According to Genesis, the Flood waters prevailed around Noah’s Ark for 150 days.
Genesis 7:24 states that the waters prevailed upon the earth for 150 days after the Flood rose. This is a different measurement from the 40 days and 40 nights of rain. The text first describes the waters rising and covering the mountains, then later describes their gradual recession.
The 150-day period helps explain why the ark story is not presented as a brief storm. Genesis 8:3 says the waters began to abate after that period, marking a transition from the Flood’s maximum phase toward the ark’s eventual resting place.
Readers sometimes combine the story’s time spans into one figure, but the narrative includes several separate intervals. The rain, the prevailing waters, the recession, and Noah’s eventual departure from the ark are not interchangeable events. The answer here specifically identifies the period during which the waters prevailed.