Various sources recommend
home storage of a two week supply of water. The amount often recommended
is seven gallons per person for drinking and food preparation, and another
seven gallons per person for other limited uses such as hand washing,
teeth brushing and dish washing (total 14 gallons per person for two
weeks = 1 gallon per person per day). Both glass and plastic containers
are commonly used for water storage at home. Containers should
be clean and sanitary. Glass containers are breakable and somewhat
heavy compared to plastic, but they are not permeable to vapors and
gases, the amount of leaching (dissolving) of chemicals from glass into
water is insignificant. Plastic containers are lightweight and
substantially more resistant to breakage than glass.
If plastic containers are
used, care should be taken to assure that they are made of plastic approved
for food contact by the Federal Food and Drug Administration.
Polyethylene plastic is approved for food contact and is commonly used
for containers of various sizes, including 55-gallon
drums. Certain types of plastic containers are not intended
for food contact (such as vinyl plastic waterbeds, or trash containers)
and may leach undesirable chemicals into stored water. Leaching
of chemicals from approved plastics is negligible.
For long-term storage,
water should be sterilized or disinfected. Water stored in thoroughly
cleaned plastic or glass containers can be chemically disinfected for
long-term storage by treating each gallon with 16 drops of liquid chlorine
bleach (Clorox or Puree type bleaches, containing 4% to 6% sodium hypochlorite).
One teaspoon of bleach disinfects five gallons of water. This
level of treatment will prevent growth of microorganisms during storage.
Water stored in plastic
containers should not be stored near gasoline, kerosene, pesticides
or similar substances. Vapors from these substances could permeate
the plastic and affect the water. Thick-walled polyethylene containers
are significantly less permeable to vapors than are thin walled containers.
Be certain, when selecting a storage container for water, that it has
a tight fitting cap or lid to prevent entrance of contaminants and evaporation
of water. Because sunlight has an adverse effect on plastic, water
should be stored away from direct exposure to sunlight.
Sterilized or disinfected
water, stored in clean, food-approved containers with secure lids or
caps should be safe for use even after many years of storage.
Replacement of stored water with fresh water should be necessary only
if the stored water becomes contaminated in some way or if the container
should begin to leak. Be certain to label each container so there
will be no question about its contents. Include the date and information
on the method of disinfection used.