A hybrid fire suppression system includes a supply of pressurized inert gas, a pipe network connected in inert gas flow communication to the inert gas supply, a first inert gas nozzle, a second inert gas nozzle, and a water storage cartridge having an interior volume defining a water reservoir storing a limited amount of water. The water reservoir communicates with the second inert gas spray nozzle. The first inert gas nozzle connects with the first terminus for introducing a flooding flow of inert gas only into a first protected space. The second inert gas nozzle connects with the second terminus for introducing a flooding flow of inert gas and the limited amount of water from the water reservoir into the second protected space.