Stainless Steel 316 and its reaction with Ag ions were investigated because of the use it has in potable water systems on spacecrafts. The objective of this study is to stop the depletion of Ag by precoating the SS316 coupons with Ag, AgNPs, and sulfidized silver. The coupons were exposed to AgF at 400 ppb solution and agitated for three days, the biocidal silver form used in the ISS, at a surface volume ratio of 2/cm. The Ag depletion from the solution was measured by Inductively Coupled Plasma Mass Spectrometry. The results of this study identified the type of surface coatings that maintains the biocidal activity of silver in the water storage system of the International Space Station.