Make sure you know where you turn off the main water supply to your house. Usually this will be near the path just inside or outside your property boundary either as a cover set in the concrete (outside) or in a moulded plastic council supplied toby box with a blue or black lid (inside). In some older properties it may be wood. Generally all will need a regular (flathead) screw driver open it.
If you have a house built prior to the 80’s it will normally be in line with the hose tap at the front of your house.
If for some reason there is a flood within your property, turn the tap off in a clockwise direction and call Your Local Plumber immediately on 0800 Local Plumber (0800 562 257).