How much water should I store for an emergency?

FEMA recommends storing at least 1 gallon of water per person per day for at least 3 days, but ideally 2 weeks. A family of 4 needs 56 gallons for 2 weeks. Store water in food-grade containers (BPA-free, blue 55-gallon barrels or 5-gallon jugs). Rotate stored water every 6-12 months. For sanitation, add extra water — total recommended: 1.5-2 gallons per person per day including cooking and hygiene. In a disaster, also plan for pets: dogs need 1 ounce of water per pound of body weight daily. Water purification tablets (iodine or chlorine) and a Sawyer Squeeze or LifeStraw filter extend your options significantly.

How much food should I store for emergency preparedness?

Emergency food storage guidelines: FEMA minimum = 3-day supply; recommended = 2-week supply; prepper standard = 3-month to 1-year supply. Caloric needs: adults need 2,000-2,500 calories/day; children 1,200-1,800; active adults 2,500-3,000. For a 2-week supply for a family of 4: approximately 112,000 calories total = roughly 56 lbs of rice + beans (4,000 cal/lb combined), canned goods, freeze-dried meals. Freeze-dried food (Mountain House, Augason Farms) lasts 25-30 years. Mylar bag + oxygen absorber storage extends dry goods (rice, oats, pasta) to 25+ years. Rotate canned goods using FIFO (first in, first out).

How do I calculate generator size for my home?

Generator sizing formula: add up wattage of essential appliances. Key loads: refrigerator (150-400W running, 700-1,200W starting); window AC (1,000-1,500W running); central AC (2,000-5,000W running); sump pump (750-1,500W running, 2,000-3,000W starting); well pump (750-1,500W, 3,000-5,000W starting); furnace fan (400-800W); lights (LED 5-15W each). Starting wattage can be 2-3x running wattage — size for peak starting load. A 7,500W generator handles most essentials; 12,000-15,000W runs central AC + well pump simultaneously. Portable inverter generators (2,000-4,000W) quietly power refrigerator + lights + phone charging. Whole-home standby generators (20-22kW) run everything automatically.

Water Purification Calculator

Calculate water purification capacity and supplies needed for emergencies. Compare treatment methods and plan your backup water supply.

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Calculate Water Purification Needs

Number of People

Duration (days)

Primary Water Source

Preferred Treatment Method

Considerations

Have fuel for boiling water Have backup power (for UV devices) Need portable/lightweight option Water source may be cloudy/turbid

Understanding Water Purification

Clean water is the most critical emergency supply. While storing water is ideal, you may need to purify additional water from alternative sources. Different purification methods address different contaminants:

Method	Bacteria	Viruses	Parasites	Chemicals
Boiling	Yes	Yes	Yes	No
Chlorine/Bleach	Yes	Yes	Partial	No
Iodine Tablets	Yes	Yes	Partial	No
UV Light	Yes	Yes	Yes	No
Filter (0.2 micron)	Yes	Most	Yes	Some
Carbon Filter	No	No	No	Yes

1 gallon

Minimum water per person per day for drinking and basic hygiene - plan purification capacity accordingly

Purification Methods Compared

Boiling

Pros: Most reliable, kills all pathogens, no supplies needed beyond fuel

Cons: Requires fuel, time-consuming, doesn't remove chemicals

How: Bring to rolling boil for 1 minute (3 minutes above 6,500 ft elevation)

Gravity/Pump Filters

Pros: Fast, high capacity, removes particulates, no fuel needed

Cons: Expensive upfront, filters need replacement

Capacity: 1,000-100,000+ gallons depending on model

Chemical Treatment (Tablets/Bleach)

Pros: Lightweight, inexpensive, long shelf life

Cons: Wait time, taste, less effective on parasites

Bleach ratio: 8 drops per gallon (or 1/8 tsp), wait 30 minutes

UV Treatment

Pros: Fast, effective, no chemicals

Cons: Requires batteries/power, doesn't work on cloudy water

Pre-Treatment for Cloudy Water

If water is visibly cloudy or turbid:

Let settle for several hours
Pour clear water off the top
Filter through cloth or coffee filter
THEN use your purification method

Frequently Asked Questions

What's the best water purification method for emergencies?

A multi-method approach is best. Store clean water as your primary supply. Keep a gravity filter (like Berkey or LifeStraw) for high-capacity purification. Have chemical tablets as backup. Know how to boil water if other methods fail.

How long do water purification tablets last?

Unopened tablets typically last 4-5 years. Once opened, use within 1 year. Iodine tablets have shorter shelf life than chlorine dioxide. Store in cool, dry place away from light.

Can I use pool chlorine to purify water?

No. Pool chemicals contain stabilizers and other additives unsafe for drinking water. Use only plain, unscented household bleach (5-9% sodium hypochlorite) or products specifically designed for water purification.