Unclean water often contains pathogenic substances, so when you find a water source while extremely thirsty, it’s best not to drink it immediately. Instead, purify and disinfect the water according to the environmental conditions to avoid poisoning or disease.
Here are some simple and feasible methods for purifying and disinfecting the water you find.
### 1. Percolation Method
If the water source contains floating debris or is murky, dig a pit about 50-80 cm deep and 1 meter in diameter, 3-5 meters away from the water source. Allow the water to naturally percolate through the sand, stones, and soil. Gently collect the percolated water into a container like a box or kettle.
Note: Avoid stirring up the mud at the bottom of the pit to keep the water clean.
### 2. Filtration Method
When the water source is muddy, with floating debris, microorganisms, worms, or leech larvae, and the surrounding environment is unsuitable for digging a pit, you can use a plastic bag (of good quality, not easily torn). Puncture small holes in the bottom, or use a cotton glove, handkerchief, sock, sleeve, pant leg, or even a soda bottle with the bottom removed and inverted. Use a knife to poke a few holes in the cap, then layer 2-4 cm of clean, soil-free fine sand, charcoal powder, fine sand, charcoal powder, and fine sand, pressing each layer firmly. Slowly pour the dirty water into the improvised filter. When water starts dripping from the bottom, collect the filtered water in a basin or kettle. If the water quality is still unsatisfactory, repeat the filtering process with another improvised filter until satisfied.
### 3. Sedimentation Method
Collect the water in a basin or kettle and add a small amount of alum, crushed kapok leaves, crushed cactus, or crushed elm bark. Stir well and let it settle for 30 minutes. Gently scoop the clear water from the top, avoiding the stirred sediment. This will give you relatively clean water.
In general, except for spring water and deep well water, all water—whether from rivers, lakes, streams, snow, rain, dew, or filtered and sedimented water—should be disinfected before drinking. Here are some methods for disinfection:
1. **Purification Tablets**: Add purification tablets to the container, stir, and let it sit for a few minutes before drinking. Store the purified water in a kettle. Usually, one tablet can disinfect one liter of water. If the water is very turbid, use two tablets. This method is commonly used by military personnel in the field.
2. **Iodine**: If you don’t have purification tablets, use medical iodine instead. Add 3-4 drops of iodine per liter of purified water. If the water is turbid, double the iodine. Stir and let it sit for 20-30 minutes before drinking.
3. **Bleach**: Sodium hypochlorite (bleach) can also be used for disinfection. Add 3-4 drops of bleach per liter of purified water, doubling if the water is turbid. Stir and let it sit for 30 minutes. The water might have a slight bleach taste, so avoid drinking the sediment.
4. **Vinegar**: In the absence of other disinfectants, you can use vinegar. Add some vinegar to the purified water, stir, and let it sit for 30 minutes before drinking. The water will have a slight vinegar taste.
5. **Boiling**: At altitudes below 2500 meters and with a fire source, boiling water for 5 minutes is an effective disinfection method. It’s simple and practical, especially for purifying river, lake, stream, rain, dew, and snow water during outdoor activities.
6. **Treating Saline Water**: If you find saline water, boiling it with certain plants like local herbs can help reduce bitterness and salinity. For water with heavy metals or toxic minerals, boiling it with strong tea can cause the toxins to precipitate out; avoid drinking the sediment.
Currently, there are water purification straws available that are very practical for outdoor use. They look like a thick pen and can purify water to be free of bacteria, toxins, and impurities, making it safe to drink without boiling.
Additionally, it’s crucial to manage your drinking water wisely in a shortage. Avoid drinking too much at once. Instead, drink small sips slowly to allow the body to fully absorb the water and keep your mouth and throat moist. This way, a standard water bottle can last a single person 6-8 hours, or even longer, during physical activity.
