5 Ways to Purify Water Without a Filter

Your expensive ceramic filter just cracked in a freeze. You are thirsty, and the only water source is a murky pond. What do you do? Filtration is great, but sterilization is mandatory. Here are five ways to kill the bugs without a pump.

1. Boiling (The Gold Standard)

Boiling kills everything. Viruses, bacteria, protozoa—nothing survives.

• Method: Bring water to a rolling boil.
• Time: 1 minute (at sea level) or 3 minutes (above 6,500 ft elevation).
• Pros: 100% effective.
• Cons: Uses valuable fuel; takes time to cool down.

2. Bleach (The Household Hero)

Plain, unscented household bleach (Sodium Hypochlorite) is a powerful disinfectant.

• Ratio: 2 drops per liter (or 8 drops per gallon) for clear water. Double it for cloudy water.
• Wait Time: Stir and let sit for 30 minutes. You should smell a faint chlorine scent. If not, repeat.
• Pros: Cheap, easy to find in urban scavenging.
• Cons: Doesn't remove chemicals; tastes like pool water; limited shelf life (bleach degrades in 6-12 months).

3. SODIS (Solar Disinfection)

Using the sun's UV rays to kill pathogens.

• Method: Fill a clear PET plastic bottle (like a soda bottle) with water. Lay it in direct sunlight on a reflective surface (tin roof) or rock.
• Time: 6 hours in full sun (or 2 days if cloudy).
• Pros: Free; requires only a plastic bottle.
• Cons: Unreliable on cloudy days; does not work with murky water (UV can't penetrate).

4. Calcium Hypochlorite (Pool Shock)

This is the "Prepper's Bleach." It is a powder used for pools.

• Shelf Life: 10+ years (unlike liquid bleach).
• Method:
  1. Make a stock solution: Dissolve 1 heaping teaspoon of granular pool shock (70% av. chlorine) in 2 gallons of water. Do NOT drink this!
  2. Use the stock solution: Add 1 part stock solution to 100 parts water to treat drinking water.
• Warning: Highly corrosive in powder form. Handle with care.

5. Distillation (The Nuclear Option)

Boiling water and capturing the steam.

• Method: Put a pot on a fire. Put a smaller bowl inside the pot (floating or on a stand). Invert the pot lid so the handle points down.
• Process: As water boils, steam hits the lid, condenses, and runs down the handle to drip into the small bowl.
• Pros: Removes everything—including salt, heavy metals, and radiation. The only way to drink ocean water.
• Cons: Uses a massive amount of fuel for very little water.

Conclusion

Always carry a filter. But carry a lighter (to boil) and a dropper of bleach as your Plan B and Plan C.