When water freezes in a pipe, it expands. In the worst case, the pressure bursts the pipe — and because ice does not flow, the damage often only shows when it thaws. Pipes in cold, little-used rooms and in houses that stand empty in winter are most at risk. This article shows where pipes freeze, how to prevent it, what to do when a pipe is frozen or has burst, who has to report what, and which insurance is responsible in the canton of Zurich. If water is already escaping: our emergency plumbing service is available around the clock on +41 76 524 98 98, and is usually on site within 60 to 120 minutes in Zurich and the Limmat Valley.
Where pipes freeze
Any water pipe that is exposed to frost for a longer period and in which the water stands still is at risk. Typical places:
- Unheated rooms: basements, garages, attics and storage rooms, especially if a window is open or does not close properly.
- Outside taps and garden pipes: the pipe runs through the outer wall and is often still full in winter.
- Pipes in outer walls: if insulation is inadequate, pipes inside the masonry can freeze too.
- Holiday homes and empty flats: where nobody lives, no water flows, and the heating often runs on a low setting. This also applies to vacant flats between two tenancies.
The first signs are a tap that delivers no water or radiators that no longer get warm.
Prevention: what to do before the first frost
- Shut off and drain pipes in unheated rooms: close the shut-off valve, open the taps and let the remaining water run out. This also applies to the pipe supplying the outside tap.
- Never turn radiators off completely — not at night either, and not when the flat is empty. The frost-protection setting is not enough: it only protects the radiator itself, not the pipes in the room.
- Close windows, especially basement windows, when you are away for a longer time.
- If you are away for a longer period, close the main stopcock and then open all the taps so that the remaining water drains from the pipes. If a property stands empty for some time, ask someone you trust to check on it once a week.
- Insulate exposed pipes in cold rooms. Where that is not enough, a heating cable with a thermostat laid along the pipe gives protection. The electrical connection is made by a licensed electrical contractor, coordinated by us.
- Know where your main stopcock is: check where it is and whether it turns before winter, not in an emergency.
For property managers, a short walk-round before winter pays off: outside taps drained, basement windows closed, heating left on in vacant flats, shut-off valves accessible.
The pipe is frozen
If no water comes out but the pipe is still intact: do not thaw it yourself. Anyone who de-ices a pipe themselves can easily expose it to too much heat — which can cause further damage and knock-on damage. Close the main stopcock so that no water runs out when it thaws, in case the pipe has cracked. Heat the room and call a plumber, who will thaw the pipe in a controlled way and then check that it is watertight.
The pipe has burst
- Shut off the water: close the main stopcock, usually in the basement by the water meter.
- Make the electrics safe: unplug electrical appliances in the wet area and switch off the fuses for the affected rooms — but only if you do not have to stand in water to do so. If anyone is in danger or water has reached electrical installations: fire brigade, 118.
- Limit the damage: soak up the water, move furniture and valuables out of the wet area, and tell the neighbours below. Under Art. 38a of the Insurance Contract Act (Versicherungsvertragsgesetz, VVG), the person entitled to claim must, after the insured event, do what is reasonably possible to reduce the damage.
- Document: take photos of the burst, the water, wet walls and floors before anything is cleared up or opened. Before the damage has been assessed, you may not make changes without the insurer's consent that would make it harder to establish the cause or the damage — unless they serve to reduce the damage (Art. 38b VVG).
- Call: our emergency plumbing service is available around the clock on +41 76 524 98 98, usually on site within 60 to 120 minutes in Zurich and the Limmat Valley. More on the Plumbing emergency Zurich page.
Who has to report what
Tenants report the damage immediately to the property management or the landlord. Under Art. 257g of the Swiss Code of Obligations (OR), the tenant must notify the landlord of defects that he is not obliged to remedy himself; if he fails to do so, he is liable for any damage the landlord incurs as a result. Tenants must also use the rented property with due care (Art. 257f para. 1 OR). The property management decides on the repair.
Owners and property managers report the damage to the insurer as soon as they become aware of it (Art. 38 VVG); many insurers have a claims hotline for this. Damaged furniture and clothing are a matter for the occupants' household contents insurance (Hausratversicherung).
Insurance: frost is not a case for the GVZ
The cantonal building insurance, Gebäudeversicherung Kanton Zürich (GVZ), insures buildings against fire and natural hazards. According to the GVZ, frost damage and damage caused by burst pipes are not included: they are to be covered on a voluntary basis by a private building water insurance (Gebäudewasserversicherung). The GVZ does not insure furniture and other movable property either. According to the Swiss homeowners' association (Hauseigentümerverband Schweiz, HEV), building water insurance usually includes frost damage at no extra charge — repair and thawing of pipes and connected appliances inside the building, and of buried pipes outside it. Whether this applies to your policy is set out in its terms and conditions.
Important for holiday homes and empty properties: if damage was caused through gross negligence, the insurer may reduce its benefit in proportion to the degree of fault under Art. 14 para. 2 VVG. What applies in an individual case depends on the policy and the circumstances.
Repair with pressure test and test report
Once the cause has been found, we replace the damaged section of pipe. If the same pipe runs through a cold area, we check whether other points are at risk and suggest insulation or a different route. We test every new or repaired pipe with a pressure and leak test and give you the test report — a document that insurers and property managers can use. For new water pipes, we charge CHF 55 to 70 per linear metre including the pressure test, labour excluding VAT, materials separate.
If walls or floors are soaked, restoration follows: strip-out, technical drying, which we coordinate, then plastering, tiling, parquet and painting from one company — more on the Restoration after water damage page. You receive the fixed-price quote within 48 hours of the site visit, item by item, labour and materials separate, ready to forward to your insurer. The first steps for any water damage are described in the article Plumbing emergency: first steps.
This article is general guidance and replaces neither the instructions of the fire brigade and emergency services nor the terms of your insurance policy. Information on building insurance according to the GVZ, as of October 2026; information on building water insurance according to HEV Schweiz; prevention tips based on the guide published by Mobiliar; legal provisions according to fedlex.admin.ch. If anyone is in danger: fire brigade, 118.