A device for reusing greywater includes: a water feed for supplying greywater; a collecting reservoir for collecting the supplied greywater; a storage tank for storing water; a siphoning device for siphoning water from the collecting reservoir to the storage tank; a water discharge for discharging stored water to a water user; a sewer outlet; and a control system. A method of siphoning water includes: supplying water to a collecting reservoir; detecting a predetermined water level in the collecting reservoir; operating a filling valve subject to the detected water level; and siphoning water via a siphon connection from the collecting reservoir to the storage tank.