Compliant leak detection system. The system includes structure adapted to support at least two rows of leak detection leaves, each leak detection leaf supported by an arm pivotally attached to the structure and urged outwardly by a torsion spring into contact with a pipe wall so as to adjust for changes in pipe diameter. The leak detection leaf includes a rigid support and a flexible member such that suction from a leak will cause the flexible member to contact the pipe wall and put a drag force on the structure. An axial force transmitting drum measures the drag force to indicate presence of a leak.