Apparatus for cleaning a surface with a liquid jet, the apparatus having: a primary fluid conduit having a longitudinal axis and two ends, a fluid-intake end and a fluid-exit end; a first motor-driven drive assembly configured to engage the primary fluid conduit and turn the primary fluid conduit about the primary-fluid-conduit longitudinal axis; a first motor configured to engage the first motor-driven drive assembly; a section of the primary fluid conduit being inside of an adjacent penetration sleeve; a section of the penetration sleeve being inside of a piston sleeve; the piston sleeve configured to engage the penetration sleeve and move the penetration sleeve back and forth along a penetration-sleeve linear path over a primary-fluid-conduit exterior surface; an actuator configured to engage the piston sleeve and move piston sleeve back and forth along the piston-sleeve linear path; a penetration-sleeve end being attached to an extension sleeve that has a first end and a second end; the extension-sleeve second end being attached to a swivel rod that has a first end and a second end; the primary-fluid-conduit fluid-exit end being attached to a fixed nozzle having a first end and a second end; the fixed-nozzle second end being attached to a swivel nozzle; the swivel-rod second end being attached to the swivel nozzle; the swivel nozzle configured to pivot between a fully extended position and a fully retracted position as the swivel rod respectively extends and retracts as the penetration sleeve moves back and forth; the swivel nozzle being attached to a nozzle pipe; the nozzle pipe being attached to a nozzle configuration that is configured to open and close a flapper door having a fluid exit orifice; and a continuous fluid-flow channel that extends from the primary-fluid-conduit fluid-intake end through the swivel nozzle.