17 States are within Reclamation and most are in the west; including legal marijuana states Colorado and Washington. All these 17 states are within the Controlled Substance Act and therefore aren't allowed for marijuana growing. There is about 1.2 acres of irrigated land that is from Reclamation used for Colorado and Washington. The bureau controls many dams and waterways that run through the west. Currently, many growers are using Reclamation water and are just shutting their mouths.
Over time, we'll see what happens with federal water in regards to marijuana. One thing we now, the plant needs it to survive.