You can't live for more than a few days without water. There are ways to filter and purify water which we can touch on another day, but you HAVE to have water available. When I was in high school, I was getting ready to go out in the evening and suddenly there was no water coming out of the tap. That has never happened to me before or since and so I ran over to the local grocery store to get some water. There were no more than a few other concerned people. They were buying carts full of water bottles. Turned out that someone crashed into an electrical transformer that cut power off to a city water pump. It was soon restored, but I will never forget the panic of suddenly and without warning, not having water available.
In your house, you probably have some water stored in a water heater. If you have some warning you can fill a bathtub and any containers you have with water. You can also give yourself some peace of mind by keeping it available in containers in case the unexpected happens. There are three tiers of water storage in my house. I just store it straight from the tap with no added chemicals. I just keep them stored in a cool place, out of the light. I personally have a water purifier so even If I have dirty, foul water I can still filter it and drink it. Here are the three ways I contain my water:
The first is a plastic juice bottle. We save them when we buy orange juice or lemonade or whatever. They are food grade and I wash them out with a little green clean to get rid of residual flavors and it does well. You could rinse it on the inside with a little water and baking soda as well. Don't use milk jugs. They are thin and deteriorate and it is difficult to wash out the proteins in the milk and not have it ruin your water. Fill it all the way as full as possible so there is no air in it.
Aquatianers (or any other brand of water jug) can be purchased for $15 plus at Walmart or any sporting goods store. They are modular and stack quite compact. This particular one hold 7 gallons. Traditionally, water storage barrels are blue. This color limits light exposure and biological growth (bacteria and algae) and also signifies that what is stored in the container is safe for human consumption (for example, gasoline is stored in red containers).
55 gallon barrels. This barrel is a food grade barrel I purchased from a contact at our local Pepsi plant. It is used to store soda syrups. I washed it out as well as I could and I fill it with a potable water hose that I use for hooking up my RV. Regular garden hoses can impart a bad taste. The water I store in here does not have a Mountain Dew taste anymore (Unfortunately :). Always store clean, uncontaminated water in your containers if you want to ensure that you have usable water when you need it. Later!