This study was designed to evaluate the effects on evaporation of distilled water and tap water subjected to magnetic treatment for different periods of time. Evaporation of NaCl solu- tions magnetically treated was also studied. The magnetic trea- tment took place by circulation through a pipe with 125-mT ma- gnets. The evaporation of distilled water, tap water and 0.026 M NaCl solution that had been magnetically treated for 60 min, were 5.07, 4.53 and 3.60 % less than their respective control. The dyna- mic magnetization of water and solutions generates a decrease in the evaporation whereby this method could provide a mechanism to economize water, principally applicable to agriculture.