A secure water supply is a necessity for active explorers and developers of hydrocarbons in the WCSB. This study evaluates water sources in deep aquifers (Viking and below) in three areas of east-central Alberta and in the Regina, Saskatchewan area. Zones evaluated range from the Lower Cretaceous Viking Formation to the Cambrian Deadwood Formation and include a number of Cretaceous sands and Mississippian and Devonian carbonates. Data used for the evaluations were DST recoveries and water disposal well and source well performance.