Answer:
Water intake depends on several factors including age, gender, level of activity, and lifestyle. Doctors have long recommended 8 cups a day as a general rule of thumb, but this does not necessarily hold true for everyone. But if we were to make this rule true for simplicity's sake, then a 5-person family would consume about 2 1/2 gallons per day, because there are about 16 cups in a gallon. But in a whole week we use over 200 gallons of water.