For risk assessments, the average current residence time (time since moving into current residence) has often been used as a surrogate for the average total residence time (time between moving into and out of a residence). Since the distributions of the two quantities are not necessarily the same, neither are their averages. Housing surveys provide current residence time data; total residence times must, therefore, be inferred. By modeling the moving process, the total residence time distribution can be estimated from current residence time data. Using 1985 and 1987 U.S. housing survey data, distributions and averages for both current and total residence times were calculated for several housing categories. The average total residence time calculated for all U.S. households, 4.6 (se= 0.6) years, is less than half the average current residence time, 10.6 (se= 0.1) years.