Reverse osmosis (RO) water systems are designed to remove a large number of impurities in tap water but offer lower levels of purity than other grades of water. However, RO water (Type III) is often used in media preparation, glassware washing, and other non-critical roles in the laboratory, as well as being the preferred feed method for a Type I or Type II water system.
The size of the unit can vary based on the applications and throughput the system is being used for you with larger labs and manufacturing processes requiring systems with larger volume capacity and even the use of a reservoir.