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