According to Genesis, the Flood waters prevailed on Earth for 150 days before they began to recede.
Genesis 7:24 states that the waters prevailed for 150 days. Genesis 8:3 then says that God caused a wind to pass over the earth and that the waters subsided, marking a transition from rising or maintained flood levels to recession.
This figure is distinct from the 40 days and 40 nights of rain. The biblical account uses multiple time markers: rain lasts 40 days, the waters prevail for 150 days, and the narrative later records the ark resting, the appearance of mountain tops, and the eventual drying of the ground.
Readers sometimes combine these periods into one simple timeline. Genesis instead presents a staged chronology, and different traditional calculations can vary when they harmonize the dates. The 150-day statement itself is the direct figure given in the text.