Harvey,
I think the recommended fluid intake is around 6-8 glasses a day, based on a 250ml glass. I would say that 8 glasses would be the better option. A pint is approx 550ml, so 3-4 pints would be 1650-2200ml, which at the higher figure would be than the 8 glasses per day. We also obtain water from other food sources such as vegtables. I read that it doesn't matter how you get your recommended amount of fluid, so tea and coffee would be fine, but I would still include some water in this figure.
Of course certain foods have a high salt content, I know when I have eaten late and had salty food, say chinese/Indian food for example, I wake in the early hours with a dry mouth, think everybody does!
As you are not on any medication for bp or water retention, I would again suggest to you to see your gp and explain to him the nature of your problem. As you'll appreciate, I am in no position to say what may be causing your problem, I can only offer advice based on my limited knowledge and experience.
Good luck!
Nigel