My cat wont drink tap water either. My dad gives bottled water (just a cheap bottle) to his cats and they drink that so maybe try that. Its something to do with the chemicals found in tap water I think that some cats dont like.

Regarding milk, some cats cant stomach it due to the lactose. I give my cat Whiskas Cat Milk as that is lactose free and she is fine on it. In fact she loves it :0)