In any survival situation, water is going to be a key component. For a family, if the tap suddenly goes dry or there is some sort of contamination in the water and you are no longer able to use city water, than a back up source will become critical within the day. Just think about how much water you use in just one day. I start the day with a glass of water and then start up a pot of hot water for tea. After that I fill a jug for the day's water to make sure I'm getting enough. Then the trip to the bathroom I use at least another gallon to use the toilet, wash my hands and brush my teeth. I haven't even hit the shower (where I'll go through another ten) and I've already gone through at least five gallons of water. But that's when I'm not forced to really think about how much I use. When I was in Mongolia, water had to be carried in from the river and boiled before being able to do anything as simple as brushing your teeth. The inconvenience of it alone was enough to make you conserve and then you realize how much waste there truly is. Really all one person needs for drinking and food preparation is a gallon a day. Another half gallon for sanitation purposes. So for a family of four, about five gallons per day.
The picture above is a great way for a family of four to collect and store water. The system consists of two five gallon buckets placed on top of each other. The buckets need to be food grade otherwise the plastic will leach into your drinking water. The top bucket contains a doulton ceremic water filter which is so efficient you can take water straight out of any water supply and have clean drinking water from it. It takes about two hours for the system to purify about a gallon of water so water that is placed in the top bucket will be ready to go by the next day. Add a spicket to the bottom bucket and its easy to get access to the water. This is a system that has been used successful by travelers around the world and it is an ideal addition to any family's preparedness list.
This system is one of the items that I sell or teach individuals to put together themselves. It can be a hassle gathering all the supplies up but you will save a lot of money by doing it yourself.