Storing & Purifying Emergency Water
After storms, floods, earthquakes, power failures or pipe breaks, tap water can stop flowing or become unsafe. People can survive weeks without food but only days without water. A small supply stored in advance, plus knowing how to make questionable water safe, protects your household.
- Households
- Families with Children
- Older Adults
- Pet Owners
- Workplaces
How much to store
- Plan on at least 1 gallon of water per person per day, for drinking and basic hygiene.
- Store at least a 3-day supply as a minimum for evacuation or short outages, and a 2-week supply if you can, for sheltering at home. See Emergency Kit and Family Emergency Plan.
- Increase the amount for hot weather, nursing mothers, pregnant women, sick people and those on certain medicines. Children and older adults can dehydrate quickly. See Extreme Heat at Home.
- Add water for pets (roughly 1 gallon per day for a large dog, less for small pets) and for cooking and cleaning if possible. See Pets & Emergencies.
- Keep a smaller portable supply in a go-bag and in the car. See Car Emergency Kit.
Choosing and filling containers
- Commercially bottled water is the simplest option. Keep it in the original, sealed containers in a cool, dark place, and use it by the printed expiration date.
- If you fill your own containers, use clean, food-grade plastic or glass containers with tight caps, such as new water storage containers or clean 2-liter soda bottles. Don't use containers that held milk or juice (hard to clean and can grow bacteria), or anything that held chemicals.
- Wash containers with dish soap and rinse well. Sanitize with a solution of 1 teaspoon of unscented household bleach per quart of water, swish for 2 minutes, then rinse with clean water.
- Fill with safe tap water from a public supply that's already treated, and seal tightly. Label with the fill date. If your water comes from a well or untreated source, treat it first. See Well Water.
- Use safe-sized containers you can carry and store; avoid very large, heavy containers on high shelves or places that could collapse.
- Don't store water in milk cartons, plastic grocery bags or containers that can break down. Don't use old, cracked or soft bottles.
Where and how long to store it
- Store in a cool, dark place away from sunlight, heat and household chemicals, gasoline and pesticides, since vapors can pass through plastic. See Household Chemicals.
- Don't leave water in a hot garage, attic or car, and keep it from freezing, which can crack containers.
- Replace home-filled water every 6 months (many guides say every 6 to 12 months), and check for cloudiness, odor or leaks. Commercial water follows the expiration date.
- Store some water in different places so you can reach it if part of the house is damaged.
- Consider water in a stackable, secured arrangement in earthquake and hurricane areas. See Earthquakes and Hurricanes & Floods.
Emergency sources of safe water inside your home
- Water heater tank (turn off the power or gas first and let it cool, close the water inlet valve, then drain from the tap at the bottom). See Water Heaters and Shutting Off Utilities.
- Pipes: water in the pipes after you shut off the main valve can be drawn by opening the highest faucet and then the lowest.
- Ice cubes and the melted ice of the freezer, and canned fruit and vegetable liquids.
- Do not drink water from swimming pools, hot tubs, toilet tanks that have cleaning tablets, radiators, water beds or flood water. See Hot Tubs and Pool & Water Safety.
Making water safe to drink
Follow local authorities' advice (boil water advisory or other notice). If told water is unsafe, use these methods on clear water. If water is cloudy, filter it through a clean cloth or let it settle first.
- Boiling is the most reliable: bring water to a rolling boil for at least 1 minute (3 minutes at elevations above about 6,500 feet), then cool and store in clean containers. Boiling kills germs but doesn't remove chemicals.
- Disinfecting with household bleach: use plain, unscented liquid bleach with 5 to 9 percent sodium hypochlorite and no added soaps or thickeners. Follow the amounts printed on the label or from the CDC for the strength of your bleach (for example, about 8 drops of 6 percent bleach per gallon of clear water), stir, and let stand at least 30 minutes. The water should have a slight chlorine smell; if not, repeat once and wait 15 more minutes.
- Purification tablets and portable filters: use products rated to remove or kill bacteria, viruses and parasites (look for NSF or EPA registration) and follow the label. A filter alone may not remove viruses.
- Don't use solar disinfection or home distillation unless you know the method. Chemical contamination (fuel, pesticides, sewage) can't be fixed by boiling or bleach. Seek an alternate source.
- Use safe water for drinking, brushing teeth, washing food, making ice, baby formula and washing dishes until the all-clear is given.
Water storage checklist
- I store at least 1 gallon per person per day, for at least 3 days (2 weeks if possible)
- Containers are food-grade, clean, sealed, labeled and kept in a cool, dark place
- I rotate home-filled water about every 6 months and use bottled water by its date
- I know how to use the water heater and pipes as emergency sources
- I know how to boil or disinfect questionable water
Standards & references
Last updated: