Some people can effectively use a dowsing rod to find water; that is a gift. Most of the time, however, water superintendents must rely upon some form of electronic leak detection device that either uses sound or a metering apparatus to locate leaks in valves, hydrants or pipelines.
Pipe and cable locators are used to trace water or cable lines and measure the underground depth of pipe and cable by electronic means, through either conductive (hooked to service) or inductive (no direct connection) analysis. This saves costly digging and needless damage. Magnetic locators help the searcher find valve and service boxes and other ferrous objects that are close to the road surface. These locators may be sensitive electronic listening devices or simple box locators.
The value of a locator is measured by the time and effort it saves.