Filter device for the treatment of water, of the type submerged membrane including means backflow of the medium to be filtered to the means for injecting declogging gas.

The invention relates to a filter device with at least one membrane (13) intended to equip a water treatment facility of the type immersed in a medium to be filtered and comprising injection means a gaseous fluid in the form of bubbles for the declogging of said one or membranes, characterized in that it comprises anti-backflow means to prevent contact of said medium to be filtered with said injection means.