I am glad that scientists are finally coming out with this. There are so many variables concerning the, "right" amount of water to drink daily. It depends on how much a person sweats throughout each particular day, how much water is in the foods one eats each day, and how much the person weighs, for example.
I am 5 feet tall. I generally don't need 8 full glasses (8 OZ) of water per day. Yet, if I am working search and rescue in 100 degree heat for hours I might need 12 glasses of water per day.
A 6' 4" lumberjack working very hard at his trade for 10 hours in the heat of summer will need a lot more water than a 5' tall, light weight woman sitting at a desk in air conditioning all day.
So I never believed in the 8 glasses per day ideal, anyway. It simply isn't logical to think that all of us need 8 glasses of water per day no matter what our sizes are, the temperature at which we spend much of our time in, what foods we consume (i.e. gravy, pudding, and many other foods have lots of water that counts towards what we need), and our overall health. I drink anywhere from 5 to 12 glasses per day depending on what I ate (with water in it), and how much I sweat (training dogs, SAR in the heat).
Now I'll have that Vodka and OJ with ya jelly if ya like