Genesis says the Floodwaters prevailed over the earth for 150 days in Noah’s Ark story.
Genesis 7:24 states that the waters prevailed upon the earth for 150 days. This figure describes the period during which the waters remained dominant, not simply the time rain was falling. Genesis separately says rain fell for 40 days and 40 nights, a detail that is often mistakenly substituted for the total duration of the Flood.
The narrative then records a turning point: God causes a wind to pass over the earth, the waters subside, and the Ark comes to rest on the mountains of Ararat. The chronology continues through the drying of the ground and Noah’s eventual departure.
The numbers belong to the internal chronology of Genesis. Attempts to reconcile every date into a single scientific model involve interpretations beyond the wording of the text. For trivia, 150 days is the direct answer to how long the waters prevailed.