What I think she meant was...
water under the bridge (or water over the dam)
phrase of water
- 1.
used to refer to events or situations that are in the past and consequently no longer to be regarded as important or as a source of concern.
spoon·er·ism ˈspo͞onəˌrizəm/ noun a verbal error in which a speaker accidentally transposes the initial sounds or letters of two or more words, often to humorous effect, as in the sentence you have hissed the mystery lectures, accidentally spoken instead of the intended sentence you have missed the history lectures.