Emergency water kit

Ready.gov says to store at least one gallon of water per person per day for several days, for drinking and sanitation, and notes that water needs can double in very hot temperatures (Ready.gov). CDC says to store at least 1 gallon per person per day for 3 days, and to try for a 2-week supply if possible (CDC). This list covers storing that water and treating more if you run short. The emergency water guide goes through each method step by step.

Storing water

• Buy bottled water if you can. Ready.gov says to store commercially bottled water in its sealed original container in a cool, dark place (Ready.gov).
• Use food-grade containers if you fill your own. CDC says FDA-approved food-grade water storage containers are best, and never to use containers that held toxic chemicals such as bleach or pesticides (CDC).
• Label and rotate. CDC says to label each container “drinking water” with the storage date, and to replace self-filled water every 6 months (CDC).
• Store it cool and dark. CDC says to keep containers between 50°F and 70°F, out of direct sunlight, and away from gasoline and pesticides (CDC).

A household of four at one gallon per person per day needs 12 gallons for three days, which is two of the 7-gallon containers on this list. CDC’s 2-week goal for the same household is 56 gallons. For a larger supply:

• Stackable containers fit a closet or under a bed in an apartment. Keep them in the same cool, dark place.
• A 55-gallon food-grade drum holds about a 2-week supply for a household of four. Label and rotate it like any other container.
• A bathtub liner is filled from the tub faucet when a storm is forecast. No federal source covers bathtub storage, so treat it as extra water on top of a stored supply, not in place of one.

Treating water

Bleach. Use regular unscented household bleach. Ready.gov says not to use scented, color-safe, or added-cleaner bleaches (Ready.gov). CDC says to follow the label’s instructions for disinfecting drinking water. For bleach that is 5% to 9% sodium hypochlorite, CDC gives these amounts per gallon of clear water (CDC):

• With a dropper: 8 drops.
• With a measuring spoon: a little less than 1/8 teaspoon.
• If the water is cloudy, murky, colored, or very cold: double the amount.
• Let the water stand at least 30 minutes before drinking.

CDC lists different amounts for 1% bleach, so check the percentage on the bottle. Bleach is not on this list as a product: buy it locally and check the label. The dropper on this list is for measuring the drops.

Tablets. CDC says to follow the label on chlorine dioxide, chlorine, or iodine tablets, and that chlorine dioxide tablets will kill Cryptosporidium as long as you follow the instructions correctly (CDC).

Filters. CDC says portable water filters do not remove all types of germs. A filter needs an absolute pore size of 1 micron or smaller to remove parasites and 0.3 micron or smaller to remove bacteria, and filters will not remove viruses. After filtering, CDC says to add a chemical disinfectant such as iodine, chlorine, or chlorine dioxide to kill any viruses and bacteria (CDC). Both filters on this list are listed at 0.1 micron absolute: the squeeze filter for carrying, and the gravity filter for treating larger amounts at home. Pair either one with bleach or tablets.

Add these from home

Regular unscented household bleach, a large pot and a heat source you can use safely for boiling, clean cloth or coffee filters to strain cloudy water (Ready.gov), and clean, sanitized containers with tight covers for treated water (CDC).