In 1988, the Boston (Mass.) Water and Sewer Commission began investigating the possibility of downsizing meters as a way of reducing unaccounted-for water. The authors of this article demonstrate that downsizing was successful for a variety of the commission's accounts. As of May 17, 1991, the commission had recovered more than 429,905 gpd of water by downsizing more than 400 meters of size 1.5 in. and larger. In addition to reducing unaccounted-for water, the downsizing effort could generate more than $2 million annually. Includes 6 references, tables, figures.