On October 15, 2020, about 1615 Pacific daylight time, a Cessna 152, N6585L, was substantially damaged when it was involved in an accident near South Hill, Washington. The pilot sustained minor injuries. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. The pilot reported that he had purchased the airplane 8 days before the accident via an online auction. The airplane was parked outside and partially covered for several years before the purchase. The pilot said that he worked on the airplane to facilitate an engine run, which included draining the fuel from wing fuel tanks and the airframe fuel filter, during which he observed water in the fuel. The pilot continued to sump the fuel tanks and airframe fuel filter until no more water was present, and conducted multiple engine runs, with no issues noted. The day of the accident, he decided to relocate the airplane to Auburn, Washington. Following an uneventful engine run-up, he initiated takeoff on runway 35. As the airplane climbed through about 250 ft above ground level, the engine lost partial power. The pilot initiated a forced landing to a nearby parking lot, during which the airplane impacted an unoccupied parked vehicle, resulting in substantial damage to the fuselage and wings. Evidence of fuel was observed at the accident site. The airplane was recovered to a secure facility for further examination. The left-wing fuel tank was absent of fuel; however, a fuel line leak was identified consistent with impact damage. The right-wing tank contained about 1.5 gallons of fuel and water. Visual inspection of the tank revealed clear liquid droplets along the bottom of the tank, consistent with water. The bottom edges of the tank exhibited rust discoloration. Engine valve and drivetrain continuity was established when the crankshaft was rotated by hand. Cylinder No. 2 was impact damaged. The top spark plugs displayed wear; the No. 1 cylinder plug was severely worn. The No. 1 cylinder bottom plug exhibited lead deposits; the No. 2 bottom plug displayed foreign debris within the electrode area, and the No. 4 bottom plug was oil-soaked. The magnetos remained attached to the engine and produced spark at all terminal leads when the engine was rotated.