Most sources recommend 1 gallon of water per person, PER day, for 14 days.
Store water in “FOOD GRADE” or PETE plastic containers (stay away from milk jugs- soda bottles are suitable).
Store water away from too much light or heat.
Clean, sanitize, and rinse all containers prior to use.
Do not use containers previously used to store non-food products.
Do not store water containers directly on concrete. Place on cardboard, block of wood, or other materials.
Non-chlorinated water (most municipal water is chlorinated) should be treated with bleach. Add 1/8 of a teaspoon (8 drops) of liquid household chlorine bleach (5 to 6% sodium hypochlorite) for every gallon (4 liters) of water.
Boiling is the safest way to clean water, however you can use household liquid bleach to kill microorganisms. Make sure you use regular bleach, not the scented ones.
Baby Step #2 from http://foodstoragemadeeasy.net