Water is the single most critical prep you can make. The human body can survive three weeks without food. It cannot survive three days without water. Yet most people who start prepping put food storage first and treat water as an afterthought.
This guide fixes that prioritisation error with a complete, practical guide to emergency water storage.
How Much Water Do You Actually Need?
The standard recommendation is one gallon (approximately 3.8 litres) per person per day. This covers drinking (~2 litres), basic cooking (~0.5 litres), and minimal hygiene (~1.3 litres).
This is the minimum. In hot weather, physical exertion, or illness, requirements increase. A safer target is 1.5 gallons (5.7 litres) per person per day.
For a two-week supply:
- 1 person: 14 gallons minimum / 21 gallons recommended
- 2 people: 28 gallons minimum / 42 gallons recommended
- 4 people: 56 gallons minimum / 84 gallons recommended
- Per medium dog: add 7-10 gallons
- Per cat: add 2-3 gallons
The Best Water Storage Containers
- Food-grade 7-gallon water storage containers ($15-20 each): Best option for most households. Stackable, purpose-built, BPA-free, and easy to handle when full (58 lbs). Brands like WaterBrick and Aqua-Tainer.
- WaterBOB bathtub bladder ($25-35): Holds up to 100 gallons in your bathtub. Takes up virtually no everyday storage space. Excellent for apartment preppers.
- 55-gallon water barrels ($50-80): For larger households or those with storage space. Heavy when full (458 lbs) — require a pump to access.
- Repurposed 2-litre bottles (free): Work well for short-to-medium term storage. Milk jugs do not — protein residue cannot be fully removed.
How to Fill and Store Your Water Supply
- Clean containers with unscented dish soap, rinse thoroughly
- Fill with tap water from the cold tap
- For non-purpose-built containers, add 8 drops of unscented liquid chlorine bleach per gallon
- Seal tightly
- Label each container with the fill date and a “replace by” date 12 months from now
Storage conditions:
- Away from direct sunlight
- Away from heat sources
- Away from chemicals, cleaning products, and fuel
- Off the ground in flood-risk areas
How Long Does Stored Water Last?
- Commercial bottled water (sealed): 1-2 years per label
- Tap water in purpose-built containers: 1 year before rotating
- Tap water in repurposed bottles with bleach treatment: 6 months
Set a calendar reminder to rotate water annually.
Water Purification Backup
- Purification tablets (Potable Aqua): ~$8-10 per box of 50 tablets. Wait 30 minutes before drinking.
- Filter straw (LifeStraw or Sawyer Mini): Filters water from any freshwater source. Does not remove chemical contamination or salt.
- Boiling: Most reliable method. Rolling boil for at least one minute.
Finding Water in an Emergency
- Drain your home’s hot water tank
- Use the water in toilet cisterns (the tank — this is clean water)
- Collect rainwater
- Check local emergency services for water distribution points
Avoid: floodwater, standing water near industrial sites, water with unusual colour or smell.