On February 23, 2021, at 1645 Pacific standard time, a Mooney M20E, N3254F, was substantially damaged when it was involved in an accident near Livermore, California. The pilot and one passenger were not injured. The airplane was operated as a Title 14 Code of Federal Regulations Part 91 personal flight. According to the pilot, the takeoff from runway 7 was normal; about 100 ft above ground level (agl), the engine lost total power. The pilot elected to make an off-airport landing about 1 mile northeast of the airport on the overpass of Interstate 580. During the landing roll, the propeller struck the trunk of a car. The airplane pivoted around and impacted the left side of the car before coming to a stop near the side of the road. The driver of the car, the sole occupant, was not injured. According to a Federal Aviation Administration (FAA) inspector, the airplane sat outside, and had not been flown for about 8 to 10 years before the accident flight. When the fuel tanks were slumped, a small quantity of water was present in the right fuel tank, and the left tank was free of contamination. A visual examination of the engine revealed no evidence of any mechanical damage to the crankcase. The engine was manually rotated, and mechanical and valve train continuity established. The engine-to-magneto timing was within manufacturer limits. The spark plugs were removed and were in good condition. When the engine was manually rotated, the P-leads sparked at all cylinders. The fuel flow divider was disassembled and was clear of debris; the diaphragm was intact. The fuel injectors were removed and were clear of debris. A visual examination of the fuel servo revealed that it was intact and not damaged. The throttle and mixture levers were free to move from stop-to-stop. Before attaching it to the test stand, the fuel servo inlet screen was removed and inspected; debris was observed in the inlet screen. A functional test of the fuel servo was unsuccessful; no fuel flowed through the unit. The fuel servo was disassembled for further examination. Extensive corrosion and debris were noted in the regulator center body and diaphragm assembly, which prevented a successful fuel flow check on the test stand. The corrosion and debris were attributed to water in the system.