Provided are a turbine facility and a water treatment method for heater drainage water in the turbine facility, with which iron oxide particle scale that adheres to the inner surface of boiler pipes and impedes the transfer of heat can be efficiently removed from the heater drainage water. The present invention has: a boiler (9); steam turbines (12, 16); a condenser (1); water supply heaters (5, 8), which are interposed in water supply lines (4, 6) that supply the condensate condensed by the condenser (1) to the boiler (9), and which extract as bleed air a portion of the steam supplied from the steam turbine (12) to a reheater, and use this to heat the aforementioned supplied water; and a filter device (19) that recovers water by filtering the heater drainage water discharged from the low-pressure water supply heater (5) and sending the water to the aforementioned supply lines. The filter device (19) has a filter with a hole diameter of 1-5 mum.