A supporting ring is clamped about a pile and a cleaning ring is supported below the clamping ring by a cable threaded through a number of pulleys, allowing the washing ring assembly to be raised or lowered along a pile. A washing ring carries a four high-pressure water jets that spray water against the pile while the washing ring oscillates through 110-120 degrees of arc, driven by a hydraulic motor through a gear ring. A stabilizing ring fits into a C-shaped channel formed by the washing ring, supporting the cable pulleys. Both the washing ring and the stabilizer ring can be broken down into two semi-circular sections, required for installation and removal in most applications, and are fastened together by a number of over-center clamps.