Genesis 7:10-12

And after the seven days [God released the rain and] the floodwaters came on the earth. In the six hundredth year of Noah’s life, on the seventeenth day of the second month, on that same day all the fountains of the great deep [subterranean waters] burst open, and the windows and floodgates of the heavens were opened. It rained on the earth for forty days and forty nights.