According to Genesis, the floodwaters prevailed over the earth for 150 days.
Genesis 7:24 gives this figure after describing the rising waters that covered the mountains and destroyed life outside Noah’s Ark. The same narrative later says that God caused a wind to pass over the earth, after which the waters began to recede.
The 150-day period is not the same as the 40 days and 40 nights of rain. Genesis mentions 40 days for the rainfall, while its larger chronology describes a longer period during which the waters remained dominant. This distinction is a frequent source of confusion when the story is summarized.
Genesis also gives a detailed sequence involving Noah’s age, the Ark’s resting, and the drying of the ground. Readers comparing translations may notice small differences in wording, but the 150-day figure is a stable part of the standard English rendering of the narrative.