Life is very rewarding when you have a puppy, but without proper training it wont outgrow any bad behaviors it might have, and an example of that is biting. I tell people who ask me that this is just a puppys natural instinct, and will outgrow it at some point.
Only when the puppys biting really gets out of hand should you think about steps how to get it to stop biting.
You can use water as a simple obedience training to get your puppy to stop...