Noah waited seven days after entering the Ark before the Flood began.
Genesis 7:10 says that after the family and animals entered, the floodwaters came upon the earth seven days later. This interval is separate from the 40 days and 40 nights during which rain fell.
The short waiting period provides a transition between the Ark’s loading and the arrival of the disaster. Genesis presents the animals entering in accordance with the instructions given to Noah, followed by the closing of the Ark and the beginning of the waters.
Readers sometimes merge the seven-day wait with the rainfall duration, producing an incorrect total of 40 days from entry to the Flood. The narrative actually identifies both numbers separately: seven days before the waters came, and 40 days of rain.