Wa alaykum salaam
According to your question when your wife woke you up ,she told you the azan is said. Despite of that you drank water. Ands if you were confused it was your duty to get assurance before drinking or eating anything.
For those who intentionally eat or drink after subh azan,their fast is batil. They have to pay the qadha of the fast and pay kaffara as well.
The kaffafa is :
Ruling 1630. The kaffārah for breaking a fast (ifṭār) unlawfully in the month of Ramadan is that the person must free a slave, or fast for two months in accordance with the instructions that will be mentioned in the next ruling, or feed sixty poor people (fuqarāʾ) or give each one of them a mudd – which is approximately 750 grams – of food, i.e. wheat, barley, bread, or suchlike. In the event that none of these are possible for the person, he must give charity to the extent that he can. If this is not possible either, he must seek forgiveness from Allah; and the obligatory precaution is that he must give kaffārah whenever he is able to.