Our Toto [female] always drinks lots of water .... and she has done this ever since we brought her home at 16 weeks. She has been checked insideout several different times and sees her vet every couple of months. [OK ... we're a tad over-protective!
] Our vet says that some just love the taste of water and she's one of them. We take a bottle of water even if we are just going for a short walk. It would be wise to have your baby checked out but it may be that he likes the taste of water.