DM Plants are used for effective removal of mineral salt present in water. Demineralization plants adopt ion exchanging method for effective distillation of water. These types of plants comprise of MS or FRP rubber lined pressure vessels that have several internal fitting accessories. Strong acidic cation exchanging resin of these DM Plants plays significant role in converting positive ions of salt into hydrogen ions. Produced acid generated as a result of ion exchange is absorbed by strong basic anion exchanging resin stored inside the next vessel. Standard of these plants has been verified on the basis of their service life, production rate, mode of operation and operating cost.