Locate the stop cock and turn off the mains water supply by turning your stop cock clockwise fully. If you can’t find it or it is stuck do the next step first while you sort it out.
If it is a cold/hot water feed leaking (or you are unsure) then turn on the taps and let them run down the sinks to reduce pressure in the pipes. Do not leave the plug in!
CAN’T FIND YOUR STOP COCK? It is often under the kitchen sink, in a garage or near to where your water supply enters the property, often in a front room in the corner, but not always. Isolate the stop cock by turning it clockwise fully until water stops coming from your taps when they are on.
if your stop cock fails you will normally have one on your front drive or on the pavement outside your property, normally under a small metal cover. Isolate the stop cock inside by turning it clockwise.
Be aware that there is water in the pipes and this may take some time to drain out before the leak stops depending on how big the leak is.
If the leak is on the cold water pipes then the above actions should minimise the leak until you can get an emergency plumber to fix it.</>
If the leak is on the hot water (not heating) pipes and you have a combi boiler then the above will stop the leak until you can get an emergency plumber to fix the leak.
If the leak is on the hot water (not heating) pipes and you have a standard boiler with a tank (usually in a warm my airing cupboard) then there will be a significant amount of water in the header tank to drain before the leak stops, so turn on your hot taps to drain the tank more quickly. You may want to fill up the bath while you are there as it may be a few hours before you can get access to warm water. Make sure there are no plugs in the sinks when running taps to reduce pressure.
If the leak is on the heating pipes and you have a combi boiler then you will need to wait for the radiator circuit to empty. You can reduce the amount of water that needs to drain by isolating the radiators – turn the taps on both sides of all the radiators fully clockwise to trap the water in the radiators.
If the leak is on the heating pipes and you have a standard boiler with a header tank in the loft then the tank will need to drain. Again isolate the radiators by turning the taps on each side clockwise to trap the water in the radiators. Also there may be an isolation valve on the feed from the header tank into the heating system so if you can get into your loft you may be able to stop water draining from the tank by turning this fully clockwise.
To catch water, buckets and old towels or similar (old because the water coming our of heating pipes can be black so do not use your good towels) may help to prevent water reaching delicate fittings such as wooden or laminate floors, skirting boards or cabinets etc, which may be severely damaged by exposure to water.
FINALLY CALL A RELIABLE EMERGENCY PLUMBER 033 33 052 999