FEMA recommends that each household keep two weeks of water for each person in the house. I can state for certain, this isn't one gallon per person. Think about all the times you turn on the water. Cooking, cleaning, washing clothes, taking a shower, brushing your teeth all require water. Not to mention what you need to drink in a day. If it is hot outside or if you are doing heavy physical work, you need even more.
Storing a lot of water is a challenge. It is heavy and takes up a lot of space. You really have to get creative to think about where you are going to put it. Here are a few places on the Internet that will give you some ideas:
The Safely Gathered In blog has a series of posts on water that covers storing water in two liter bottles, storing water in other containers, purifying water, and finding some unique sources of potable water.
The Prepared LDS Family blog has a post on using 55 gallon drums to hold water.
Here is a picture of how I store most of my water. I can't have 55 gallon drums because I don't have the space. I do have the space for some five gallon containers shown here. I put them in my closets.
When you open the container to change the water after one year of storage, it may smell a bit musty. I will say, the first time I opened a water container that was stored for one year, I was a bit concerned about the smell. You can remove the musty smell by pouring the water back and forth between two containers to add some air to it. You can also filter it, if needed. I have drank water stored for one year and it tasted fine. But until you get used to it, the musty smell is a bit disconcerting. When rotating water, I usually use my stored water to water my houseplants.
This is one of the mylar bags I use to store my water.
Back into the closet it goes.
As you can see, I got these from Emergency Essentials. I have mentioned before how much I really like this store. I don't get any compensation to talk about them. I have been a satisfied customer for over three years.
While I have a few of these containers filled with water, it is not my only water storage. I have purchased some water storage containers from the big box stores as well (in the camping section). Those are nine gallon containers.
I consider this my first line of defense if I loose the ability to get water from the tap. However, if I had to rely on this water for an extended period of time, I would quickly run out. After that, I would have to rely on a secondary water source.
Most people don't realize it, but almost everyone has a secondary water source in their house that is potable. It is the hot water heater! Once the heater is completely shut off, you can drain the water and use it in an emergency. This should be between 30 to 50 or more gallons depending on the size of your hot water heater.
If any emergency continues beyond that, you must look for open water sources such as a local stream, swimming pool or pond. This water will need to be filtered to remove impurities, or boiled to make it safe. You can always boil it over an open fire if necessary or you can purchase filters such as this one. I have a Berkey Filter System for a 'just in case' emergency. If you are interested in a filter system for your own water storage program, you can search the Internet and find many different filtering options in different price ranges.
Be prepared to face an emergency...not scared!