first to go.
• Under kitchen or bathroom sinks on exterior walls: Cabinet doors block warm air from reaching the pipe — especially an issue for sinks on exterior walls.

Strategy 1: Insulate Vulnerable Pipes

Pipe insulation is the single most effective prevention strategy for non-acute cold. It slows heat loss from the pipe's water to the surrounding cold air, keeping the water above freezing for much longer during temperature dips.

Foam pipe insulation sleeves are inexpensive ($0.50–$2.00 per linear foot) and install in minutes — they split lengthwise, wrap around the pipe, and seal with pipe tape. Most hardware stores carry standard sizes (½", ¾", 1") for common residential pipe diameters.

Where to Insulate

• All water supply lines in crawl spaces — both hot and cold
• Pipes running through or adjacent to attached garage walls
• Any pipes in unheated utility rooms
• The 12–24 inches of pipe just inside the house from an outdoor faucet connection
• Pipes along the rim joist (where floor framing meets foundation wall) — air infiltrates here

Also seal any gaps or cracks in the foundation, sill plate, or crawlspace vents that allow cold air infiltration. Foam sealant and caulk applied to air leaks near pipes reduces the work insulation has to do.

Strategy 2: Install Heat Tape on High-Risk Pipes

Heat tape (also called heat cable) is electrically powered tape that wraps around a pipe and provides low-level warmth, preventing the pipe from dropping to freezing temperature. It is the right tool for pipes that are difficult to insulate adequately or in locations that get sustained extreme cold.

Types of Heat Tape

• Self-regulating heat cable: Automatically adjusts heat output based on temperature — uses less electricity in mild conditions, more when it gets very cold. The best choice for most homeowners. Brands include Frost King and EasyHeat.
• Constant wattage heat cable: Outputs the same heat regardless of temperature. Less efficient but simpler. More common in commercial settings.

Installation Notes

• Follow manufacturer instructions precisely for your pipe type (plastic vs. metal pipes have different installation requirements)
• Do not overlap heat tape on itself — this creates hot spots and is a fire hazard
• Plug in to a GFCI-protected outlet
• Cover heat tape with pipe insulation for maximum efficiency
• Inspect heat tape annually before winter — damaged tape should be replaced, not reused

Strategy 3: Shut Off and Drain Outdoor Faucets

Outdoor faucets (hose bibs) are the most common and preventable freeze point in residential plumbing. Properly shutting them off takes 10 minutes and eliminates a major risk source.

1. Find the interior shutoff valve for each outdoor faucet — typically in the basement or crawlspace, close to where the pipe exits the house
2. Turn the valve clockwise to close
3. Go outside and open the outdoor faucet fully to drain water from the line
4. Leave outdoor faucet slightly open to allow any residual pressure to escape; close once fully drained
5. Disconnect and store all garden hoses — a connected hose traps water in the line and defeats the shutoff

If your home has frost-free hose bibs (the stem is 6–12 inches long), they are designed to drain automatically — but only when hoses are disconnected. Always disconnect hoses before cold weather.

Strategy 4: Keep Indoor Temperature Consistent

Thermostat setbacks save money — but going too low overnight or while away in winter creates pipe risk. General guidance:

• Keep indoor temperature at 55°F or above, even when sleeping or away from home
• Avoid large overnight setbacks (more than 5–8°F) during extended cold snaps
• If you leave for vacation in winter, do not turn the heat below 55°F
• Consider a Wi-Fi thermostat that alerts you if indoor temperature drops unexpectedly

For vacant properties or properties where heating may fail (power outage, furnace malfunction), the safest option is a full winterization with drains — see below.

Strategy 5: Let Faucets Drip During Extreme Cold

When temperatures are forecast to drop very low (teens and below) for extended periods, letting affected faucets drip slightly reduces freeze risk. Moving water requires more energy to freeze than standing water. The continuous movement also relieves pressure buildup that causes burst pipes when ice forms.

How to do it effectively:

• Open the cold water tap to a slow, steady drip — not a full stream, just a trickle
• Focus on faucets served by pipes on exterior walls or in cold spaces
• Both hot and cold lines can freeze — if a pipe on the hot water side runs through a cold space, run a warm trickle
• This uses minimal water (a drip at ¼ gallon per minute for 12 hours = 3 gallons total)

Strategy 6: Open Cabinet Doors Under Sinks

Kitchen and bathroom sinks on exterior walls have pipes that are often separated from the cold exterior by only a thin cabinet panel. During extreme cold, opening the cabinet doors lets warm interior air circulate around the pipes. A simple step that costs nothing.

Move any cleaning products or hazardous materials out of reach before opening — especially if you have children or pets.

Strategy 7: Full Winterization for Vacant Properties

If a property will be vacant for the winter, the most reliable protection is a complete drainage of the plumbing system:

1. Shut off the main water supply
2. Open all faucets to drain the lines — starting at the highest point in the house, working down
3. Flush all toilets to empty tanks and bowls; pour non-toxic antifreeze (RV or plumbing antifreeze, not automotive) into toilet traps and drain traps
4. Drain the water heater
5. Blow out irrigation lines with compressed air if applicable

For complex plumbing systems or if you are unsure, have a plumber perform the winterization. The cost is far less than repairing a burst pipe discovered weeks later.

What to Do If Pipes Freeze Anyway

If you turn on a faucet and get no water (or very little) during cold weather, a pipe may be frozen. Here is what to do:

1. Keep the faucet open. As you thaw the pipe, steam and water need somewhere to go. Open faucet pressure also helps push the ice out.
2. Apply gentle heat. Use a hair dryer on low/medium, a heating pad, or warm (not boiling) towels. Work from the faucet end back toward the frozen section.
3. Never use open flame. Torch lighters, propane torches, and open flames have caused many house fires attempting to thaw pipes. Not worth the risk.
4. Do not force water. If the line is fully blocked with ice, do not try to pump water through — the pressure can burst the pipe.
5. If you cannot locate or reach the frozen section, call a plumber. Pipes inside walls or floors require professional equipment to thaw safely.

Prevention Cost vs. Repair Cost