What is water under the bridge?

"Water under the bridge" is an idiomatic expression used to describe past events or situations that are no longer considered significant or worth worrying about. The phrase often implies that whatever happened is now behind us and should be let go, similar to how water flows under a bridge and keeps moving forward. It is commonly used to suggest forgiveness or to indicate that a particular issue or conflict has been resolved and is not worth revisiting. The metaphor emphasizes the passage of time and the idea of moving on from past grievances or mistakes.