To protect MWRD customers, the department requires backflow prevention protection at any connection to the potable water supply that might allow contaminants to flow backwards into the system. This means that all commercial and industrial customers are required to have an approved device in place between their facilities and the city water supply. In addition, all underground irrigation systems are required to have such devices.
These devices are inspected by MWRD personnel on a regular basis. Because most of middle Tennessee is underlain by fissured limestone, many of the wells in this region periodically suffer contamination from surface runoff. The Murfreesboro City Code prohibits interconnections between wells and the city water supply.