It is difficult to underestimate the importance of having clean, drinkable water. It is said that humans can live three minutes without air, three days without water, and three weeks without food. Water should be a primary focus when preparing for disasters.
You may take a couple of different approaches to making sure that you have enough water after a disaster. You can stockpile enough water to last for an extended period of time or you can keep empty containers with the hope of being able to fill them before or after the disaster strikes. The advantage of stockpiling water is that you have a sure and ready supply. The disadvantage is that is heavy and takes a good deal of space. It also needs to be stored properly and rotated to remain fresh.
Remember that you will need water not only to drink but for sanitation and hygiene as well. Many of the worst bacteria-related illnesses are the result of fecal-oral contamination. Keeping yourself and your environment clean is extremely important during a disaster.
Standard emergency guidelines suggest that you store one gallon per day for each member of your family for at least a two week period. If the temperatures are hot or activity is high then that amount can double. Children, nursing mothers, or those who are ill may need more water as well. Don't forget about water for sanitation and hygiene as well. You must consider your family's personal needs and habits when deciding how much water to store. Your storage space and personal situation may also help dictate whether you store more or less water. You may need to adjust some of your habits.
WA State Department of Health:
Environmental Protection Agency:
WA State Department of Ecology:
Centers for Disease Control and Prevention:
United States Geological Survey: