Even though I've now swapped over to Cambridge I still drink at least 4 litres a day - sometimes more. I find it dead easy now and manage it without even thinking about it. I use a 1 litre Volvic bottle (I have a collection of them!) and find they're really not very cumbersome to carry round- they fit in my handbag and thats no mean feat considering my bag contains no less than 7 kinds of lip gloss, hairbrushes, perfume, umbrella, gloves, purse, iPod, phone, keys and various other random paraphenalia lol!
On LL you just need to make sure you drink a litre with each pack. I drink a litre before/on the way to work, 1 litre before lunchtime, one in the afternoon and then 1 at home in the evening.
I also rarely drink water without flavouring (in fact the only time I drink plain water is in a pub as I think getting out a tub of white powder is slightly dubious!) and most of the time I drink the water hot (not boiling - just out of the hot tap) which I find makes it much easier to drink , kinda warms you up (anything is worth a try - for the last 2 nights I've had 3 hotwater bottles in my bed!) and apparently is good for your bowels ;o)
If you think drinking hot water sounds vile - I'd recommend you just try it with some FotF flavouring and you might be swayed
MM x