Jesse doesnt like drinking water either. He's bottle fed. He starts gulping it down then when he realises its water he spits it out. If ive noticed he's ever constipated ive just put an extra 5 or 10 mls water in the formula. Dont water it down too much though as it can upset their tummies. Our house is airconed so even on hot days he doesnt get dehidrated so im not too worried he doesnt drink it. But one other thing i know he'll drink the water out of is face washers. He'd drink his baths dry if id let him. So another thing ive done it give him a cooled wet washer (i soke it in coolded boiled water and put it in the fridge) .. is great for his teething and he then drinks the water too.