According to the pilot, he made a pass over the lake in search of a landing site with the least amount of boat traffic. After an uneventful water landing, he began to water taxi the airplane; however, his passenger and he noticed a large wave approaching at a 45 degree angle from the port side of the airplane. As the wave impacted the airplane’s pontoons, the pilot encountered a strong left rudder deflection and the airplane nosed over into the water. A postaccident examination by a Federal Aviation Administration inspector revealed substantial damage to the airplane’s nose section. The pilot reported no preaccident mechanical malfunctions or failures of the airplane that would have precluded normal operation.