Build A Supply Of Water That You Will Need In An Emergency Water is an essential element to survival and a necessary item in your emergency preparedness so you must build a supply of clean drinking water. Following a disaster, clean drinking water may not be available. Your regular water source could be cut-off or compromised through contamination. Prepare yourself by building a supply of water that will meet your family’s needs during an emergency. You should store at least one gallon of water per person for three days. A normally active person needs about three quarters of a gallon of fluid daily, from water and other beverages. However, individual needs vary, depending on age, health, physical condition, activity, diet and climate. How Much Water Do You Need? To determine your water needs, take the following into account: One gallon of water per person per day, for drinking and sanitation….