Noah waited seven days before sending the dove again after its first return. Genesis 8:10 says Noah waited another seven days and then sent the dove from the Ark a second time.
The first release of the dove produced no resting place, so it returned to Noah. After the seven-day interval, the dove came back with a freshly plucked olive leaf, showing that the waters had receded enough for vegetation to appear.
Noah waited another seven days before releasing the dove a third time. It did not return, and Noah inferred that the land was becoming dry. The repeated seven-day intervals create a measured rhythm within the account's description of the waters retreating.
This detail is often missed because popular summaries focus on the olive leaf rather than the timing of the releases. The text gives a specific interval both before the second release and before the third.