On March 24, 1999, at about 1100 eastern standard time, a Fairchild Hiller FH-1100, N4412C, registered to a private owner, operating as a 14 CFR Part 91 repositioning flight, rolled over on its right side while attempting to pick up to a hover. Visual meteorological procedures prevailed and no flight plan was filed. The helicopter sustained substantial damage. The student pilot reported no injury. The flight was originating from his back yard at the time of the accident. The student pilot stated he was going to wash the helicopter in his back yard. He realized the garden hose was about 6 feet short of the right side of the helicopter. He decided to move the helicopter to the right about 10 to 15 feet. He started the helicopter and did a flight control check which was uneventful. He increased collective, cyclic, applied left antitorque pedal, and started to pick up the helicopter. Before he knew it, the helicopter rolled over on its right side. Examination of the engine and flight control assembly revealed no evidence of a precrash mechanical failure or malfunction.