If your passport has been significantly damaged, you will need to apply for a new passport. Damage on the book cover or the page displaying your personal data and photo is considered significant damage. Additional damage to your passport includes water damage, a significant tear, unofficial markings on the data page, missing visa pages (torn out), a hole punch, or other injuries.
Normal “wear and tear” of a U.S. passport is expected and likely does not count as “damage.” Normal wear includes the bend of a passport after being carried in your back pocket or fanning of the visa pages after extensive opening and closing.
If you need to replace your damaged passport, you will need to submit the following in person: