This study was performed for the Rural Electrification Board of Bangladesh. It was funded by the United States Agency of International Development (contract number US AID RE III 388-0070). The contract was implemented by National Rural Electric Cooperative Association (NRECA) International, Ltd. of Arlington, Virginia with personnel from The Johnson Company, Inc. of Montpelier, Vermont, USA and the Environmental Health Program of the International Center for Diarrhoeal Disease Research, Bangladesh. The project team offers our sincere thanks to Mr. James Ford of NRECA for providing invaluable leadership and management during the implementation of this ambitious contract. The principal investigators offer our deepest thanks to the dozens of talented and motivated Bengali scientists, engineers, and support staff who made this work a reality - the future of Bangladesh and West Bengal is bright indeed.