> 8 gallons per person per day. Water is heavy—8 pounds per gallon
The average person needs far less than 65lbs (30kg) of water per day, which is a third of the average male weight in the US.
By medical standards humans need more like 8lbs (under 4l) per day for men and 6lbs (under 3l) for women. Less if your rationing and not exerting yourself.
The normal amount in disaster preparedness is 1gal per person per day. The problem with the larger amounts is that people see they need huge amounts and don't do anything. Better to get started storing 5-7 gal for each person.
The way to allow for extras is to store water for a longer length of time. If recommended value is two weeks, and it is in my area, then a month is a good buffer.
The average person needs far less than 65lbs (30kg) of water per day, which is a third of the average male weight in the US.
By medical standards humans need more like 8lbs (under 4l) per day for men and 6lbs (under 3l) for women. Less if your rationing and not exerting yourself.