Having a water purification method is one of the most important parts of disaster prepping. It is also one of the most confusing. The reality is that there is no one “best” method of purifying water in disaster situations. A water treatment system designed for back-country use where viruses aren’t likely, probably won’t be safe for treating flood water in an urban environment.
Boiling is a good way to treat water in most types of common disaster situations, such as grid outages when the water treatment center stops working. Most sources say that you need to boil water for 1 minute to kill bacteria, viruses, parasites, etc. Pros: Kills most common threats, Easy to do. Cons: Requires time, heat, and fuel, Won’t remove chemical threats
2. Chemical Treatments.
The term “chemical” water treatments is a bit confusing, but these are actually one of the most common methods for treating contaminated water. For example, you can buy water treatment tablets or drops to put in unsafe water to kill bacteria, parasites, and viruses. Pros: Bleach is cheap and readily available, Kills most common threats, Portable. Cons: Doesn’t remove sediment from water, May create a bad taste, You have to let the water sit before using, Doesn’t remove chemical threats
3. Mechanical Filtering.
Water filters are considered a type of “mechanical” water treatment because they literally trap contaminants that go through them. There is a lot of variability in water filters, so you need to be really careful when choosing one. The most important thing to look at is micron size rating. Pros: Many options available, Portable, Cheap. Cons: Not all products remove viruses, You may need to buy replacement filters, Not all filters are made equal.
4. UV Treatment.
Ultraviolet light causes the DNA in bacteria, viruses, and parasites/protozoa to scramble. They will still be in the water, but they will be harmless. You can buy UV water treatment wands. To use them, you put the wand in the dirty water, push a button, and let the UV light do its work. Pros: Destroys common threats including viruses, Portable. Cons: Doesn’t remove sediment, Requires a battery, Pathogens can reactivate if you let the water sit for a long time, Doesn’t remove chemicals.
Most home water distillers work by boiling water and then collecting the steam. The steam is channeled into a separate container where the vapor cools and turns back into water. The idea behind distillation is that microorganisms and pollutants are left behind.
6. Reverse Osmosis.
Reverse osmosis systems are very complex and somewhat expensive. They work by hooking up to your water system and forcing pressurized water through a special membrane. When it comes to treating water, reverse osmosis is one of the most effective single methods you can use. Pros: Very effective at purifying water. Cons: Hooks up to plumbing system so won’t work when water system is down, Wastes a lot of water, Expensive, Not portable.