As the aircraft was climbing through about 400 to 500 ft AGL, after takeoff, the engine began losing power. The pilot turned on the fuel boost pump and started a turn back toward the airport. When he realized that he could not reach the runway, he elected to land on a street. During the approach, the aircraft collided with telephone lines, then crash landed in the street. Before coming to rest, the left wing of the aircraft struck a vehicle. During an investigation, approximately 1 pint of water and other contaminants were drained from the left wing fuel tank. The right wing tank contained minor foreign contaminants. The fuel selector was found positioned to the right main wing tank and its screen contained extensive foreign contaminants. The engine driven fuel pump inlet line, carburetor inlet line, and carburetor filter screen contained water and other foreign contaminants. There was evidence that corrosion particles had collected in excess of a year and that the fuel strainer and valve had not been inspected for over a year.