Disclosed is a filter system with at least one filter element (1) that is arranged below the surface of a body of water, with a fluid to be cleaned t hat can flow from the inner fluid chamber (11) of the filter element to the exterior of the latter, and that is surrounded by the body of water on the e xterior such that the cleaned fluid can be discharged into said water. The f ilter element (1) has a column-like shape defining a vertical axis and is im mersed in the body of water with the vertical axis running essentially verti cal. The exterior of the filter element is surrounded by a sheath (25) that forms a flow canal (29) for a vertical flow of the body of water between sai d sheath and the exterior of the filter element (1).
