It’s always No. 2 for Clay Aiken.

The “American Idol” runner-up is facing a $60,000 lawsuit by a neighbor at his luxury Harlem condo building — who says his clogged toilet leaked into her unit.

Elizabeth Rothstein, a lawyer who lives below Aiken at 111 W. 110th St., says the foul flood occurred Jan. 21.

Aiken, who came in second on the TV show in 2003, “clogged the toilet with improper foreign materials,” Rothstein, 39 sniffs in court papers.

She claims the 38-year-old singer “improperly and negligently operated and maintained the toilet in the Aiken unit.”

The leak caused “extensive damage to Rothstein’s apartment and belongings,” her suit says. She’s suing over the property damage, repair costs and cleaning services.

Reps for Aiken did not immediately return messages seeking comment.