What has been newly created is an apparatus that minimizes usage of the clean drinking water that has been hauled from a distant river/source, and maximizes usage of a low-grade water, such as subterranean water, sea water, recycled water and rain water for low-grade functions, such as toilets, firefighting, irrigation, etc, that are readily available near/within habitation communities that are totally dependent upon a public water,—in the form of an assembly of pipelines for low-grade water supply into the toilets of facilities/buildings/houses that is made separate and distinct from the usual clean drinking water pipeline in the house, wherein, a water deep-well is constructed under or within the yard of the houses/buildings or facilities/parks serving a water source for the low-grade pipelines, wherein, the low-grade pipeline is also connected to a municipal recycled water,—in order to prevent the clean drinking water from getting into the toilets, wherein, low pressure low-grade water tanks are installed in every floor level of the buildings to save energy spent for pumping, and wherein further, a municipal or national law is enacted to enforce under penalty the construction of water deep-wells for every building/facility and to enforce maximum usage of low-grade water.