In Genesis 7, seven days passed before the Flood waters came after Noah entered the Ark.
Genesis 7:10 says that after Noah, his family, and the animals entered the ark, the floodwaters came upon the earth after seven days. This waiting period is distinct from the 40 days and 40 nights during which rain fell. Genesis also gives a separate figure of 150 days for the period when the waters prevailed.
The seven-day interval appears twice in the immediate chronology. Genesis 7:4 records God announcing that the rain would begin in seven days, and Genesis 7:10 reports the fulfillment of that interval. This repetition helps structure the narrative and marks the transition from preparation to judgment.
The number is easy to confuse with other Flood figures because the story contains several precise durations. Seven days describes the delay before the waters arrive; 40 days describes the rain; 150 days describes the prevailing waters. Keeping those time markers separate produces the canonical answer.