Frozen Pipes: How to Prevent and Thaw Them Safely

A frozen pipe can turn a cold night into a soaked ceiling, a ruined stockroom or a tenant calling you at 6 a.m. The good news is that a handful of simple habits prevent most freezes, and a calm, safe approach handles the rest. This guide covers how to protect pipes in homes, rentals and small business premises, and what to do if one freezes anyway.

Water expands when it freezes. Inside a pipe, that expansion builds pressure, and the weak point is not always where the ice is. A pipe can split quietly overnight and only start leaking when it thaws, often while you are at work or away for the holidays.

December is when this guide matters most. The heating is working hard, people travel, offices close for a week or two, and the first real cold snap often catches buildings unprepared. A little planning now protects your home, your rental units and your business from one of winter's most expensive surprises.

Which pipes are most at risk

Pipes inside warm, heated rooms rarely freeze. The trouble spots are pipes that sit in cold air or run along cold surfaces. Take ten minutes to find yours.

• Unheated spaces: basements, crawl spaces, attics, garages and outbuildings.
• Exterior walls: pipes running along outside walls, especially behind kitchen and bathroom cabinets.
• Outdoor taps and hoses: anything that holds water outside the heated envelope of the building.
• Rarely used rooms: spare bathrooms, storerooms and back offices where the heating is often turned down or off.
• Empty properties: rentals between tenants, holiday homes and closed business premises.

Write the list down. It becomes your cold-weather checklist, and it is useful information to pass on to tenants, staff or a neighbor who checks the property while you are away.

How to prevent frozen pipes

The American Red Cross guidance is refreshingly simple. Most of it costs nothing, and the rest costs very little compared with water damage.

1. Keep the heat steady. Set the thermostat to the same temperature day and night during cold spells, instead of letting the building cool down sharply overnight.
2. Never go too low when away. If you leave the property, keep the heat set no lower than 55°F (about 13°C). In the UK, the usual advice is to keep the heating on low while you are away.
3. Let faucets drip. When temperatures drop hard, let cold water drip from faucets served by exposed pipes. Moving water is much less likely to freeze.
4. Open cabinet doors. Open the doors under kitchen and bathroom sinks so warm room air can reach pipes on outside walls. Move cleaning products out of reach of children and pets first.
5. Insulate pipes in unheated areas. Fit pipe insulation in basements, crawl spaces, attics and garages. Ask a hardware store for the right type and size for your pipes.
6. Deal with outdoor taps. Disconnect and drain hoses, and shut off and drain outdoor taps if your system allows it.
7. Know your shutoff. Make sure everyone who might need it can find and turn the main water shutoff.

Extra steps for rentals and business premises

If you are responsible for property other people use, frozen pipes become a shared problem. A clear plan helps tenants and staff act quickly and protects you from bigger damage.

For landlords

• Send tenants a short winter note before the cold arrives: where the main shutoff is, how to keep the heat steady, when to let a tap drip and who to call in an emergency.
• Check vacant units regularly and keep the heating on low between tenancies.
• Insulate pipes in shared or unheated areas such as basements, garages and utility rooms.
• Keep a log of the checks you make and any problems reported, with dates.

Who is responsible for damage can depend on the lease, the cause and local law. This is general information, not legal or insurance advice, so check your policy and speak with a qualified professional if you are unsure.

For small businesses

• Add pipe protection to your holiday shutdown routine: heating low but on, taps on exposed pipes considered, and cabinet doors open where it is safe.
• Name one person who will check the premises during any closure.
• Store stock, records and equipment off the floor in areas where a leak could reach them.
• Make sure your out-of-hours contact knows where the shutoff is.

How to tell if a pipe is frozen

The most common sign is simple: you turn on a tap and only a trickle comes out, or nothing at all, while other taps work normally. Other clues include frost on a visible pipe, a pipe that feels much colder than the ones around it, or a bulge in a section of pipe.

Before you start, think about where the pipe runs. A frozen pipe you can see and reach, under a sink or along a basement wall, is a reasonable job to tackle yourself. A pipe hidden inside a wall, ceiling or floor is a different matter, because you cannot check it for cracks or apply gentle heat safely. In that case, keep the room warm, open the tap and call a plumber rather than cutting into anything.

If you suspect a frozen pipe, act calmly but promptly. Ice can block the flow for hours and then cause a leak as it melts, especially if the pipe has already cracked.

How to thaw a frozen pipe safely

Safety comes first. Never use an open flame, such as a blowtorch, a gas heater or a candle, to thaw a pipe. It is a serious fire risk and can damage the pipe. Instead, follow these steps.

1. Open the faucet. Open the tap the frozen pipe feeds. As the ice melts, running water helps clear the rest.
2. Find the frozen section. Start with exposed pipes in cold spots, such as under sinks on outside walls or in the basement.
3. Apply gentle heat. Use a hair dryer or warm towels wrapped around the pipe. Start near the tap and work back toward the frozen section.
4. Keep going until flow returns. Continue until water runs at normal pressure.
5. Check for leaks. Look along the pipe and nearby surfaces for drips or damp patches once it is running again.
6. Call a professional when needed. If you cannot find or reach the frozen section, cannot thaw it, or find a leak, call a qualified plumber.

If a pipe bursts

Turn off the main water shutoff straight away. If water is near electrics, stay clear and get professional help. Move valuables and records out of the way, take dated photos of the damage for your insurer and call a plumber. For rentals, let tenants know what is happening and keep a record of every step.

A cold-weather pipe check template

A simple log keeps the at-risk spots in front of you and gives landlords a record of reasonable care. Copy these columns into a spreadsheet and fill in your own spots. The example rows are made up.

Frequently asked questions

The bottom line

Frozen pipes are one of the most preventable winter problems. Keep the heat steady and never below 55°F when you are away, let cold water drip on the coldest nights, open cabinet doors, insulate pipes in cold spaces and know exactly where the main shutoff is.

If a pipe does freeze, open the tap and thaw it gently with a hair dryer or warm towels, never a flame, and call a plumber if you find a leak. Spend twenty minutes on this list today, and you can enjoy the cold weather instead of worrying about it.