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Emergency Preparedness:
Storing an Emergency Supply of Water

Most households keep emergency kits of supplies they can quickly turn to when there is a major earthquake or another type of disaster.

How much water should I store?
How long should I keep water stored?
How should I store water?
Where should I store water?
What about using bleach to purify my water?
Emergency outdoor water sources
Hidden water sources in your home
Three ways to treat water
Links to water and disaster preparation

A supply of stored water may be your most important survival item. You need to take precautions to make sure your water is safe to drink when you need it most.

Should there be a major calamity, be sure to listen to your local radio stations or check this website for more information on the condition of the Contra Costa Water District's water supply.

Call our Water Quality Hotline at (925) 688-8156 for more information, or if it's an emergency, call (925) 688-8374.

How much water should I store?

The Department of Homeland Security recommends that you store at least one gallon of water per person, per day and keep a three-day supply of water on hand. The American Red Cross also recommends one gallon of water per person per day, but with a two-week supply for every person in your household. For a family of four, that's 56 gallons of water.

How should I store water?

Use clean containers of heavy, opaque plastic with screw-on caps. The American Red Cross suggests clean plastic soft drink bottles (it's very difficult to clean them), food-grade plastic containers or drums. Don't re-use plastic milk containers, since they are extremely difficult to clean completely and can contaminate your stored water. There are a number of commercial water storage containers available designed for storing drinking water.

You can also buy commercially bottled "spring" or "drinking" water and store it for up to a year.

Where should I store water?

Store containers of water out of the direct sunlight in a place that is also cool and dry. Keep it in a handy place, where you can get to it quickly and safely, even after an earthquake.

How long should I store water?

You can safely store water for six months to a year, depending on how it is packaged.

If it's commercially-bottled "spring" or "drinking" water, the American Red Cross recommends you can keep it stored for a year as long as the container isn't opened. Once the container is opened, use the water immediately.

It's much less expensive to store tap water in your own containers, it's recommended you store tap water for six months maximum.

It's a good idea to label and date the water bottles or containers.

What about using bleach to purify my water?

If you're using treated tap water -- like CCWD tap water -- and you do not need to purify the water before storing it in a clean container. You will not need to purify the water when you use it, if it's been stored for less than six months, again in a clean container.

Hidden emergency water sources in your home
If a disaster catches you without a stored supply of clean water, you can use the water in your hot-water tank, pipes and ice cubes. As a last resort, you can use water in the reservoir tank of your toilet (not the bowl).

Do you know the location of your residence's incoming water valve? You'll need to shut it off to stop contaminated water from entering your home if you hear reports of broken water or sewage lines. Check radio or TV news -- or this website if it's possible -- to see if a "boil water" notice has been issued for your area.

To use the water in your home's pipes, let air into the plumbing by turning on the faucet in your house at the highest level. A small amount of water will trickle out. Then obtain water from the lowest faucet in the house until the stored supply is depleted.

To use the water in your hot-water tank, be sure the electricity or gas is off, and open the drain at the bottom of the tank. Start the water flowing by turning off the water intake valve and turning on a hot-water faucet. Do not turn on the gas water heater or electricity when the tank is empty.

Emergency outdoor water sources
If you need to find water outside your home, you can use these sources. Be sure to treat emergency outdoor water according to the instructions below:

  • Rainwater
  • Streams, rivers and other moving bodies of water
  • Ponds and lakes
  • Natural springs

Avoid water with floating material, an odor or dark color. Use saltwater only if you distill it first. You should not drink flood water.

Three ways to treat water
In addition to having a bad odor and taste, contaminated water can contain microorganisms that cause diseases such as dysentery, typhoid and hepatitis. You should treat all water of uncertain purity before using it for drinking, food preparation or hygiene.

There are many ways to treat water for human consumption. None is perfect. Often the best solution is a combination of methods.

Two easy treatment methods are outlined below. These measures will kill most microbes but will not remove other contaminants such as heavy metals, salts and most other chemicals. Before treating, let any suspended particles settle to the bottom, or strain them through layers of paper towel or clean cloth.

Boiling: Boiling is the safest method of treating water. Bring water to a rolling boil for 3-5 minutes, keeping in mind that some water will evaporate. Of course, let the water cool before drinking.

Boiled water will taste better if you put oxygen back into it by pouring the water back and forth between two clean containers. This will also improve the taste of stored water.

Disinfect ion: You can use household liquid bleach to kill microorganisms. Use only regular household liquid bleach that contains 5.25 percent sodium hypochlorite. Do not use scented bleaches, color safe bleaches or bleaches with added cleaners.

The American Red Cross recommends that you add 16 drops of bleach (1/4 teaspoon) per gallon of water, stir and let stand for 30 minutes. If the water does not have a slight bleach odor, repeat the dosage and let stand another 15 minutes.

The only agent used to treat water should be household liquid bleach. Other chemicals, such as iodine or water treatment products sold in camping or surplus stores that do not contain 5.25 percent sodium hypochlorite as the only active ingredient, are not recommended for use by the American Red Cross.

While the two methods described above will kill most microbes in water, distillation will remove microbes that resist these methods, and heavy metals, salts and most other chemicals.

Distillation: Distillation involves boiling water and then collecting the vapor that condenses back to water. The condensed vapor will not include salt and other impurities. To distill, fill a pot halfway with water. Tie a cup to the handle on the pot's lid so that the cup will hang right-side-up when the lid is upside-down (make sure the cup is not dangling into the water) and boil the water for 20 minutes. The water that drips from the lid into the cup is distilled.

For more information on storing water and disaster preparation, please look at these web sites:

American Red Cross

American Red Cross Emergency Preparedness Guide

FEMA Guide To Storing Water For An Emergency

FEMA Guide to Managing Your Water During an Emergency

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