If you use any kind of aversion tactics like the shock tactic using the water, it is imperative that the dog doesn't think it is coming from you and that it is something that just happens when they engage in the unwanted behaviour.

That is why he still bites when you don't have the water bottle, because he realises the water comes from you.

You have to make something happen that the dog is unable to connect to you so that he believes it would still happen independantly of you.

Still, as the first poster said, at 5 months, he is still a pup and is likely to grow out of this as he gets a bit older but as the second person says, the fact that you overreact everytime will fuel his behaviour. You need to stop reacting because that is his current reward.