How To Purify Water Using Only the Sun

How To Purify Water Using Only the Sun

You can live for weeks without food, but your body will only last a few days without water (especially in hot weather conditions). So if the unthinkable happens when you’re nowhere near your survival stash, what will you do? Will you be able to survive without your water filters?

You can purify water by boiling it, but you probably don’t carry a pot around with you all the time. Fortunately, if you have a plastic water bottle in your vehicle, you can collect water from various sources and use the sun to purify it. Here’s how.

SUNLIGHT IS A NATURAL PURIFIER

Sunlight is a natural disinfectant and can purify water. More specifically, the UV rays emitted from sunlight can kill the following germs and bacteria after full exposure for six hours:

  • Rotavirus
  • Escherichia coli
  • Salmonella
  • Giardia
  • Campylobacter jejuni
  • Vibrio cholera
  • Cryptosporidium (this one requires 10 hours of sun exposure for purification)
  • Yersinia enterocolitica
  • Shigella flexneri

These bad guys are commonly found in some water sources and can be life-threatening if you consume them. That’s why water purification is so essential when you’re in a survival situation.

HOW TO USE THE SUN TO PURIFY YOUR WATER

You can use any clear soda or water bottle to purify water with sunlight. However, it’s best to use a plastic bottle that is no larger than 2 liters. The higher the volume of water within the bottle, the less effective sunlight purification will become. This is because the sun’s UV rays lose 50% effectiveness when they have to penetrate a depth of approximately 0.5 inches in moderately cloudy water.

For best results, just use a regular-sized water bottle or soda bottle for your water purification needs. If you’re really lucky, you’ll have more than one lying around and can purify them all at once so you have more fluids to keep you hydrated. Follow these steps to purify water in your water bottles.   

STEP 1: LOCATE A WATER SOURCE

Before you can purify water, you have to find it. Ideally, you’ll be able to locate a relatively reliable water source, such as a stream or river. But depending on where you are, a puddle may be the best you can do. If you believe a source may be full of toxic chemicals, look elsewhere. UV rays won’t get rid of chemicals in your water bottle.

STEP 2: FILL THE BOTTLE UP

Once you’ve discovered a source of water that seems somewhat safe, put a piece of cloth (from your shirt, a bandana, etc.) over the opening of the water bottle and hold it in place. Then fill the bottle with water. The piece of cloth will help filter out excess sediment. Once the bottle is full, put the lid back on.

STEP 3: LAY THE BOTTLE DOWN IN FULL SUN

Find a spot where you can place the water bottle in full sun for at least six hours. Lay the bottle down so the sun can hit the water at the ideal angle. On a mildly cloudy day or a day with full sun, you should only need six hours of sunlight exposure. In very cloudy conditions (when the sun is behind clouds more often than not), you should plan on purifying your water over several days.

Don’t worry about the temperature. It doesn’t matter whether it is hot or cold, as long as your water is exposed to sufficient sunlight.

ENJOY YOUR PURIFIED WATER

Now that you know how to purify water using only sunlight, make sure you keep a water bottle with you at all times. You never know when you might need to rely on it for water collection and purification.

Do you have other reliable ways to purify water in a pinch?

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