Water Purification Guide

The Importance of Water

In an emergency, your body’s need for water is immediate.

• Hydration Requirements: On average, a person needs a bare minimum of 500ml to 1 liter of water daily just to survive. For adequate health, men typically require about 3.7 liters (15.5 cups) and women about 2.7 liters (11.5 cups).
• The Survival Timeline: The human body can only go about two days without water before it begins to fail. Remember: you cannot ration water; you can only ration sweat.
• Sanitation Needs: Plan for an additional 1–2 gallons per person per day for washing and basic sanitation. While average daily usage is 80–120 gallons, emergency usage is significantly lower but still vital.

Identifying Water Contaminants

Understanding what is in your water is the first step toward purifying it. Roughly 51% of surveyed waterways in 2022 were found to be contaminated.

• Biological: Includes toxins, viruses, fungal spores, bacteria, and parasites like Giardia, Cryptosporidium, and E. coli.
• Chemical: Industrial waste, road spills (oil and fuel), herbicides, pesticides, and “forever chemicals” like PFAS.
• Heavy Metals: Lead, mercury, and other industrial byproducts (e.g., the Flint, Michigan crisis).
• Salt: Saltwater is not drinkable without specialized desalination equipment.

Water Purification Methods

Before purifying, look for clues: flowing water is generally better than stagnant water, and the color, smell, and opacity can indicate the level of contamination.

Boiling and Distillation

• Boiling: Bring water to a rolling boil for at least one minute. This denatures the proteins in most biological contaminants but does not remove chemicals or heavy metals.
• Distillation: Capturing steam and cooling it back into water. While effective, it may still carry over certain volatile chemicals.

Filtration
Filters use a physical barrier (membrane) to remove contaminants based on size.

• Micron Ratings: Most backpacking filters are 0.2 to 1 micron. To remove viruses, a 0.02-micron filter is required.
• Maintenance: Use a pre-filter (like a cloth or pool sock) to remove large particles, which can prolong the life of your main filter.

Chemical Purification

• Options: Common chemicals include bleach, iodine, ozone, and specialized products like Aquamira or Aquatabs.
• Usage: Ratios and wait times are critical; some chemicals require up to 4 hours to be fully effective. Do not “stack” different chemical types, as this can be dangerous.

Reverse Osmosis

• Pros: Improves taste and removes lead, chlorine, fluoride, and PFAS. It is also one of the few ways to desalinate water.
• Cons: These systems are expensive, require power, and are generally not portable.

Potable Water Storage

Once your water is purified, you must store it correctly to prevent re-contamination.

• Containers: Use airtight, opaque containers to prevent algae growth. Options include Jerry cans, 55-gallon drums, WaterBricks, or IBC totes.
• Weight Factors: Water is heavy, weighing approximately 8.33 lbs per gallon.
• Maintenance: Cycle your stored water on a regular schedule and treat it for long-term storage if necessary.

Recommended Resources and Gear

For those building their emergency kits, the following items and resources are recommended:

• Filters: Sawyer Water Filter Kits, LifeStraw bottles, or countertop filters.
• Storage: WaterBrick containers or 55-gallon drums.
• Treatment: Aquatabs, Aquamira, or water preserver concentrates.
• Further Reading: Visit Cana Provisions Water Plan for detailed guides.