Is he kept inside? I have noticed sometimes guinea pigs drink more if your heating is turned up and it's warmer in the house - a bit like how they drink more when it's warm in the summer.
Is he eating a full and varied diet, no problems?
my piggies are inside i thought it might be because the heating is on! i gave them some peppers tonight and max loves it but morris isnt intrested he sniffed it and walked off think i will have to keep my eye on him tommorow and buy him some cucumber which is his favourite and see if he eats it although earlier i did see him eating some dry food so hopefully he is ok!
my other piggy max drinks very little so it may just be some piggies drink more than others! i will keep my eye on him as he has been abit quiet today and not quite as happy as normal see how he goes tommorow!
One of ours drinks far more than any of the others, and also wee's far more! All mine are drinking more than usual at the mo, bit weird, perhaps it is the heating. I think mine are a bit like sheep, they go through phases, they'll eat carrot, then one will decide that's off the menu, bored of that, and they all stop eating it! They probably chat amongst themselves and do things like this just to wind us up!