Water-related Emergencies & Outbreaks

Personal Preparation and Storage of Safe Water

After an emergency, such as a flood, hurricane, or earthquake, drinking water may not be available or safe to drink. As a result, residents may have to find a source of safe drinking water or know how to treat their water for use in certain activities, such as drinking, making ice, washing hands, and brushing teeth. The following information will tell you how to plan for treating and storing your water in the event of an emergency.

Create a Disaster Supplies Kit

Before an emergency:

Make sure you have a Disaster Supplies Kit. Be sure to include sanitation and hygiene items.
Pack the items in easy-to-carry containers. Duffle bags, backpacks, and covered trash receptacles are good candidates for containers.
Label the containers clearly.
Store the containers and the rest of your kit where they are easily accessible.
Print CDC flyers to keep in your kit:
- Make Water Safe
  - Make Water Safe - English [PDF - 325 kb]
  - Cómo desinfectar el agua (Make Water Safe) - Español [PDF - 424 kb]
- Drink Safe Water
  - Drink Safe Water - English [PDF - 109 kb]
  - Beba agua que sea segura (Drink Safe Water) - Español [PDF - 140 kb]

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Prepare an Emergency Water Supply

Store at least 1 gallon of water per day for each person and each pet. You should consider storing more water than this for hot climates, for pregnant women, and for persons who are sick.
Store at least a 3-day supply of water for each person and each pet (try to store a 2-week supply if possible).
Observe the expiration date for store-bought water; replace other stored water every six months.
Store a bottle of unscented liquid household chlorine bleach to disinfect your water and to use for general cleaning and sanitizing.

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Water Containers (Cleaning and Storage)

Unopened commercially bottled water is the safest and most reliable emergency water supply.

Use of food-grade water storage containers, such as those found at surplus or camping supply stores, is recommended if you prepare stored water yourself.

Before filling with safe water, use these steps to clean and sanitize storage containers:

Wash the storage container with dishwashing soap and water and rinse completely with clean water.
Sanitize the container by adding a solution made by mixing 1 teaspoon of unscented liquid household chlorine bleach in one quart of water.
Cover the container and shake it well so that the sanitizing bleach solution touches all inside surfaces of the container.
Wait at least 30 seconds and then pour the sanitizing solution out of the container.
Let the empty sanitized container air-dry before use OR rinse the empty container with clean, safe water that already is available.

Avoid using the following containers to store safe water:

Containers that cannot be sealed tightly
Containers that can break, such as glass bottles
Containers that have ever been used for any toxic solid or liquid chemicals (includes old bleach containers)
Plastic or cardboard bottles, jugs, and containers used for milk or fruit juices

For proper water storage,

Label container as "drinking water" and include storage date.
Replace stored water that is not commercially bottled every six months.
Keep stored water in a place with a fairly constant cool temperature.
Do not store water containers in direct sunlight.
Do not store water containers in areas where toxic substances such as gasoline or pesticides are present.

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Make Water Safe

Water often can be made safe to drink by boiling, adding disinfectants, or filtering.

IMPORTANT: Water contaminated with fuel or toxic chemicals will not be made safe by boiling or disinfection. Use a different source of water if you know or suspect that water might be contaminated with fuel or toxic chemicals.

Boiling

If you don’t have safe bottled water, you should boil water to make it safe. Boiling is the surest method to make water safer to drink by killing disease-causing organisms, including viruses, bacteria, and parasites.

You can improve the flat taste of boiled water by pouring it from one container to another and then allowing it to stand for a few hours, OR by adding a pinch of salt for each quart or liter of boiled water.

If the water is cloudy,

Filter it through a clean cloth, paper towel, or coffee filter OR allow it to settle.
Draw off the clear water.
Bring the clear water to a rolling boil for one minute (at elevations above 6,500 feet, boil for three minutes).
Let the boiled water cool.
Store the boiled water in clean sanitized containers with tight covers.

If the water is clear,

Bring the clear water to a rolling boil for one minute (at elevations above 6,500 feet, boil for three minutes).
Let the boiled water cool.
Store the boiled water in clean sanitized containers with tight covers.

Disinfectants

If you don’t have safe bottled water and if boiling is not possible, you often can make water safer to drink by using a disinfectant such as unscented household chlorine bleach or iodine. These can kill most harmful organisms, such as viruses and bacteria, but are not as effective in controlling more resistant organisms such as the parasites Cryptosporidium and Giardia.

To disinfect water,

Filter it through a clean cloth, paper towel, or coffee filter OR allow it to settle.
Draw off the clear water.
To use bleach, add 1/8 teaspoon (or 8 drops; about 0.625 milliliters) of unscented liquid household chlorine (5-6%) bleach for each gallon of clear water (or 2 drops of bleach for each liter or each quart of water),
- Stir the mixture well.
- Let it stand for 30 minutes or longer before you use it.
- Store the disinfected water in clean sanitized containers with tight covers.
To use iodine, follow the manufacturer’s instructions.

Chlorine dioxide tablets are another disinfectant that now is available in some outdoor stores. This disinfectant has proven to be effective against pathogens, including Cryptosporidium, if the manufacturer’s instructions are followed.

Filters

Many portable water filters can remove disease-causing parasites such as Cryptosporidium and Giardia from drinking water. If you are choosing a portable water filter, try to pick one that has a filter pore size small enough to remove both bacteria and parasites. Most portable water filters do not remove viruses.

Carefully read and follow the manufacturer’s instructions for the water filter you intent to use. After filtering, add a disinfectant such as iodine, chlorine, or chlorine dioxide to the filtered water to kill any viruses and remaining bacteria. For more information about water filters, see the Water Treatment Resources section.

Water Treatment Resources

To learn more about water filters and treatments that can remove microorganisms such as viruses, bacteria, and parasites (such as Cryptosporidium), see the following resources:

A Guide to Water Filters
A Guide to Drinking Water Treatment and Sanitation for Backcountry and Travel Use covers information on the effectiveness of various water treatment methods. This guide is also available in PDF: Drinking Water Treatment Methods for Backcountry and Travel Use [PDF - 895.78 kb].
A Guide to Commercially-Bottled Water and Other Beverages
Emergency Disinfection of Drinking Water

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Finding Emergency Water Sources

Alternative sources of clean water can be found inside and outside the home. DO NOT DRINK water that has an unusual odor or color, or that you know or suspect might be contaminated with fuel or toxic chemicals; use a different source of water.

The following are possible sources of water:

Inside the Home

Water from your home’s water heater tank
Melted ice cubes made with water that was not contaminated
Water from your home’s toilet tank (not from the bowl), if it is clear and has not been chemically treated with toilet cleaners such as those that change the color of the water
Liquid from canned fruit and vegetables

Listen to reports from local officials for advice on water precautions in your home. It may be necessary to shut off the main water valve to your home to prevent contaminants from entering your piping system.

Outside the Home

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

Water from sources outside the home must be treated as described in Make Water Safe. DO NOT DRINK water that has an unusual odor or color, or that you know or suspect might be contaminated with fuel or toxic chemicals; use a different source of water.

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