Rumpf and Meurisch (1981) conclude that any magnetic field including particularly that of the earth, can deflect the line of sight of compensator or automatic (self leveling) levels. Since the City of Los Angeles has observed many lines of geodetic leveling using a Zeiss Ni-1 level, a field investigation was designed to assess the potential impact of this error source. The observations were made along a line that had been releveled several times over a period of years. This, generally, north-south line runs from Tidal 8, San Pedro, to the vicinity of the Jet Propulsion Laboratory in LaCanada (Figure 1). An additional line of leveling was also observed in an east-west direction. Our investigation seems to confirm the existence of an azimuth dependent error as suggested by Rumpf & Meurisch.