A Single Detector Check Valve backflow prevention device can be used in Victoria to provide low hazard protection for building fire water services, it incorporated a backflow protected metered bypass to detect leaks and illegal unmetered water use at low flow rates. Low flow rates will occur at any time other than when testing, flushing or using a fire hydrant. Single Detector Check valves are containment devices and require annual testing and certification to satisfy the requirements of the local water authority.