Household water supplies, including drinking water, could be affected in a disaster so having a supply of stored water is absolutely essential. You need at least three litres of drinking water for each person each day.
You will also need water for washing and cooking.
Label each bottle with dates showing when the bottles were filled and when they need to be refilled. (Preferably every six months.)
Store bottles away from direct sunlight in a cool dark place. Keep them in two separate places and where there is not likely to be flooding.
NZ Survivor recommends having at least 2 x 5ltr containers, per household member.
These containers are ideal as they are not too heavy to carry.