This study investigated the use of low temperature geothermal resources to convert salty produced water into a freshwater resource. The research retrofits soon-to-be-shut-down oil and gas wells as geothermal wells, simultaneously overcoming drilling costs and scale formation by using a freshwater closed loop system for thermal energy delivery. Heat transfer modeling was combined with water treatment thermodynamics to develop a predictive tool that can be used to estimate daily deliverable treated water. Results indicated that the developed model was most sensitive to well depth, geothermal gradient, and total dissolved solids in the produced water. Results also indicated that a 4000 m deep well with a geothermal gradient of 0.05 degrees C/m can successfully treat produced water with as high as 170,000 mg/L total dissolved solids and still deliver almost 600,000 L of clean water per day. An illustrative demonstration indicated that in the Eagle Ford Shale in Texas, > 60% of the drilled basin area can deliver at least half a million liters of treated water daily under ideal conditions. This is particularly meaningful as Texas experiences extended periods of drought and the treated produced water would represent a new and resilient source of water. (C) 2017 Elsevier B.V. All rights reserved.