District Metered Areas (DMA) are sections of a water distribution system that are isolated from the rest of the system (usually with closed valves) such that all of the water in and out of the DMA can be metered. DMAs provide a means of more accurately tracking water use and loss than in a system without DMAs.

Creating DMAs involves identifying areas in a distribution system that can be isolated and metered without negatively impacting service. This can be difficult, especially in highly looped systems where DMA creation could involve closing a large number of valves. It is important to model system performance with and without DMAs to ensure that DMA creation will not adversely affect pressure and fire flow.

WaterGEMS/WaterCAD DMA tool can greatly assist the user in identifying candidate DMAs based on user supplied criteria. The tool will suggest which boundary elements (pipes/pumps/valves) should be closed to isolate a DMA. It is up to the user to determine which of those boundary links will be closed or become flow meters. It is expected that the user will incorporate an iterative process to manually adjust the DMA choices suggested by the DMA algorithm. The engineer will want to review the various attributes of the resulting DMAs and should additionally verify the hydraulic system performance to assess considerations not accounted for in the algorithm (e.g. convenient location of meter vault).