Abstract: Subject-matter of the invention is a modular distribution head for a membrane housing body including a front side, a pipe connection to the membrane housing body, a gasket to seal the membrane housing body which is placed in the pipe connection, at least two flow openings in the distribution head through which the liquid can flow in and out of the distribution head and the membrane housing body whilst the flow opening is e.g. a liquid inlet, a permeate outlet or a concentrate outlet. The use of the distribution head or plant as per the invention leads to a considerable reduction in space required. In addition to less required space, a further advantage of the distribution heads as per the invention is that the connector pieces and the hydraulic connections are no longer necessary since the distribution heads are directly connected to each other and less collector pipes are needed in a plant.