According to Genesis, how long did the floodwaters prevail around Noah's Ark?

According to Genesis, the floodwaters prevailed for 150 days around Noah’s Ark. Genesis 7:24 states that the waters prevailed upon the earth for this period.

The figure is not the same as the forty days and nights of rain. Genesis describes the rain as lasting forty days, then separately reports that the waters remained dominant for 150 days. The distinction helps explain why the flood account continues long after the rainfall stops and why the ark does not immediately come to rest on dry ground.

The narrative later says that the waters began to decrease and that the ark came to rest on the mountains of Ararat. It then records further waiting before the mountain tops, the ground, and finally the land were dry. Different passages in Genesis provide dates and intervals for these stages, and readers sometimes merge them into one duration. The safest answer to this specific question is the exact period attached to the phrase “waters prevailed”: 150 days.