Do this first
- Electrics first if water is anywhere near them. If it is running near a consumer unit, a socket, a light fitting or into a ceiling void with downlights, switch off at the main switch before you start wading about. Do not touch a consumer unit that is already wet; if you cannot reach it safely, stay out of the room and call the electricity network operator.
- Close the internal stopcock. Usually under the kitchen sink, in a cloakroom, under the stairs, or where the main enters the building.
- Open the kitchen cold tap fully and leave it running. That drains the rising main so it stops feeding the split.
- Open every other cold tap and flush the WCs once to pull the remaining water down and out.
- Switch off the boiler and the immersion heater. Running either dry damages it.
- Watch the flow for a minute or two. If it slows and stops, the split is inside the house and downstream of the stopcock. If it keeps running at the same rate, the split is upstream of the stopcock, on the buried supply pipe outside, and you now need the external stop valve in the pavement or path, which takes a long key.
- Contain rather than repair. Buckets, towels, and where the water is running along a ceiling void, the controlled drain described on water coming through a ceiling, with its conditions.
- Photograph everything before you clear up. Wide shots, close-ups, the time on your phone.
Where the split is, and what caused it
The one-minute test above splits this into two very different jobs. Inside the house, the water stops when the stopcock closes and the repair is a cut-out and remake. Outside, on the supply pipe between the boundary and the building, it does not stop, and the repair involves excavation and a different set of decisions about who pays.
| Evidence | Where it is |
|---|---|
| Flow stops within a minute or two of closing the stopcock | Internal pipework |
| Flow continues unchanged with the stopcock shut | Buried supply pipe, your side of the boundary |
| Water surfacing in the street, or the pavement chamber flooded | The main or the communication pipe: the water company's |
| Boiler pressure collapsed, taps still fine, water inside | Heating circuit rather than the cold main |
Cause tends to follow the season and the material. Freeze and thaw splits copper along its length in lofts, garages and unheated voids, and the split usually only reveals itself when the ice melts, which is why the flood arrives on the mild day rather than the cold one. Old lead and galvanised steel fail from corrosion and ground movement. Push-fit joints fail when the pipe insert was left out at installation. A split fed from a cistern in the loft rather than the main will keep running even with the stopcock shut until the tank empties, so check for a header tank before assuming the leak is outside.
What the repair involves
Internally, the damaged section is cut out and remade in copper or push-fit to match, the run is pressure tested before anything is closed up, and where the split happened because the pipe was unlagged in a cold void, it gets lagged, because otherwise you will be doing this again next winter. Externally, the leak point is located acoustically before anything is dug, so the excavation is a single hole rather than a trench, and the pipe is repaired or replaced in MDPE.
Then the part most firms leave: the water has usually gone through a ceiling, a floor or a wall. Saturated plasterboard is cut back to sound board, the void is dried, and the ceiling is reboarded, skimmed and repainted; floors are lifted, dried and relaid. That is the whole of burst pipe repair as we do it. If the freeze has not yet burst anything, our guide to thawing frozen pipes safely is the one to read before you reach for a heat gun.
When it is not us
- Water surfacing in the road or the pavement. That is the water company's main or communication pipe. Report it to them; there is nothing for you to pay.
- The consumer unit is wet, or the lights tripped and will not reset. That is an electrician, after the water is stopped. Do not keep resetting a breaker that trips.
- You smell gas. Leave the building, do not touch switches, and ring the national gas emergency service, whose number is on your gas bill.
- Structural damage, or a ceiling that has already come down on someone. Ring 999 if anyone is hurt or trapped, then deal with the plumbing.
- A pipe in a communal riser, or a burst in common parts of a block. That is block management's to instruct, however wet your flat is.
- You rent. Call the landlord or agent first. They hold the repairing obligation and normally their own emergency contractor.
- Your insurer runs an emergency helpline. Using it may be a condition of the policy. Check before you instruct anyone, including us.