Guidelines on Emergency Water Storage and Purification

boy drinking water

Introduction

Having potable water available for immediate use is one of the most important ways to help your family be prepared for an emergency. Water is more essential to sustaining life than food, so it is one of the first items you should collect and store. Follow these guidelines on creating an emergency supply of water to ensure that your supply is sufficient and safe to use.

What Should I Use for Water Storage?

The most common sources of water for storage are bottled water, tap water, and water stored in a cistern.

• Bottled water: Storing commercially bottled water in plastic containers made of polyethylene terephthalate (PETE or PET) is a safe and easy option. Avoid plastic containers that are not PETE plastic.

• Tap water: Packaging and storing water from the tap requires time and effort but is a very economical choice.

• Cistern: If budget and space allow, you may consider storing water in a cistern. These large tanks are often stored underground for the purpose of capturing rainwater but can also be filled with water from other sources.

How Do I Prepare Water to Be Stored?

If you choose to package water for emergency storage yourself, consider the following guidelines:

Choosing a Container

Water storage containers should be airtight and resistant to breakage. Plastic soda bottles are commonly used. Do not use containers previously used to store nonfood products, and do not use plastic milk jugs because they do not seal well and tend to become brittle over time. With any water storage container that you plan to use, thoroughly wash and sanitize before filling.

Water Pretreatment

Use these guidelines to treat water before adding it to a container:

• Chlorinated, clear: If the water has been treated with chlorine by a water utility, you do not need to treat it before storing.

• Not chlorinated, clear: If the water is not chlorinated and is clear, add 8 drops of household bleach (5 to 9 percent sodium hypochlorite) per gallon. Only use household bleach without thickeners, scents, or additives.

• Not chlorinated, cloudy: If the water is not chlorinated and is cloudy, add 16 drops of household bleach per gallon.

How Do I Store Water Safely?

Once the water has been treated and added to containers, do the following:

• Seal the containers tightly.

• Add the date.

• Store in a cool, dark place.

Since many containers are clear and light can permeate them, you may want to cover them or store them in dark plastic bags. Some containers may also require protection from freezing. Store water only where potential leakage would not damage your home or apartment. If using bottled water purchased from a store, use the “best if used by” dates as a rotation guideline. Otherwise, replace water every six months.

girl drinking from a water bottle

How Much Water Should I Store?

Although it is difficult and impractical to store water in large quantities, experts recommend that you keep a two-week emergency supply of water on hand since natural disasters may pollute or disrupt water supplies for that long. Adults need to drink at least 2 quarts of water each day. Children, nursing mothers, and those who are sick or have health conditions may need more. Additional water is needed for food preparation and hygiene for a total of 1 gallon per adult per day. For a two-week supply, store 14 gallons (53 liters) of water per adult.

What Are Good Sources for Water in an Emergency?

If you run out of water storage or do not have a supply, there are other water sources you can use in an emergency. You will need to purify water from some of these water sources to ensure that it is safe to use. Water should be avoided if it was chemically treated or is contaminated. Possible sources of water include:

Inside the Home

• Water heater

• Water remaining in pipes

• Canned fruits and vegetables

• Toilet tank

• Ice cubes

Outside the Home

• Rainwater

• Well water

• Natural springs

• Streams and rivers

• Ponds and lakes

In addition to these sources, you can use water from swimming pools and spas for hygiene and cleaning—however, it should not be consumed.

How Do I Know If Water Is Safe to Use?

If your water is dirty, you should purify it before using. If you think your water may have been contaminated, do not use. Consuming water that is contaminated with chemicals, fuel, toxins, sewage, or waste can lead to serious illness. However, water will sometimes have a dusty taste after being stored. This does not necessarily mean it is contaminated. The taste of stored water can be improved by pouring it back and forth between two containers before use.

How Do I Purify Water?

If you don’t know if your water supply is safe or if it has become polluted, it should be purified before use. Water purification is generally a two-step process and will make water safe to use.

Step 1: Clarifying Water

Cloudy or dirty water must first be made clear. It should be passed through filter paper, fine cloth, or some other filter. You can also allow the dirt to settle, and then carefully draw the clear water on top. Filtered or clear settled water should always be disinfected before use.

Step 2: Disinfecting Water

• Boiling method: Bringing water to a rolling boil for 3–5 minutes will kill most waterborne microorganisms. A higher elevation requires longer boiling. However, prolonged boiling of small quantities of water may concentrate toxic contaminants if present.

• Bleach method: Adding 8 drops of fresh liquid household chlorine bleach (5 to 9 percent sodium hypochlorite) to every 4 liters (1 gallon) of water will kill most microorganisms. Only use household bleach without thickeners, scents, or additives. The use of bleach does not address toxic contamination.

• Water filters: Some commercial water filters can effectively filter and purify water contaminated with microorganisms, toxic chemicals, and heavy metals. Their effectiveness depends on design, condition, and proper use.