The vast majority of industrial cleaning processes today use water-based chemistry for cleaning and the cleanest water possible for rinsing. Most water comes from wells or reservoirs and arrives via a municipal utility which may filter it and add chemicals to kill and prevent the growth of bacteria and/or provide certain health benefits. Other than that, little is done in most cases to standardize water. We, in fact, are accustomed to the fact that water from a tap in one city may taste totally different that in another city – usually due to differences in mineral content. Variations in “water” that are totally inconsequential in domestic use, however, may have a major impact in industrial cleaning applications. The water in a given geographical area is a product of its environment since, basically, it all comes to us via open contact with the local geological strata. Along the way, it accumulates particles of various sizes and descriptions as well as whatever it can dissolve (remember, water is often called the “universal solvent” and for good reason). Some particles are removed by the supplying utility through the use of filtration prior to distribution. Additional particles, however, are often accumulated as the water travels through underground pipes to the point of delivery. Although filtration to remove particles and sediment are common, utilities seldom make any effort to remove dissolved gasses and solids from a water supply. Even domestic users often install water “softeners” and such things as activated carbon filters to remove impurities that may result in unpleasant tastes and odors as well as leave “soap scum” and unsightly mineral deposits on plumbing fixtures. These measures, although effective and adequate for water for domestic use frequently fall way short of the needs for most industrial cleaning. Almost invariably, water for industrial cleaning applications requires a certain degree of treatment prior to use. The degree of treatment varies depending on the locality. It is important for the user to know as much as possible about the water being supplied by the local utility. In most cases this information is available for the asking and should be provided to cleaning chemical and equipment suppliers during the process development phase of a project. Understanding variations in local water supplies should also be a major consideration when moving a cleaning operation from one location to another or attempting to duplicate a cleaning process in another location. Once the properties of the incoming water supply are understood, treatment solutions to provide water adequate for the process are relatively straight-forward. There is, however, no universal treatment that will be adequate in all situations. Water and water quality is an important and complex issue which requires attention in nearly every industrial cleaning process. The above merely sets the stage for much more involved discussions. In upcoming posts we will explore water in more detail talking about resistivity, conductivity, dissolved solids, reverse osmosis, de-ionization, distillation etc. and the importance of these and other issues in industrial cleaning. There is more to water than meets the eye so stay tuned!