What to do before a cold snap, how to leave the house safely in winter, and how to thaw a frozen pipe without breaking it.
Water expands as it freezes. When ice forms inside a pipe, the pressure has nowhere to go, so it pushes on the pipe, the joints and the glass of the water meter until the weakest point cracks. That is why bursts tend to happen not on the first freezing day but when sub-zero weather lasts several days, and overnight when water sits still for hours. Two facts underlie every prevention tip: moving water is much harder to freeze, and the spots hit directly by wind freeze first.
Before winter, walk around your home and look for pipes exposed to cold air. In apartments, the usual suspects are meter boxes along open corridors and the washing machine tap on a balcony against an outer wall. In houses, garden taps, exposed outdoor pipes and the boiler room are most at risk. The older the building, the more likely the insulation has worn out or gone missing, so open things up and check with your own eyes.
Pack the meter box tightly with old clothes or ready-made insulation and tape over gaps in the lid so cold air cannot get in. Always use dry material, because damp fabric simply freezes solid. Wrap exposed pipes in foam sleeves or insulation and keep balcony windows shut. For taps you do not use in winter, such as a garden tap, the surest step is to shut them off and drain the remaining water.
On nights when the temperature drops sharply, or when you will be away for a few days, leave a tap open to a thin trickle. Many guides suggest turning it toward the hot side, because the pipes running to the boiler freeze easily. The water may feel wasted, but it costs far less than a burst pipe. Do not switch the boiler off; use its away or frost protection setting instead. If you unplug it completely, its built-in frost protection cannot work either.
If you open a tap and nothing comes out, or only a thin stream, something is frozen. If only the cold or only the hot side fails, the cause is probably that line or the boiler side. If no tap in the home works, suspect the meter or the pipe outside. If the meter glass is cracked or bulging, it is already damaged, so do not try to fix it yourself and report it first. A section of pipe with frost on the outside, or one that feels unusually cold to the touch, is likely where the ice is.
The rule is to thaw slowly. First open the tap so melted water has a way out, then warm the pipe starting from the end nearest the tap. Wrapping it in a towel soaked in lukewarm water or using the warm setting of a hair dryer are safe choices. Pouring boiling water straight on can crack the pipe or meter through sudden temperature change, and using a torch or any open flame is a fire risk and must never be done.
If a pipe is leaking or the meter is broken, first close the main water valve in your home so the water stops spreading. If water is running toward sockets or appliances there is a risk of electric shock, so switch off the breaker before going near. Report a broken meter to your local water authority, which will explain how it gets replaced, and tell the building management office if you live in an apartment. Who pays for the replacement varies by area, so check the official guidance. If water has leaked to the flat below, photos will help with whatever follows.
Most freezing accidents start with a handful of mistakes. People often open the meter box to check it and forget to put the insulation back, or leave damp insulation in place. Running the washing machine in sub-zero weather can leave water in the drain hose that freezes and causes a backflow, so it is better to wait during a cold snap. And if the conditions stay the same, a thawed pipe will freeze again, so once it is thawed, fix the lack of insulation that caused it.
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