Health & Survival
15 minutes
Africa
How to purify water using the SODIS method
Why this matters
Over 2 billion people drink contaminated water. The SODIS method uses nothing but sunlight and a clear plastic bottle to kill bacteria and viruses — no fuel, no chemicals, no cost.
What you need
A clear PET plastic bottle (the kind used for soft drinks)
Clean or slightly cloudy water
Direct sunlight
A reflective surface (optional but helpful — corrugated iron works well)
These are everyday items. If you don’t have one, look for the closest alternative — the steps will tell you what to use instead.
How to do it
Follow these steps in order. Take your time. You’ve got this.
Fill a clear PET plastic bottle with water. If the water is very cloudy, let it settle first or filter it through a clean cloth.
Shake the bottle for 20 seconds with the cap on to increase oxygen in the water.
Place the bottle on a reflective surface in direct sunlight — a corrugated iron roof works very well.
Leave it for a minimum of 6 hours in full sunlight, or 2 days if the sky is more than 50% cloudy.
The water is now safe to drink. Store in a clean, covered container and do not touch the inside.
Your one thing today
Find a clear plastic bottle today and set one up in sunlight as a practice run so you know the process when you need it.
Don’t wait for the perfect moment. Do this one thing now, even if it’s small.
Come back tomorrow
A new skill will be waiting for you tomorrow. Or if you’d like to keep learning today, explore the full library.