The invention relates to a separating device (1) for fluid-collecting sumps, in particular of filter or water separators, comprising a line pipe (10) which has a connection opening (11) and an outlet opening (12), wherein the line pipe (10) is equipped with a flow restrictor (20), a phase detection sensor (30) for detecting a phase boundary (G) between a light fluid (F1) and a heavy fluid (F2), and an electronically actuatable outlet valve (40) between the phase detection sensor (30) and the outlet opening (12). The outlet valve (40) is actuated by a regulating device (45) such that the outlet valve (40) is brought from an open position into a closed position when a phase boundary (G) is detected by the phase detection sensor (30). The invention additionally relates to fluid container devices (100) comprising a fluid-collecting sump (101) and such a separating device (1).