Water18 min readUpdated January 2025

Emergency Water Storage Guide 2025

Water is your most critical prep. Learn how much you need, the best storage containers, purification methods that actually work, and lessons from real emergencies like the Texas freeze and Hurricane Maria.

1

How Much Water Do You Need?

FEMA, CDC, and Red Cross all recommend 1 gallon per person per day as the minimum. This breaks down to roughly 0.5 gallons for drinking and 0.5 gallons for cooking and basic sanitation.

Key Takeaway
The official minimum is a 3-day supply, but most agencies now recommend 14 days (2 weeks) for realistic emergency planning. Real disasters like Texas 2021 showed 3 days is woefully inadequate.

Quick Reference

14 gal
1 person, 2 weeks
56 gal
Family of 4, 2 weeks
120 gal
Family of 4, 1 month

Special Considerations

Hot Climates

Increase by 50-100%. Heat and physical exertion dramatically increase water needs.

Pregnant/Nursing

Need additional water beyond the standard gallon per day.

Sick Individuals

Fever, vomiting, or diarrhea increase hydration needs significantly.

Pets

1 oz per pound of body weight daily. A 60-lb dog needs 0.5 gallon/day.

WHO Standards
The World Health Organization sets higher standards: 4 gallons (15 liters) per person per day for full hygiene needs. The 1 gallon minimum is survival-level only.
2

Storage Container Options

5-7 Gallon Stackable Jugs

The most practical size for most homes—portable when full, affordable, and easy to rotate.

Recommended

Reliance Aqua-Tainer

7 Gallon

Price~$25
Cost/gal$3.57
Best budget pick
Excellent value

Reliance Rhino

5.5 Gallon

~$20

Cost/gal$3.64
Toughest in class
Stackable

Scepter Military Can

5 Gallon

$25-45

Fill hole4 inches
Military-grade
Very durable

55-Gallon Drums

The workhorse of serious preppers. Cost-effective at scale.

Recommended

Legacy 55-Gallon

FDA-approved HDPE

$70-90

Cost/gal$1.27-1.64
Dimensions22" × 28" × 30"
Full weight~460 lbs
Cost-effective
Durable
Fits through doors
Very heavy when full
Requires pump

IBC Tote

275-330 Gallon

Under $100 used

Cost/gal$0.36
Full weight~2,347 lbs
Best $/gallon
Ball valve discharge
Forklift accessible
Requires significant space
Very heavy

WaterBOB (Bathtub Bladder)

Emergency option that uses your bathtub. ~$35 for 80-100 gallons. Keeps water fresh for 16 weeks.

Pro Tip
Best for: Hurricanes, ice storms—emergencies with advance warning. Not suitable for earthquakes (no warning time). Cannot be moved when full.
Containers to AVOID
  • Milk jugs - biodegradable, retain bacteria
  • Previous chemical containers - bleach, pesticides
  • Non-food-grade plastics
  • Glass containers - breakable, heavy
  • Non-stainless steel - corrodes
3

Water Treatment & Preservation

How Long Does Stored Water Last?

Key Takeaway
Water itself doesn't expire—it can only become contaminated. Properly stored water in the right containers can last indefinitely.
6 months
Without treatment (rotate)
5 years
With water preserver
2-5 years
Commercial bottled

Water Preserver Products

Recommended

Water Preserver Concentrate

7C's, H2O ResQ

$20-40

Duration5 years
Coverage275 gal per 2oz bottle
CertificationEPA approved

Aquamira

Chlorine Dioxide

$20-30

Duration5 years
TypeTwo-part system
No bleach taste

Storage Best Practices

  • 1Temperature: 50-70°F ideal. Heat accelerates degradation.
  • 2Light: Keep in dark location, away from direct sunlight.
  • 3Chemicals: Store away from gasoline, pesticides, solvents.
  • 4Concrete floors: Use a barrier (wood, cardboard)—chemicals can leach through plastic.
Cistern Size Calculator
Calculate storage capacity for your needs
4

Purification Methods

Gravity Filters

Best for home base stations—no pumping, no electricity, large capacity.

Berkey

Big/Royal

$660-730

Capacity22,000L per filter pair
Replacement$310/pair
Gold standard
Huge capacity
Not NSF certified
Expensive
Recommended

Phoenix

Berkey Alternative

$355-435

Capacity20,000L per pair
Replacement$140/pair
Warranty10 years (vs Berkey 1 year)
Better value
Longer warranty
100-day trial

Portable Filters

Recommended

Sawyer Mini

~$26

Capacity100,000 gallons
Pore size0.1 microns
Huge capacity
Versatile (inline, gravity, squeeze)
Field cleanable
Does NOT remove viruses

LifeStraw

~$12

Capacity1,000 gallons only
Pore size0.2 microns
Very cheap
Low capacity
Not field cleanable
Slow, clogs easily
Filters Don't Remove Viruses
Neither Sawyer nor LifeStraw removes viruses. In areas with viral contamination risk (flood water, developing countries), combine filtration with chemical treatment or UV.

Chemical Treatment

Household Bleach (5.25-6.25% unscented)

Clear water: 8 drops per gallon
5 gallons: 11 drops
55 gallons: 1¾ teaspoons
Wait time: 30 minutes minimum

What Removes What?

FeatureBoilingBleachFiltersUVDistill
Bacteria
Viruses
Protozoa
Heavy MetalsPartial
ChemicalsPartialPartial
Water Purification Calculator
Calculate treatment needs for your water supply
5

Rainwater Collection

Legality by State

Rainwater collection is legal in most states. Only Colorado (110 gallon limit, outdoor use only) and Utah (registration required over 100 gallons) have significant restrictions.

States that actively encourage collection with incentives: Arizona, California, Florida, Hawaii, Texas, and others.

Collection Potential

Gallons = Roof Area (sq ft) × Rainfall (inches) × 0.623
Example: 2,000 sq ft × 1" rain = 1,246 gallons potential
With 80% efficiency: ~1,000 gallons actual
Rule of Thumb
1 inch of rain on 1,000 sq ft roof = 600+ gallons
Rainwater Collection Calculator
Estimate collection potential from your roof

Roof Materials

Best: Metal

90%+ efficiency, doesn't absorb water

OK: Asphalt Shingles

Use first-flush and filter

Avoid: Wood/Tar

Treatment chemicals, toxins

6

Alternative Water Sources

Your Water Heater

Often overlooked: your water heater holds 30-50 gallons of potable water.

Access via the drain valve at the bottom. Already filled and doesn't count against storage space.

Well Water

Consider a hand pump for grid-down scenarios.

Simple Pump: Up to 325 feet depth, $800-1,500+. Standard hand pumps only work to 25-35 feet.

Natural Water Source Myths
  • Myth: Swift-moving water is safe. Reality: It's not.
  • Myth: Cold water is clean. Reality: Temperature doesn't indicate safety.
  • Always purify water from streams, rivers, lakes, and ponds.
7

Real-World Case Studies

Texas Freeze 2021 (Winter Storm Uri)

February 10-27, 2021

Impact

  • • 1.4+ million lost water service
  • • 12 million under boil-water advisories
  • • Austin lost 325 million gallons from burst pipes
  • • Some without water for 7+ days

What People Did

  • • Collected gutter water to flush toilets
  • • Shared showers with friends
  • • Used bottled water for washing
  • • Paid $200+ for hotel rooms
Lesson: 3 days isn't enough. Plan for 7-14 days minimum.

Hurricane Maria - Puerto Rico (2017)

September 2017 - August 2018

Impact

  • • 44% without water after 1 week
  • • 14% still without water 3 months later
  • • Boil water advisories lasted months

What Failed

  • • Warehouses of bottled water left to rot
  • • Government distribution failed
Lesson: You cannot rely on government distribution. Plan for weeks to months.

Flint Water Crisis (2014-2018)

18 months of contaminated tap water

Impact

  • • 140,000 people exposed to lead
  • • Lead levels up to 13,000 ppb
  • • 12 deaths from Legionnaires' disease
Lesson: Never assume tap water is safe. Aging infrastructure is a real threat.
8

Budget Setups

Budget Setup

Under $100

~$77
  • Two 7-gallon Aqua-Tainers$50
  • LifeStraw filter$12
  • Bleach for treatment$5
  • Storage bags$10

Coverage: 14 gallons = 2 weeks for 2 people or 1 week for 4

Recommended

Medium Setup

$100-500

~$290
  • Two 55-gallon drums$140-180
  • Water Preserver (5-year)$20
  • Sawyer Squeeze filter$40
  • Reliance Rhino (portable)$20
  • Bottled water cases$30

Coverage: 120+ gallons = 4+ weeks for family of 4

Comprehensive Setup

$500+

~$1,000
  • Six 55-gallon drums$420-540
  • Water Preserver$30
  • Phoenix gravity filter$355
  • Sawyer Squeeze backup$40
  • Two 7-gallon portable$50
  • WaterBOB$35

Coverage: 344+ gallons = 11+ weeks for family of 4

9

Frequently Asked Questions

How long can water be stored?
Water doesn't expire—only the container degrades or contamination occurs. With proper treatment and storage, water can last indefinitely. Without treatment, rotate every 6 months. With water preserver, 5 years.
Can I drink water from my water heater?
Yes. Your water heater contains 30-50 gallons of potable water accessible via the drain valve at the bottom. This is often overlooked emergency storage.
What's the minimum I should store?
1 gallon per person per day for at least 14 days (not the outdated 3-day recommendation). Real emergencies like Texas 2021 and Puerto Rico 2017 showed 3 days is woefully inadequate.
Do I need both filtration and purification?
Yes, ideally. Filtration removes sediment, particles, and some chemicals. Purification (boiling, UV, chemicals) kills organisms. For complete protection, use both.
Can I collect rainwater in my state?
Legal in most states. Only Colorado and Utah have significant restrictions. Many states like Arizona, California, and Texas actively encourage it with incentives.
How do I know if my stored water is still safe?
Check for cloudiness, odor, buildup around edges, or algae growth. When in doubt, treat before use. Flat taste can be fixed by aerating (pouring between containers).

Related Calculators

Last updated: January 2025. Prices and availability change—verify current pricing before purchasing. Always follow local regulations for rainwater collection and well installation. This guide is for educational purposes.