Emergency Water Storage: How Much and How to Store It

How much water to store

FEMA and the CDC recommend storing at least 1 gallon of water per person per day. That covers drinking (about half a gallon) and basic sanitation needs (the other half). The minimum recommendation is a 3-day supply, but FEMA encourages a 2-week supply for maximum preparedness.

Household Size	3-Day Minimum	1-Week Supply	2-Week Supply
1 person	3 gallons	7 gallons	14 gallons
2 people	6 gallons	14 gallons	28 gallons
4 people	12 gallons	28 gallons	56 gallons
6 people	18 gallons	42 gallons	84 gallons

Increase your stored amount if you live in a hot climate (dehydration risk increases water needs to 1.5-2 gallons per person per day), have young children, nursing mothers, or anyone with a medical condition that requires extra hydration. Pets need roughly 1 gallon per day for dogs and 0.25 gallons per day for cats.

Choosing the right storage containers

Commercial water jugs (3-7 gallons)

These are the easiest option for most households. Food-grade HDPE plastic (look for the recycling number 2) is the standard material. Stackable designs save space. Pre-filled commercial water has a shelf life of 1-2 years from the bottling date, though water itself does not expire. The concern is the container degrading or allowing contaminants over time.

55-gallon drums

The most space-efficient option for storing large volumes. A single 55-gallon drum covers a family of four for nearly two weeks. Use only food-grade blue polyethylene drums (never repurposed chemical drums). Fill with municipal tap water (already treated with chlorine). Add water preserver concentrate (sodium hypochlorite based) to extend shelf life to 5 years without rotation. A drum weighs approximately 460 pounds when full, so place it in its permanent location before filling.

Water bricks and modular containers

Stackable, portable containers in 1.6 to 3.5 gallon sizes. More expensive per gallon than drums, but they are easy to carry, fit in closets and under beds, and can be distributed around your home. Good for apartments or homes without space for a 55-gallon drum.

WaterBOB and bathtub bladders

A bathtub liner that holds up to 100 gallons of water. Designed to be filled when a storm warning is issued, not for long-term storage. Useful as a supplement to your main storage when you have advance notice of a potential emergency.

Where to store water

• Keep containers in a cool, dark location. Heat and sunlight accelerate plastic degradation and can promote bacterial growth.
• Store off the concrete floor if possible (use pallets or shelving). Concrete can leach chemicals into plastic containers over time.
• Avoid storing near gasoline, pesticides, or chemicals. Vapors can permeate some plastic containers.
• Garage storage is acceptable if temperatures stay between 40-70°F. Avoid locations where water could freeze (expansion can crack containers).
• Distribute some water storage in different locations in your home in case one area becomes inaccessible.

Water rotation schedule

How often you need to replace stored water depends on the container and treatment:

Container Type	Rotation Frequency	Notes
Store-bought bottled water	Check expiration date	Typically 1-2 years from bottling
Self-filled jugs (no preservative)	Every 6 months	Municipal chlorine dissipates over time
Self-filled jugs (with preservative)	Every 5 years	Follow preservative manufacturer instructions
55-gallon drum (with preservative)	Every 5 years	Use a pump or siphon to drain; too heavy to pour

Emergency purification methods

When stored water runs out, you need a way to make water from natural sources safe to drink. These methods handle biological contaminants (bacteria, viruses, parasites) but do not remove chemical contaminants, heavy metals, or PFAS.

Boiling

The CDC recommends bringing water to a rolling boil for 1 minute (3 minutes above 6,500 feet elevation). This kills all pathogenic bacteria, viruses, and parasites. It is the most reliable purification method when fuel is available. Let water cool before storing in clean containers.

Portable pump filters

Filters like the Sawyer Squeeze, LifeStraw, and Katadyn Pocket filter remove bacteria and protozoa down to 0.1-0.2 microns. Most do not remove viruses (less of a concern in US water sources). Flow rates range from 0.5-2 liters per minute. These are excellent for filtering water from streams, lakes, or collected rainwater.

Chemical treatment

Chlorine dioxide tablets (such as Aquamira or Potable Aqua) kill bacteria, viruses, and Giardia. Treatment time is 30 minutes for most tablets, 4 hours for Cryptosporidium. Household bleach (unscented, 6-8.25% sodium hypochlorite) can also be used: add 8 drops per gallon, mix, and wait 30 minutes. The water should have a slight chlorine smell after treatment.

UV purifiers

Battery-powered UV purifiers (like the SteriPEN) kill bacteria, viruses, and protozoa by disrupting their DNA. Treatment takes 60-90 seconds per liter. Requires clear water (pre-filter if turbid) and charged batteries.

What emergencies require water storage

• Boil water advisories: Issued when bacterial contamination is suspected. Can last hours to weeks. See your city\'s history on CheckMyTap.
• Natural disasters: Hurricanes, earthquakes, floods, and winter storms can disrupt water treatment and distribution for days or weeks.
• Infrastructure failures: Water main breaks, treatment plant malfunctions, and power outages can interrupt service without warning.
• Contamination events: Chemical spills or algal blooms can make tap water unsafe even after boiling.

The key is having water stored before you need it. By the time an emergency is announced, store shelves are typically empty within hours. A well-maintained home water supply means you are not competing for bottled water at the last minute.