Most engineers probably feel that they are safely code compliant with their waterside economizers if their system is configured per Steve Taylor's June column: as an integrated economizer with the heat exchanger in series with, and upstream of, the chillers, if their cooling tower is intelligently selected for their peak load condition, and if they provide the appropriate controls to initiate economizer mode during the appropriate exterior conditions. But, they would likely be wrong. It's not only about the cooling tower.