The report examines the relationships between agricultural policies in the North China Plain, the approaches to water management that evolved from them, the quantity of water that was actually used, and the consequent groundwater depletion beneath Luancheng County, Hebei Province, from 1949 to 2000. To systematically address these relationships, we use a comprehensive water-balance approach. Our results indicate that a single, longstanding policy-that of using groundwater to meet the crop-water requirements not supplied by precipitation-is responsible for the steady rate of groundwater decline.