Mike (my foster dad at the time) had decided to relax one eve and have a drink when he noticed it was looking a lot lighter colored than it should as he was pouring it and commented on it. (It was probably nearly 50% water at that point, as were several other bottles.)
Of course we denied any knowledge of what could have possibly happened but he pretty much figured it out on the first sip. After his screaming rant he ended up grounding us for I think a month(?) (I was in grade 7, this was a long time ago.) not that it mattered to me… I was a bit of a dick back then and just wouldn’t come home after school anyway. I lived there for a couple more months before my foster mom had a nervous breakdown (not entirely related to that particular incident) and I was shipped to a different home outside the city.