Frozen pipes in a Korean home: prevention, first aid, and when to call

Where Korean homes actually freeze

Whether your home freezes has less to do with the outside temperature than with how your building separates heated space from unheated space. Korean apartments are heated by underfloor 온돌 heating, which warms the rooms inside the insulated envelope very effectively — and does nothing at all for anything outside it. Almost every frozen-pipe call we take is a pipe sitting in that unheated gap.

• The balcony washing-machine tap. This is number one by a wide margin. The tap and its short supply line sit on an unheated balcony behind a sliding window, often with a metre of exposed pipe and no insulation at all. It holds standing water, it is thin, and it is the first thing to go.
• Utility room (다용도실) and balcony pipework. If your balcony has not been converted into living space (발코니 확장), it is effectively an outdoor room with a window. Supply lines to the sink, the laundry area or an outdoor tap freeze there long before anything indoors does.
• Corridor-side wall pipes. In older apartments and officetels, some supply lines run inside the wall facing the shared outdoor corridor. That wall is cold on both sides, and the pipe inside it is the one that fails in a long cold snap.
• Outside taps and garden lines. Villas, low-rises and detached houses often have a tap on the outside wall or in the yard, plus the buried line feeding it. Those freeze early and thaw last.
• Water meter boxes (계량기함). The meter sits in a recessed box in the wall or corridor; if the box insulation has gone missing or was never packed, the meter and its connections freeze.

If your balcony has been converted and enclosed, you are in much better shape — the pipework is inside the heated envelope. If it has not, treat the balcony as outdoors when the forecast drops, because that is exactly what it is.

What to do before a cold snap

When the forecast shows below −10°C, an hour of preparation is worth far more than any thawing job afterwards. None of this requires a plumber.

• Leave a thin stream of water running. A trickle roughly the thickness of a pencil lead from the tap furthest along the line keeps water moving so it cannot set. Run it overnight through the coldest part of the night — a few hundred won of water against a burst pipe is not a difficult trade.
• Do not switch the boiler off when you travel — use 외출 (away) mode. Away mode keeps the system circulating just enough to stop the heating pipes freezing. Switching the boiler off entirely, for a week away in January, is the single most common way people come home to a burst pipe.
• Open the cabinet doors under the kitchen and bathroom sinks. It lets warm room air reach the supply lines and traps hidden behind the cabinet, which are otherwise in a cold pocket.
• Insulate exposed pipe. Foam pipe insulation (보온재) is sold at any hardware shop (철물점) and at the large DIY stores, costs very little, and slides straight over a bare pipe. Wrap the balcony tap and any run of exposed metal, then tape the seam so it does not fill with water.
• Shut off and drain the balcony washing-machine tap. If you can close the isolating valve for that tap and let the remaining water run out of the hose, there is nothing left in the line to freeze. In a hard winter this is the highest-value five minutes you will spend.
• Pack the meter box. If the meter box is empty, stuff it with insulation material or old towels and keep the cover shut.

Three things never to do to a frozen pipe

Safe first aid you can do yourself

The principle is gentle, patient heat, applied from the tap end and working backwards. Warming the tap first gives melting water somewhere to escape; warming the middle of a frozen section traps meltwater between two ice plugs, and pressure builds.

1. 1Open the tap slightly, so that any water that melts can run out and you can see progress.
2. 2Wrap the tap and the exposed pipe in a towel soaked in warm — not boiling — water. Around 40–50°C is right. Replace it every five to ten minutes as it cools.
3. 3Or use a hair dryer on a low-to-medium setting, moving constantly, starting at the tap and working slowly back along the pipe. Keep it moving; never hold it in one place, and keep it away from standing water.
4. 4Warm the room. Close the balcony window, put a heater in the space if you have one, and give it time.
5. 5Watch the tap. When water starts to trickle, keep it running for a few minutes to clear the remaining ice out of the line.

If nothing changes after around two hours of this, the ice is almost certainly not in the section you can reach — it is inside a wall, under the floor, or in the buried supply line. At that point more towels will not help, and it needs equipment.

If the pipe has already burst

A pipe that froze and then split often looks fine until it thaws — and then water arrives all at once. Deal with the water first, the diagnosis second.

1. 1Shut off the main valve for your unit. It is usually in the water meter box (계량기함) by your front door or in the corridor, or under the kitchen sink. Find it now, while everything is dry, so you are not looking for it in the dark with water running.
2. 2Turn off electrical power to any area where water is reaching sockets or appliances.
3. 3Photograph and film everything before you mop up — the source, the affected floor and walls, and anything damaged. If this ends up in a discussion with your landlord, an insurer or the building office, the photos are what settle it.
4. 4If water is going through the floor to the unit below, tell the building management office (관리사무소) immediately as well as the neighbour. Damage below spreads fast and is far more expensive than the pipe.
5. 5Send us the photos on KakaoTalk or WhatsApp with your address, and we will tell you what we are looking at before we arrive.

What we do on a frozen-pipe call

Thawing is a separate service from drain unblocking, and it uses different equipment. Our Korean service page for it is 수도·배관 해빙 — this is what the work involves.

1. 1Narrow it down on the phone first: is the whole home without water, only one tap, or only the hot water? That tells us how much of the line is frozen before anyone travels.
2. 2On site we check the meter box, the exposed pipework and the boiler manifold to find where the ice is and what the pipe is made of — steel, copper, PB or PEX. The material decides the method.
3. 3We locate the main valve and prepare the access route before applying any heat, because a frozen section can already be split.
4. 4Metal pipe is thawed with a transformer-type electric thawing machine, which clamps electrodes to each end and warms the pipe itself — it works through buried and concealed sections. Non-metal pipe (PB, PEX, PVC) is thawed with a high-temperature steam thawing machine: a thin hose is fed inside the pipe and melts the ice directly. Mixed-material runs and buried supply lines use the steam method.
5. 5Once water flows, we flush the remaining ice out and check the meter and joints for leaks caused by the freeze. If the meter keeps turning, we locate the split with acoustic and thermal leak-detection equipment and replace only that section.
6. 6Where the same run keeps freezing, we advise on insulation and heating-cable work for that section.

We do not publish a flat price for thawing, because the job depends on where the ice is and how long the frozen run is: an exposed meter or indoor pipe usually clears in about 30 minutes to an hour, while a concealed run inside a wall or a buried supply line can take one to two hours or more. Send a photo of the tap, the meter box and any exposed pipe on KakaoTalk or WhatsApp and we will give you an estimate from the photos before we come.

If you are renting

Freeze damage is one of the situations where responsibility genuinely varies. It can turn on what the lease says, whether the pipe is inside your unit or part of the building's fixed equipment, whether the home was left unheated while empty, and what the building's own rules are. There is no single answer that applies to every tenancy.

What helps in every version of that conversation is evidence collected at the time: photos of the frozen or burst section, photos of the damage before you clean up, and a written record of what was found and what was done. We issue a written work report in English and Korean, with photos and — where relevant — camera footage, so you have something to forward to a landlord, an agent or a management office rather than relaying a Korean explanation second-hand.