Short answer
A winter plumbing checklist starts before the cold: insulate and seal exposed pipes, disconnect and drain outdoor hoses, know where your main water shutoff is and keep the heat on. If a pipe freezes, shut off the water, then thaw it slowly with a hair dryer or warm towels and never an open flame. Septic owners should keep snow cover, keep vehicles off and keep using water.
If you are preparing plumbing for winter, the goal is simple: keep water from freezing in pipes you can reach and in the buried parts you cannot. This guide is a checklist for homeowners in the US and Canada. It covers how to prevent frozen pipes, what to do if one freezes, winter septic tank care and the drains and sump pumps people forget. Where advice differs between sources, we say so.
It is a general guide, not a substitute for your plumber, your water utility or your local rules. Climate, pipe layout and home age all matter.
Winter plumbing checklist: pipes and exposure
Pipes freeze where cold air reaches them. These steps are drawn from Arlington County, Virginia's emergency management office, the City of Vancouver, Washington and Genoa Charter Township, Michigan.
- Insulate exposed pipes in crawlspaces, basements, garages, attics and along outer walls. Arlington suggests wrapping pipes with insulation if they are exposed to cold air.
- Seal cold air sources, such as gaps near pipes, drafty windows and doors, and uninsulated walls and attics. Vancouver also advises sealing gaps that let cold air reach pipes.
- Open cabinet doors under kitchen and bathroom sinks during cold weather so warm room air reaches the pipes.
- Let a faucet trickle in the coldest weather. Arlington suggests the faucet farthest from your main valve. Vancouver suggests an indoor faucet on an exterior wall at night.
- Find your main water shutoff and confirm it works before you need it.
- Ask a plumber to look at any pipe that froze before. A pipe that froze once is a candidate for more insulation or a different route, and a plumber can advise.
Outdoor spigots and hoses
- Disconnect garden hoses and drain them. The City of Vancouver advises disconnecting hoses and shutting off and draining the pipes that lead to outdoor faucets.
- Close the shutoff valve to each outdoor faucet if there is one inside the house, and drain the faucet.
- Insulate the faucet and nearby pipe if it stays connected to the water supply.
- Outdoor hydrants on a well or yard line: the University of Nebraska-Lincoln water program advises shutting off outdoor hydrant valves and draining hoses, because ice can rupture pipes. If you have a well, it also names the well pump as the part most at risk in extreme cold and says to insulate an above-ground well house.
Thermostat and heat
Keep the house warm enough that the pipes inside walls stay above freezing. Sources give different numbers. Arlington says to set the thermostat above 55 degrees, especially if you will be away. Genoa Township says to keep it at no lower than 60 degrees Fahrenheit when you are away, and to keep it at a steady temperature day and night because lowering it at night can risk burst pipes. If you are unsure what suits your home, ask your plumber or insurer. In very cold weather, err toward the warmer setting.
Away from home
An empty house is where a frozen pipe does the most damage, because nobody notices the leak.
- Choose one plan: keep the heat on and have someone check the house, or shut off the water and drain the system. Vancouver describes both options.
- If you drain the system, Arlington's steps are to shut off the main valve, open every faucet starting at the top floor, flush toilets and run the washer and dishwasher briefly, and turn off and drain the water heater following the manufacturer's instructions. When refilling, open all faucets first, then open the main valve slowly.
- Call a licensed plumber if you have a boiler or wet heating system, a fire sprinkler system or are unsure. Genoa notes that shutting off the water can deactivate a fire sprinkler system.
- Septic homes: see the septic section below for what to do with a vacant house.
What to do if a pipe freezes
Signs include little or no water from a tap, or a trickle. Genoa suggests confirming the main valve is open first. If it is, a frozen section is likely. Then follow these steps. They come from Arlington, Genoa Township and the St. John's Regional Fire Department, as published by the City of St. John's.
- Shut off the water. The fire department says not to try to thaw pipes unless the water is shut off, because freezing can cause hidden cracks in pipes or joints.
- Open the faucet on the frozen line so meltwater can flow.
- Apply gentle heat. Genoa lists an electric heating pad, a hair dryer, a space heater kept away from flammable materials or towels soaked in hot water. The fire department mentions an electric hair dryer and certified electric heat tape. Keep electrical devices away from water.
- Start near the faucet and work toward the coldest section. Keep heating until full pressure returns.
- Check other faucets. Genoa says one frozen pipe often means others are frozen too.
- After thawing, turn the water back on slowly and look at pipes and joints for leaks or cracks, as Arlington advises.
Never use open flame
Do not use a blowtorch, kerosene or propane heater, charcoal stove or any open flame on a frozen pipe. The St. John's Regional Fire Department says never to use an open flame such as a blow torch to thaw pipes, because of the fire hazard and the risk of carbon monoxide. Arlington and Genoa say the same.
The fire department says that obtaining the service of a qualified plumber is the safest way to thaw frozen pipes.
When to call a plumber or the utility
- You cannot find the frozen section, it is inside a wall or ceiling or you cannot thaw it (Genoa and Arlington).
- You suspect a burst pipe, or you see water where there should be none. Use your main shutoff.
- The problem may be at the meter. Arlington says not to thaw a frozen meter yourself and to call your water utility.
- Faucets run dry. Vancouver advises leaving them on and calling a plumber, and notes owners are responsible for pipes on their own property.
Winter septic tank care
If your home has a septic system, winter care is mostly about keeping the buried pipes, tank and drain field from freezing. The advice below comes from NDSU Extension in North Dakota, the University of Nebraska-Lincoln water program and the Fraser Valley Regional District in British Columbia.
- Leave snow where it is. NDSU Extension says fresh snow insulates well, accumulations over 12 inches give significant frost protection and snow loses insulating value as it compacts. It also says not to clear snow cover from any part of the system when plowing. The Fraser Valley Regional District adds not to pile large amounts of snow over the drain field, since it can become heavy and cause damage.
- Keep vehicles and heavy traffic off. Compacted snow insulates poorly, so NDSU says not to drive ATVs, snowmobiles or cars over any part of the system and suggests a snow fence or other barrier. The University of Nebraska-Lincoln says compacted soil can force frozen solids into the drain field and cause backups or damage.
- Keep using water. The Fraser Valley Regional District says a rarely used system can freeze and steady inflow helps keep the tank warm. The University of Nebraska-Lincoln suggests spreading warm water use through the day and week, for example the dishwasher in the morning and laundry in the evening, and says never to run water constantly.
- Fix leaks. NDSU says to fix leaky fixtures, such as dripping faucets and leaking toilets, if the house sewer pipe has frozen before. The Fraser Valley Regional District says a small trickle can freeze and eventually freeze the pipe.
- Add insulation where needed. NDSU suggests at least 1 foot of loose insulating material such as hay, straw or bags of leaves over the house sewer pipe where it exits the basement wall if it is shallow, and over the tank if the house is vacant for a week or more. The University of Nebraska-Lincoln suggests spreading 8 to 12 inches of mulch over the tank and other parts the following fall.
- If the house will be empty, the University of Nebraska-Lincoln suggests asking someone to run a load of laundry or dishes daily, or having a certified professional install a tank heater or add insulation for seasonal homes.
- Watch the drain field. NDSU says wet or soggy ground above it can mean effluent is not soaking in properly and a septic installer should examine it.
If you suspect part of the system is frozen, call a septic professional. The sources we opened do not describe do-it-yourself thawing methods for buried septic parts. For signs of trouble, see signs your septic system is failing. For a regular service plan, see septic maintenance near me. For an alarm, see septic alarm troubleshooting. For pumping costs, see septic tank pumping cost.
Drains, frozen drains and sump pumps
- Slow drain in freezing weather. It may be an ordinary clog, but a partly frozen line is possible too, especially a shallow house sewer pipe or one that carries only a small, steady trickle. NDSU Extension says leaky fixtures can contribute to a house sewer pipe freezing. If more than one drain is slow, see main sewer line location and call a plumber. For one slow fixture, see clogged drain: what to try yourself and when to call a plumber.
- Sump pumps. The City of Fargo, North Dakota, as reported by Valley News Live, suggests checking the discharge hose regularly so it does not freeze, since a frozen hose can cause the pump to overheat. It also suggests a larger-diameter PVC pipe at the discharge point, extending four to six feet from the house, to avoid a low spot where water can freeze. Rules on where sump water can go differ by city, so ask your city or county before changing the discharge.
- Know your cleanout. If a drain backs up in the cold, a plumber will want access to the main line. See sewer cleanout and sewer cleaning explained.
What to look up where you live
- Your water utility or city public works: the emergency number, where your meter and street shutoff are and what they will and will not do.
- County health department or environmental health office: for septic questions and sewage backups.
- State or provincial plumbing or contractor licensing board: to confirm a plumber's license.
- Your insurer: what frozen pipe damage and sewer backup coverage includes, and what it expects you to do when you are away.
For Canadian readers. Plumbing and septic systems are regulated by provinces and territories, and municipalities and regional districts set their own rules. Costs are in Canadian dollars. Cold-climate guidance from Canadian sources, such as the Fraser Valley Regional District and the St. John's Regional Fire Department, is cited above.
For plumbing, drain and septic company owners
Winter plumbing and frozen pipe searches spike in cold snaps, and your customers make them before they call anyone. If you want to be the company they find, read emergency plumber marketing and septic business marketing. You can also book a call with LiveLeadsLane. LiveLeadsLane is a marketing practice for contractors, not a directory, and it does not take jobs or refer homeowners.
