It's not spread by the government
but it is untrue. The actual recommendation was that you were supposed to take in (say) 8 glasses of water a day IN TOTAL - including such things as the water in tea, coffee, soup etc - not have all those things and then drink lots of water on top of that.
(apeloverage committed the vile act of onanism on, Thu 27 Aug 2009, 15:20, 2 replies)

Un-tea?
On Tetley boxes it warns that tea only counts toward your fluid intake if you drink 1 cup at a time, spaced throughout the day.

I always find myself wondering how tea stops becoming fluid if you drink two cups...
(Potedeian, Thu 27 Aug 2009, 16:15, closed)

If you drank all of your fluids all at once
you'd piss most of it out and then gradually get dehydrated throughout the rest of the day.
(Seance Trumpet has got no beef with a man enjoying a croissant, Sun 30 Aug 2009, 0:38, closed)

I remember reading
not so long ago. That someone had gone looking for the original research for how much water we need to drink, and couldn't find /anything/ ie no studies showing that you should drink any particular amount of any particular fluid to remain hydrated.
However, absence of evidence is not evidence of absence; so you'd probably better keep drinking something each day.
( Sextant goes to him is emotionally erect, on this day, Fri 28 Aug 2009, 16:48, closed)