Frozen and burst pipes and ice dams are winter losses, and most of them can be prevented by a few checks made in the autumn. This calendar runs from October to March and sets out what to check, when, and what to do if a line freezes or a roof starts to leak.
Key takeaways
- Find the main shut-off in October, before the first cold night, and make sure the household knows where it is.
- Insulate or protect supply lines in unheated spaces such as crawl spaces, garages and rim joists.
- Keep the attic insulated and ventilated, because a warm attic is what melts snow and starts an ice dam.
- During a cold snap, let taps drip on exposed lines and keep the heat on in rooms where pipes run.
- A line that splits usually leaks on the thaw, so check the ceilings and walls after the weather warms.
- Close the main first, then call, and keep the furnace and the power away from any wet area.
October: find the main and check the exposed lines
The first winter task is locating the main shut-off and checking the lines that run through cold spaces. Both are simple checks, and both are easiest before the weather turns.
The main is usually in the basement near the place the service line enters the foundation, though in some houses it sits near the front wall or in a utility room. Find it, turn it once to be sure it works, and mark it so the household can find it in the dark.
Look at the lines that run through the crawl space, the garage, the rim joist and any unheated room. Pipe insulation and heat tape are the usual protections, and a line that is exposed to outside air should be protected before the first freezing night.
November: attic, vents and the roof edge
An ice dam starts with a warm attic, a snow load and a cold eave. The attic and the ventilation are the two things that can be checked before the first heavy snow.
Look into the attic from the hatch. Insulation should be even and not pushed down, and any bath fan or exhaust duct should vent outside rather than into the attic. Air leaks from the living space into the attic warm the roof and melt the snow on it.
Check the eave and the gutters for debris. Ice forms most easily where the eave is cold and the snow above it melts, so keeping the gutters clear and the ventilation open reduces the places where the water can back up.
December: the first cold snap
The first hard freeze is the most common time for a line to freeze. A short plan for that night prevents most of the losses.
Open the cabinet doors under the sink on exterior walls so the warm air reaches the pipes. Let a tap drip on a line that runs through an exposed wall, since moving water is harder to freeze than still water. Keep the thermostat steady, because a house that is allowed to cool in the night is the house that freezes.
Know which room the water would reach first if a line split. The basement, the laundry and the room under a bathroom are the usual places, and a moisture sensor or a bucket near the place is a simple early warning.
January: the thaw and the splits
A frozen line can split when the water starts to move again, which is often after a few warm days. The leak may not show until the morning.
After a cold spell, check the taps for weak flow, the walls for damp patches and the ceilings for stains. A tap that runs weakly or spits air can be a frozen section, and it should be thawed carefully, with heat that is not an open flame.
If a line splits, close the main first. Then call, photograph the damage and move what can be moved. A split line is a plumber's repair, and the water is a restoration job.
February: ice dams and the ceilings
Heavy snow and a few warm days build ice dams. The water that gets under the shingles shows first on the ceiling of the room nearest the outside wall.
Look for icicles along the eave and for a ridge of ice that holds back water on the roof. Do not climb onto an icy roof, and keep clear of the eave when icicles are being knocked down, since they can fall.
A ceiling stain that appears on an upstairs room after a thaw is a sign that water has got under the roof covering. The room should be checked for a drip at a fixture, and the ceiling should be checked for softness.
March: the spring thaw and the ground
The spring thaw brings snowmelt and rain onto ground that is still cold and hard. The water has nowhere to go, and it pushes on the foundation.
Check the grade and the downspouts as the snow melts. Snow that has piled against the house holds water against the wall, and a downspout that discharges at the foundation adds to the pressure.
The sump should be tested before the thaw is at its height. A pump that runs in the first warm rain is the one that is most needed, and its float and discharge should be checked before then.
What to do if a pipe freezes
Close the main if the line is split, keep the flame and the heat away from the wet area, and call a plumber for the repair.
If a line is frozen but not split, the careful steps are to open the tap, warm the line with a hair dryer or heat tape and never use an open flame. A line that has burst should not be warmed until the main is closed and the water is stopped.
Once the line is repaired, the wall or ceiling that it ran through should be checked for damp and the readings taken, as the restoration record requires.
What should the household keep on hand?
A bucket, a towel, a flashlight, the plumber's number and a written note of where the main and the panel are located.
A household that has these items ready can start the first steps in the first minute, rather than searching the house while water spreads. The note of the main and the panel should be kept near the door, and the family should know where it is.
Keep the phone number of the line with the note. The line is answered 24/7, and the first questions are the ones on the checklist, so the call is faster when the answers are already to hand.
What does a frozen line look like before it splits?
A line that has frozen but not split often shows no sign at all, or only a weak flow at the tap. The first sign of trouble is usually the weak tap, and the second is a damp spot later.
A line that is frozen can also show a frost line on the outside of the wall, a bulge in a joint or a cold patch on the pipe where it enters a crawl space. Those are the signs to look for on a cold morning, before the thaw brings the water through.
The household should note any weak tap, any strange sound in a wall and any cold spot near an exterior wall, and call a plumber before the next cold night. A prompt check is cheaper than a split line.
How are ice dam repairs and attic insulation handled?
An ice dam is a roof and attic problem more than a water problem, and the repair is usually a roofer's and an insulation contractor's work. The restoration work dries the ceiling and the wall that the water reached.
The attic should be checked for even insulation, for air leaks from the living space and for ventilation at the eave and the ridge. Those are the factors that make the roof warm enough to melt the snow, and the repair is quoted by the trade that does that work.
The owner should keep the restoration record with the roofer's report, since the insurer may want both. The two documents together show the path of the water from the roof to the room below.
What should a vacant house do in the winter?
A house left empty over the winter needs its water planned, because nobody is there to notice a split line. The heat should stay on at a steady setting, and the water should be shut off where the lines are exposed.
A vacant house with the main closed and the lines drained is less likely to flood than one with the water on and the heat off. Where the water must stay on, a monitor that alarms on water or on a drop in temperature gives early warning.
The owner or a neighbor should check the house on a regular schedule, and the check should include the crawl space, the basement and the ceilings below the bathrooms. A written note of each check is part of the household's record.
Frequently asked questions
At what temperature do pipes freeze?
Pipes in unheated spaces can freeze in hard cold, and the risk rises when the cold lasts for hours. The safest course is to protect the lines before the first hard freeze.
Should I leave the heat on when I go away in winter?
Yes, at a steady setting. A house that is allowed to cool is the one most likely to freeze, and a vacant house should have its water shut off and drained if the lines are exposed.
Can I use a space heater near a pipe?
Only with care. Keep it well away from anything flammable and from wet areas, and never use an open flame to thaw a line.
Is a frozen pipe covered by insurance?
The policy and the insurer decide, and some policies limit cover for freezing when the house was left unheated. Keep the record of the work and ask the insurer in writing.
Does an ice dam always mean a roof problem?
It usually points to the attic and the ventilation as much as the roof. A roofer and the attic insulation are the two things to check together.
What if the thaw brings water into the basement?
Close the main if the source is a line, keep the power off if water is near the panel, and call. Thaw water from outside is traced to its entry point.
Should I call a plumber for a weak tap?
Yes, if the weak flow has no other explanation such as a clogged aerator. A frozen line that is caught early is much easier to deal with than one that has split.
Sources
This guide is general information for Lake County homeowners, not a substitute for an on-site inspection. Prices are estimates. See our disclaimer.