Water is a top priority as you can’t survive beyond three days without it. Unclean drinking water can have harmful bacteria, protozoa, cryptosporidiums, viruses, and chemicals in it. Waterborne illnesses can cause flu-like symptoms, watery diarrhea, loss of appetite, substantial loss of weight, bloating, increased gas, nausea, fever, chills, coughing, muscle aches, cramps, blurred vision, difficulty breathing, seizures, paralysis, and even death. You don’t want to mess around with water that has not been purified.


Take the necessary precautions and purify your water before you drink it. Simple rules like drinking clear water or water that is moving quickly don’t always apply. Dead animals and feces can be in the water supply further up stream. Even water supplies that have been known to be safe can become contaminated at a later date.

These are the most common methods to purify water in survival or backpacking setting.

iodine tablets
Iodine Tablets

Pros
Light weight
Dependable
Easy to use

Cons
Tastes like Iodine
Results aren’t instant


chlorine dioxide
Chlorine Dioxide Tablets

Pros
Light weight
Dependable & Easy
Better Tasting Than Idodine

Cons
Doesn’t Filter Particles
Limited to 30 Quarts

MSR Miox Pen
Chlorine Pens – MSR MIOX Purifier

Pros
Compact & Small
No Filters to Worry About
Unlimited Uses

Cons
Requires Batteries & Salt
Can leave chlorine taste

water bottle purifier
Water Bottle Purifiers

Pros
Self Contained Filter and Bottle
No Wait Time or Setup
Fast Drinking

Cons
Difficult for large quantities
Average Filtering (but still safe)

Bottle and Filter Combined
Pump & Bottle – Lifesaver 4000

Pros
Self Contained Filter and Bottle
Easy setup & usage
Advanced filtering

Cons
Bulky
Difficult for large quantities

filter straw
Water Filter Straws

Pros
Super small & light
Easy to use
Fast drinking

Cons
Difficult for large quantities
Average filtering (but still safe)

steripen
Ultra Violet Light – SteriPen

Pros
Small & light
Easy to use
No aftertaste

Cons
Requires batteries
Leaves particles in water

pump miniworks filter
MSR Pump Filter

Pros
Can make large quantities
Fits onto Nalgene bottles
Filters out particles

Cons
Longer Setup Time
Can require maintenance

titanium pot for boiling water
Pot to Boil Water

Pros
Proven method
No filters to replace
Dependable

Cons
Can take a long time
Requires a fire or stove

Tips for Improving Taste

  • If the water is murky or cloudy first filter the water through a clean cloth. Coffee filters are also very good to fix murky water.
  • Try to find water that is free running and already clear. Avoid stagnant water. Avoid water that has been contaminated with animal or human waste.
  • If water tastes like iodine, chlorine, or is stale, pour the water between two containers or shake the water in a bottle to add oxygen to the water.
  • Vitamin C tablets can help improve the chlorinated taste that is present in water sometimes. Because chlorine is a base the acid helps adjust the PH level and adds flavor.

Survival Purification Methods

Sterilize with Sunlight – Ultraviolet rays can kill micro organisms if exposed for enough time. You will need a clear water bottle. Remove any dirt and labels found on the bottle. Fill the bottle 3/4 the way full and shake it for 30 seconds. Fill the bottle the rest of the way, making sure the water is clear with no particles in it. If the water is cloudy or murky this method will not work. Place the water bottle (no larger than 4″ in diameter) on a reflective surface for 6 hours on a sunny day. If there are clouds present it may require 48 hours or more to be effective. If dense clouds or rainy conditions are present this method will not work. Video

Solar Still & Evaporation Methods – A solar still uses moisture found in plants and in the soil and collects it. To make a solar still you will need a tarp, a cup, something to dig with, and a drinking tube. Dig a pit slightly smaller than your tarp. Add parts of live plants and other things that have moisture to the pit. In the middle of the pit place a cup to collect the distilled water. Place the tarp over everything and pin down the edges with heavy stones or logs. Place a rock in the middle of the tarp making sure to center the depression over the collection cup. As the water in the plants and in the soil evaporates it will collect on the tarp and drip into your cup. Drink the water from the cup periodically. The tarp can also act as a means to collect rain water as well. This method can remove salt from water as well if you are near the ocean.

Earth Filter – It is possible to make an earth filter using charcoal, sand, and grass. You will need a container like an old water bottle or birch tree bark folded into a cone. Add alternating layers of charcoal and sand with the grass on top. Filter the water through the container and into your collection cup. Personally I don’t trust this method and would only use it as a last resort.

Emergency Water Sources
Urine – It is possible to drink your urine twice in succession before it becomes toxic. Drinking urine a couple times will not harm you because it is sterile. There are some people that drink urine regularly for medicinal purposes.

Water that doesn’t need to be purified

Rain Water – Use a tarp, your coat, a poncho, or a tent’s rain fly to collect and store water. If water is running down a rock face you can lie a rope along one of the veins where the water is running. Use the end of the rope to guide the water into your water bottle. Even if the water is only dripping you’ll soon have gallons of clean water.

Melted Snow – It is not advisable to eat snow if you are lost in the winter. Eating snow will lower your core temperature and could put you at risk of hypothermia. Try to melt snow before drinking the water from it.

Spring Water – Hike to the top of a stream or look for areas where the water is coming from the ground or from a rock.

Morning Dew – Spread out your tarp or tent’s rain fly the night before. Dew will collect on the surface of these over night. In the morning gather the ends of the tarp making a pool at the bottom of the tarp for dew collection. Carefully unwrap the tarp and collect the water at the bottom. You can also use items of clothing to absorb dew. Once the clothing is wet wring out the moisture into your mouth or water bottle.

Wet Earth Water Extraction – If you are in an area that has a lot of water in the soil you can extract it using this method. You will need a long drinking tube and a shovel. Dig a deep hole in the ground. Add a layer of dry grass on the bottom of the hole. Place the end of your drinking straw on top of the pile of dry grass. Add another layer of dry grass and cover whole thing with the wet soil you removed. Let the water filter through the grass and drink it from the tube.

Tapping Trees in Early Spring (February until March) – Hardwood trees send up gallons of sugary sap in preparation for Spring. To tap the tree make a small hole with the tip of your knife and insert a wood spile to guide the watery sap. Collect the water into your cup or canteen. Once you’ve collected enough water seal the hole. Video

Water in Food – The juice and moisture found in foods can provide valuable water to your diet. Berries, roots, worms, and even blood in animals and fish can provide clean water to your survival effort. One survival technique suggests eating the eyes of fish as a water source.

Warnings
Watch for water on the lids of containers – While the water in the container the water around the lid may still be contaminated. Pour the water to another container before drinking.

Rinsing Food Off
– You may inadvertently contaminate your food by rinsing it in bad water. Washing off berries or food you dropped on the ground in a stream may subject you to micro organisms.

Contaminated Bottles Mixing With Clean Bottles – If a container has been used to transport unclean water is later filled with clean water it may contaminate the clean water. Make sure to completely dry out unclean containers in sunlight before using them as clean water containers.

Other Purification Methods
Household bleach – Use standard bleach without any scents or other cleaning agents. The bleach must contain chlorine to work. For bleach with 5% chlorine content use 8 drops of bleach per gallon or 2 drops per liter of water. Adjust the dosage based of the percent of chlorine content. Once you’ve added the bleach shake or stir well and let stand for 30 minutes. If the water is dirty or cold double the dosage and the wait time. Some words of warning with bleach, it kills some but not all contaminates and it degrades over time.

Calcium Hypochlorite – This chemical, sometimes called pool shock, can be purchased at any swimming pool store and is superior to bleach. When chlorine is in liquid form it degrades and becomes useless within a few years (and quicker if it is stored in the heat). The advantage of calcium hypochlorite is that it is in powder form and stores indefinitely. It kills all kinds of micro organisms in the water while bleach kills most but not all organisms. This chemical is extremely concentrated and will need to be diluted twice. The first step is to make the concentrated chlorine solution. Mix 5 milliliters (or 1 teaspoon) of Calcium Hypochlorite (78% grade powder) to 7.5 Liters (or 2 gallons) of water. Do not drink this concentrated mix. It is still very concentrated and could kill you. It starts to deteriorate once it’s in liquid form so don’t mix up more than you can use in 6 months. Add 1 part solution for every 100 parts water. For a smaller batch mix 2 teaspoons concentrated liquid for every 1 quart (or liter) of water. Allow this mixture to sit for 30 minutes if the water is clear (If the water is not clear or murky allow it to sit for an hour). For larger batches add 1 cup of concentrate to every 6.25 gallons of water. Notes on finding 1/100 ratio starting from drips. 24 drips = 1/4 tsp. 96 drips = 1 tsp. 203 teaspoons per liter. 192 teaspoons in a quart. 2 tsp (or 10 ml) to every 1 liter of water fulfills the 1/100 ratio.

Potassium Permanganate – This chemical can be found in some first aid kits. It kills micro-organisms through oxidizing the water. Adding this chemical will make the water slightly pink. This is an extremely dangerous option as too much of this chemical in the water could be lethal. Exercise extreme caution when using potassium permanganate.


Additional Resources:
https://howtoto.com/pdf/EPA_emergency-drinking-water.pdf