It’s never a good sign when a singer has had more tax liens than platinum albums — but that’s the situation former “American Idol” champ Ruben Studdard has found himself in … TMZ has learned. 

According to docs filed in Alabama, Studdard and his estranged wife Zuri owe $180,216.73 in federal taxes for the year 2009. 

Studdard is no stranger to tax problems in Alabama — he had a property lien filed against him back in 2008 to the tune of nearly $200,000.