Genesis says the floodwaters prevailed on the earth for 150 days.
Genesis 7:24 states that the waters prevailed on the earth for 150 days. This figure belongs to the broader Flood chronology and is different from the 40 days and 40 nights during which Genesis says rain fell. The rain duration describes one phase; the 150-day figure describes the period in which the waters remained dominant.
Genesis 8 then describes the waters gradually decreasing. The Ark came to rest on the mountains of Ararat, and Noah waited while the landscape became dry enough for departure. The narrative includes several waiting periods, including the intervals between sending the raven and dove, so the full story lasts longer than either 40 or 150 days alone.
Translations and readings of the chronology can lead to different modern summaries of the total time aboard the Ark. The answer to this question remains specific because it asks about the stated period during which the waters prevailed, not the complete duration from Noah’s entry until his exit.