A survey of existing literature and interviews with 25 development practitioners provide the basis for this report on the health effects of pesticides in water used for drinking and for irrigation in developing countries. Individual chapters of the report: (1) identify the organic compounds found in water, with an emphasis on non-pesticide organic compounds found in developing country waters; (2) describe the present and projected extent of pesticide use in developing countries, along with pesticide contamination of water and resulting health effects/risks; (3) identify water-related infectious diseases and ways of treating or preventing them; and (4) discuss the health effects of the existence in water of inorganic compounds, solid particulates in suspension, and radionuclides. Recommendations focus on avoiding or reducing pesticide (and fertilizer) contamination of irrigation water and on treating such water to remove pesticides. Appendices provide a discussion of toxicology, 6 technical tables, and a 9-page bibliography (1953-81).