The pilot/owner stated she had recently purchased the airplane and that during the preflight inspection, had found water in the fuel tanks. She then drained fuel from the sumps until no water was observed. Engine start, taxi, run up, and one circuit of the traffic pattern were uneventful. After completing a touch-and-go landing, during initial climb, the engine experienced a total loss of power. The pilot elected to land straight ahead and transferred control of the airplane to the pilot in the right seat. When he cycled the throttle from idle to full the engine sputtered before losing power again. The airplane subsequently struck a fence, nosed over, and came to rest inverted resulting in substantial damage to the airplane’s fuselage and both wings. Postaccident examination of the airplane found water in the fuel lines from the right wing fuel tank, in the strainer, and in the carburetor bowl. The fuel filler caps, and filler necks were corroded and the mechanic who had last performed maintenance on the airplane reported that he had removed water from the airplane’s fuel system and had changed the gaskets on the fuel tank caps one month prior to the accident. No maintenance log entries documenting this work were found in the supplied maintenance logbooks; the last entry was for the annual inspection completed about 9 months before the accident. Fueling records showed the airplane had last been fueled about 5 months before the accident. The examination otherwise found no evidence of any preaccident mechanical malfunctions or failures that would have precluded normal operation of the airframe or engine. Based on this information, the loss of engine power was likely the result of water contamination of the airplane’s fuel system that had not been detected or addressed by the mechanic.