In many parts of the world, cities dump untreated human wastes, along with industrial and agricultural wastes, into the same rivers or lakes, from which other cities (or other neighborhoods of the same city) extract their water supply. Preserving sources of safe water supply, in the face of rapid urban growth, requires advance planning -often on a regional basis - plus enforcement of watershed protection measures and application of urban growth restrictions. Industries with toxic effluents, or high-density residential developments with untreated wastes, need to be steered away from water sources or areas that will need to be drawn upon as water sources in the future. Economic incentives or regulations can be set up to accomplish this dealing with aging distribution systems imposes high economic costs for resource-strapped urban water and sanitation service (WSS) providers. It is not rare for 40% or more of all water that enters the distribution system to be unaccounted for through theft, illegal hook-ups, abuses of the right to free water, and, most importantly, leakage, either through public mains or household connections.