The commercial production of cranberries relies on abundant water resources for frost protection, soil moisture management, and harvest and winter flooding. Given water resource demands and regulations in southeastern Massachusetts, we sought to quantify the annual water requirement for the commercial production of cranberries. Based on 2 yr of monitoring across five sites, the mean water requirement for cranberries was 2.2 (±0.6) m yr^-1 (one standard deviation in parentheses). On average, the 3 mo maximum area threshold of 3.15 ha was within ∼20% of the value currently used to establish water permits for renovated cranberry farms in Massachusetts. Variation in the water requirement was primarily related to differences in the harvest and winter floods, which combined for two-thirds of the annual water requirement. The water requirement for the winter flood exhibited the greatest annual variation (54%), which was relatively low for the harvest flood (20%). Environmental variation was significantly related to water requirements for the winter flood, as well as seasonal irrigation, and should be carefully considered in agricultural water use regulations.