The LING has two evaporators, built by E. G. Badger Company, that distilled sea water into fresh water. While a tremendous asset to submarines, their limited capacity (about 1,000 gallons/day each) required conservation of fresh water and limited bathing by the crew. The primary consumers of fresh water were the boat's batteries.
Battery water had to be distilled twice, reducing the output to 500 gallons/day. The evaporators and condensers had to be completely flushed and cleaned, then filled with water from the fresh water tanks. Distillate from this operation went into the battery water tanks, located in the battery wells. Since the batteries consumed approximately 1,800 gallons of water per week, if everything was running right and running full time, half the output capacity went to making battery water. The remainder was used for cooking, drinking and lastly bathing.
Components of the evaporators were the distilling unit, electric motor, compressor, heat exchanger, electric heating elements, and the pump and receiving tanks. Concentrated brine was discharged overboard.