Do we drink enough?

I've read a few articles this morning some  saying tea isn't the same as drinking water, others say like the NHS that its 6 to 8 glasses of fluid a day. 

copied from  NHS - Water, lower-fat milk and sugar-free drinks, including tea and coffee, all count as part of your daily intake.

I just think you drink what seems right for you.

Here we go, I would change that to full fat milk if anything? We are the only animal that doesn't drink only water? If I wanted/had  to I could survive on meat, fat, salt and water! I don't, but I am trying to up my water intake!