Newborn drinking water?

I Always thought that giving a newborn water was bad? When I read up on it also it says that it's bad as it bloats their tummies and stops them eating? However my MIL said that it's fine to feed a baby a little bit of water,(half an ounce) because they get dehydrated and thirsty too?! She said it could be why my baby wakes up at night (after being fed and he's not Hungry). what have you been told in regards to this?