On June 7, 1999, at 1830 central daylight time, a Robinson R-22, N9071T, was substantially damaged after takeoff. The 14 CFR Part 137 sprayer equipped helicopter was departing a field five miles south of Salem, Missouri, en route to a nearby field where the helicopter was going to be loaded with chemicals for aerial spraying. The helicopter climbed approximately 100 feet at 50 knots when it experienced a yaw. The commercial pilot executed an autorotation. The helicopter impacted the ground hard. The pilot received serious injuries. Visual meteorological conditions prevailed and no flight plan was filed. The pilot reported that he had conducted a preflight of the helicopter that included draining the sumps to check for fuel contamination. He reported he hovered the helicopter to a location where he had the helicopter "hot fueled" out of a service tank that was in the flatbed of a pickup. The pilot remained at the controls while the hot refueling occurred. The pilot did not check for fuel contamination after the helicopter was hot refueled with 8 to 10 gallons of fuel. The pilot reported that he conducted a 12 minute ground run. He reported taking off to relocate the helicopter to the field where agricultural spraying operations were to be conducted. He reported that he flew about 1/2 mile and was about 100 feet above ground level traveling at about 50 knots when the helicopter yawed to the left and the low RPM light illuminated. He reported the engine quit and he entered an autorotation. He reported that he needed to pull some collective to avoid a tree. He reported that he completed the autorotation, but the helicopter was in a high rate of descent with very little blade inertia when he impacted the ground. An inspection of the helicopter revealed that the fuel sump, carburetor, and adjacent fuel lines were contaminated with water. A fuel sample was taken from the bottom of the fuel service tank located on the back of the pickup and it also was contaminated with water.