A fire department connection (FDC) enables the fire service to connect hose lines from one or more pumpers and feed water into a system to augment its automatic water supply. Systems include sprinkler systems, standpipe systems, or other water-based suppression systems. Each fire department connection has one or more fire hose inlets. In manual dry standpipe systems, FDCs are the only water supply.

The requirement to provide an FDC typically appears in the installation standard for the corresponding type of system.

Each fire department connection (FDC) shall be identified by a permanent weather resistant sign. When the system supplied by the fire department connection does not supply the entire building or supplies multiple buildings, signs shall identify the building areas of the building supplies by the FDC. The fire department connection sign shall identify the building address or area, where necessary, and type of system the FDC supplies.