Storing and Treating Water

Storing drinking water is a critical part of being prepared for an emergency. Learn more about how much you should have, how to store it, and how to treat water if you need more.

Experts say there is more than a 60 percent chance that a major earthquake will occur in the Bay Area within the next 30 years. After such an event, your water supply might be unavailable for 72 hours or more.

This is why it is critically important to be prepared with an emergency water supply to ensure that you and your family have drinking water even in the event of a disaster.

How Much Water Do I Need in My Emergency Water Supply?

• Each family member needs one gallon of water per day, and this estimate includes drinking water as well as water for limited cooking and personal hygiene.
• Don't forget your pets! They also need up to one gallon of water per day.
• It is recommended to store enough water to last for 3-5 days. For example, a family of 4 with one pet dog should have 15-25 gallons of emergency water.

Storing Tap Water

Tap water can be stored without any treatment. Use food-grade plastic containers, such as clean 2-liter soft drink bottles. Heavy-duty water containers are available at your local sporting goods store or online. Store tap water in a cool, dark place, such as under a sink or in the basement. Label the containers with the date of storage and replace the water every six months. When you drink your stored tap water, you do not have to treat it.

Storing Bottled Water

Store bottled water in a cool, dark place and in the original sealed containers. (It is not recommended to store bottled water after the seal has been broken.) If the bottles aren’t marked with an expiration date, label them with the date of purchase, and replace them every six months. When you drink your stored bottled water, you do not have to treat it.

Water Conservation Tip

What If Your Emergency Supply Runs Out?

If you run out of stored drinking water, don’t worry: you can treat water from certain sources in your home. You can treat water in the kitchen, just keep in mind that not all sources of water in your home are appropriate for drinking.

Which Sources of Water Can You Drink?

Sources of water you CAN treat and drink include:

• Water from your water heater.
• Water from your toilet reservoir tank.
• Water from your coffee maker reservoir.

Once you identify a source of potable water, you can treat it by disinfecting it or boiling it on a kitchen stovetop or camping stove.

Disinfecting Water*

To treat water by disinfecting it:

• Use regular household bleach (typically 5.25% sodium hypochlorite), not the kind described as scented, ultra or color-safe.
• Add 8 drops of bleach per gallon of water
• Shake or stir, then let it stand for 30 minutes
• For disinfected water, a slight chlorine taste or smell is normal.

Boiling Water

To treat water by boiling it:

• Bring a pot full of water to a rolling boil.
• Maintain that boil for a minimum of 3 to 5 minutes in order to kill bacteria.
• After the water cools, put it in a sealed container and shake it – this shaking will add oxygen back to the water and improve its taste.

*Additional Notes on Disinfecting Water
Your bleach may not be 5.25% chlorine, or the percentage may be unlisted. Use the information in the following table as a guide. (8 drops equals approximately 1/8 teaspoon.)

Double the amount of chlorine for cloudy, murky, or colored water or water that is extremely cold.

After disinfection, the water should have a slight chlorine odor. If not, repeat the dosage and allow the water to stand for an additional 15 minutes.

If the treated water has too strong a chlorine taste, allow the water to stand exposed to the air for a few hours, or pour it from one clean container to another several times.

Sources of water you CANNOT treat and drink include pool water and spa water. While this water is not appropriate for drinking, you can use it for flushing toilets or washing.