What to do in a plumbing emergency

1. 1

   Turn off the stopcock (usually under the kitchen sink) clockwise until it stops.

2. 2

   If water is near lights or sockets, switch off at the consumer unit, if you can reach it without standing in water.

3. 3

   Turn off the boiler and immersion heater, then open the cold taps and flush the toilets to drain the pipes.

4. 4

   Wrap a towel tightly round the split and put a bucket underneath.

5. 5

   Photograph the burst and any damage for your insurer.

Push-fit fittings and pipes in lofts, outside walls and under floors are the usual suspects in a cold snap.

1. 1

   Keep everyone out from under it, especially if it’s bulging or sagging.

2. 2

   Don’t use the light in that room. If water is coming through a light fitting, switch off at the consumer unit.

3. 3

   Turn off the stopcock. If the leak is from the flat above, their stopcock is the one that matters: knock, call, or contact the building manager.

4. 4

   Put a bucket under the drip and move furniture and electricals away.

In converted houses and blocks, water can travel along joists and come out a long way from the leak. We trace it back to the source.

1. 1

   Look for an isolation valve on the pipe feeding the tap, toilet or appliance: a small slotted screw. A quarter turn so the slot runs across the pipe shuts it off.

2. 2

   No valve, or it won’t turn? Use the stopcock.

3. 3

   For a leaking radiator, close both valves at either end (the cap on the lockshield may need a spanner).

4. 4

   For a leaking boiler or hot water cylinder, switch it off at the power too.

1. 1

   Stop flushing. If it’s about to overflow, lift the cistern lid and push the float up to stop it filling.

2. 2

   Stop using every tap, shower and appliance in the house: they all go to the same drain.

3. 3

   Try a plunger with firm, slow pushes. Avoid chemical unblockers on a toilet full of water.

4. 4

   Check the outside drain cover. If it’s full and neighbours are affected, it may be a shared sewer for Thames Water.

Two or more fittings blocked at once usually means the problem is further down the drain, not in the toilet.

1. 1

   Use the isolation valve under the tap or toilet: a quarter turn with a flat screwdriver.

2. 2

   An overflow pipe pouring outside usually means a float valve has stuck in a cistern or the loft tank. Isolate the cistern, or turn off the stopcock for the loft tank.

3. 3

   If nothing isolates it, turn off the stopcock and open a cold tap.

1. 1

   Check the stopcock is fully open (anticlockwise).

2. 2

   Ask a neighbour. If they’re off too, check Thames Water for work in your area before booking a plumber.

3. 3

   If it’s just you and it’s freezing outside, a pipe has probably frozen. See frozen pipes below.

4. 4

   If water is bubbling up in your front garden or the pavement, report it to Thames Water.

1. 1

   Turn off the stopcock first. Frozen pipes often split, and only leak once they thaw.

2. 2

   Open the tap the frozen pipe feeds so meltwater can escape.

3. 3

   Warm the pipe gently with a hairdryer or hot water bottle, working from the tap end back. Never use a naked flame.

4. 4

   If you find a split, leave the water off and call.

1. 1

   Check the boiler has power, the thermostat is calling for heat and the programmer is on.

2. 2

   Look at the pressure gauge. Below 1 bar on most combi boilers means it needs topping up through the filling loop (your manual shows how).

3. 3

   Note any fault code on the display: it tells us which part to bring.

4. 4

   Condensate pipe outside frozen? Pouring warm (not boiling) water over it often clears it.

Never take the boiler casing off. Gas work is for a Gas Safe registered engineer (567789).