The pilot reported that while maneuvering about 900 ft above ground level (agl), he reduced the engine throttle to 1,000 RPMs to begin a descent to 500 ft agl to overfly a lake. Shortly thereafter, the engine “sputtered”, and he began to troubleshoot the engine problem “all while looking for a place to land.” He then realized the engine issue could be carburetor ice. He reached for the carburetor heat handle, and the airplane impacted a power line. The airplane impacted the water and sustained substantial damage to the left wings and fuselage. The passenger reported that the airplane was “running completely fine the entire ride, we then began flying really low [and the pilot] said, ‘this is where I like to do some water dancing.’” The pilot continued to fly low over the water around the curves of the lake, and the engine continued to operate without an issue. While flying level, the passenger noticed the airplane was about the altitude of some power lines when the airplane impacted the power lines and then the water. A nearby boat assisted with their egress from the water. Automatic Dependent Surveillance-Broadcast data was consistent with the passenger’s recollection of the flight path and circumstances.