In A Quiet Place, Evelyn hides in a soundproof basement with her new-born. Eventually, the place is flooded with water.
Where did the water come from, and why? I just assumed it was a broken pipe or something, but maybe I've missed something.
A pipe is broken by the monsters while Lee and Evelyn are hiding. After Lee sneaks back out to go find the children, it is shown that the entire area upstairs has been trashed by the monsters. As he leaves the building the camera pans onto the floor where we can see water spreading, and the panning continues to show a broken pipe.