We propose a unit structure based on a water core with a skeleton attatched to it. Residents build theire own units within the skeleton. Rain water is collected on the roofs of the units, and stored in a watertank within the core. This water is used for kitchen and toilets in every unit, and the greywater is filtered and sent back into the ground. A typical unit consists of 4*4meters floor area on 4 levels. The ground floor is free and open for temporal programs when the area is not flooded.