Water

How much you need

Plan on 1 gallon per person per day: about half for drinking and half for cooking and basic washing. Store more for:

• hot weather, nursing mothers, sick people and kids (they need more)
• pets (about 1 ounce per pound of body weight per day for dogs and cats)
• your well pump or city water being off for a long time

Use the water & food calculator for your exact household.

Storing water

Store-bought bottled water is the easiest. Keep it sealed, in a cool dark place, and use it by the date on the package.

Filling your own containers works great and costs almost nothing:

1. Use food-grade containers: water jugs, 5–7 gallon water boxes, 55-gallon blue barrels, or cleaned 2-liter soda bottles. Never use milk jugs (they break down and are hard to clean) or anything that held chemicals.
2. Clean them: wash with soap and water and rinse. Then sanitize: mix 1 teaspoon of unscented household bleach in 1 quart of water, slosh it around every surface, wait 30 seconds, pour it out, and let it air-dry.
3. Fill with tap water. If your water is from a public utility, it's already treated. If it's from a well, add 2 drops of unscented bleach per gallon before sealing.
4. Label with the date and replace every 6 months.
5. Store away from sunlight, gasoline, pesticides and paint. Plastic lets fumes through.

Hidden water in your home

When the taps stop, you probably still have dozens of gallons:

• Water heater: 30–80 gallons. Turn off the power or gas first. Close the cold-water inlet valve on top, open a hot faucet in the house to let air in, then drain from the valve at the bottom. The first bit may have sediment — let it settle.
• Pipes: open the highest faucet in the house, then collect water from the lowest one.
• Ice cubes and frozen water bottles in the freezer.
• Toilet tank (not the bowl) — fine for flushing or washing, and drinkable after treatment if it has no blue cleaner.
• Canned fruit and vegetable liquid.

Don't drink water from radiators, waterbeds, pools or hot tubs (use for flushing/washing only).

Making water safe

If officials issue a boil-water notice, or you're using any water you're not sure about, treat it. Pick one method.

1. Boiling (best)

Bring clear water to a rolling boil for 1 minute (3 minutes above 6,500 ft elevation). Let it cool, then store in clean, covered containers. Pour it back and forth between two clean containers to improve the flat taste.

2. Unscented household bleach

Use plain, unscented chlorine bleach — check the label for 6% or 8.25% sodium hypochlorite. Don't use scented, "splash-less" or color-safe bleach.

Stir, then wait at least 30 minutes. The water should have a faint chlorine smell. If it doesn't, repeat the dose and wait another 15 minutes. Use the bleach calculator for other amounts.

3. Filters and tablets

• Portable filters (like hiking filters) remove bacteria and parasites. Most do not remove viruses, so add bleach or boil afterward if the water may contain sewage.
• Chlorine dioxide tablets work on most germs, including some that resist plain chlorine. Follow the package wait time — often 30 minutes to 4 hours.

Cloudy water?

Let it settle, then pour off the clear water. Or strain it through a clean cloth, paper towel or coffee filter. Then treat it.

Wells and city water

• On a well? No power means no pump. A generator, a solar pump or a hand pump solves this. After floods, have the well tested before drinking.
• City water usually keeps flowing at first, because water systems have backup power. But a long regional outage can drop pressure. If that happens, expect a boil-water notice.

Sources: CDC — Water in an Emergency · EPA — Emergency Disinfection of Drinking Water · FEMA — Food and Water in an Emergency · Ready.gov — Water