Clivus Multrum. The Clivus Greywater System includes a Greywater Dosing Basin as the collection point for all of a home’s greywater. Made of rigid plastic, it contains level switches and an effluent pump or gravity siphon (where sufficient slope is available). When an amount of greywater sufficient to create a 11/2-inch flooding dose within the irrigation chamber has collected in the dosing basin, the pump (or gravity siphon) engages. Because the irrigation chamber is flooded throughout its length, water and nutrients are carried evenly to surrounding plants. 800.425.4887.