Because water is a basic need you simply cannot live without, maintaining a safe water supply is essential. It is one of the most important elements for being self sufficient. Most healthy adults can survive about three to four weeks without food. However, you can only last 3 to 4 days without water.
Besides, in order to be properly prepared for an emergency situation, you must always have access to a safe water supply. For example, during a major flood event, well water, rivers, streams, lakes and ponds can become contaminated. That contamination can be in the form of chemicals, human sewage, livestock waste, as well as many other potential toxins. Consequently, best practice dictates being completely independent of any sort of infrastructure.
Furthermore, even if you are connected to the public infrastructure, this is no guarantee of a safe water supply. The reason is that during a natural disaster it is common for the public infrastructure to be...