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How much water to store for an emergency

By the Protocol Survival team · Based on Ready.gov, CDC and EPA guidance · Updated October 2026

Water is the first thing that becomes a problem in a long outage. Many homes rely on electric pumps (municipal booster stations or a private well pump), and water systems can issue boil-water notices after storms. You can go weeks without food. You can't go more than a few days without water.

Household water chart

Store more if: you live somewhere hot (Texas, Arizona, Florida summers), someone is pregnant, nursing or sick, or you have pets. Dogs and cats need water every day too — add them to your count.

Best containers for storing water

• Unopened commercially bottled water. The simplest option. Keep it in its original packaging and observe the date.
• Food-grade water containers (5–7 gallon jugs, stackable bricks, or 55-gallon drums if you have floor space and a pump to get water out).
• Clean 2-liter soda bottles work for small spaces and apartments.
• Avoid milk and juice jugs. They're hard to clean and the plastic breaks down. Never reuse containers that held chemicals.

Store water in a cool, dark place away from gasoline, pesticides and cleaning products. Plastic can absorb vapors.

How often to rotate stored water

Ready.gov recommends replacing water you bottled yourself every six months. A simple habit: swap it when you change your clocks for daylight saving time, and write the fill date on each container with a marker.

Hidden water already in your home

• Water heater tank: typically 30–50 gallons. Turn off the power or gas first, open a hot-water faucet to let air in, then drain from the valve at the bottom. Let it cool before using.
• Toilet tank (not the bowl): usable for flushing as-is; only drink it after disinfecting, and never if the tank has a chemical cleaner in it.
• Ice and canned fruits/vegetables: contain liquid you can use.
• The bathtub: when a storm is forecast, fill tubs and clean containers while the water pressure is still on. Use tub water for flushing and washing.

How to make water safe to drink

If your stored water runs out or your utility issues a boil-water advisory (what you can and can't do), follow this order: settle → filter → disinfect.

Option 1: Boil (most reliable)

Let cloudy water settle, then filter it through a clean cloth or coffee filter. Bring it to a rolling boil for 1 minute (3 minutes above 6,500 feet). Let it cool and store it in clean, covered containers.

Option 2: Unscented household bleach

Use regular, unscented chlorine bleach (no "splash-less," scented or color-safe products). Check the label for the concentration:

Stir and wait at least 30 minutes. The water should have a slight chlorine smell. If it doesn't, repeat the dose and wait another 15 minutes. Don't "add extra to be safe" — the right dose matters.

Option 3: Filters

Portable filters remove bacteria and parasites, but many do not remove viruses. Look for a filter tested to NSF/ANSI standards, and if in doubt, filter and then disinfect.

Your water checklist

• Count people and pets, multiply by 1 gallon per day, and pick your target (3 days → 2 weeks)
• Buy or fill food-grade containers and label each one with the date
• Store them in a cool, dark place away from chemicals
• Keep unscented bleach and a medicine dropper with your supplies
• Learn where your water heater's drain valve and shutoff are
• Set a reminder to rotate water every six months

Related guides

• Power outage checklist: before, during and after
• How long food lasts in the fridge without power
• How to make a family emergency plan