Water pollution problems in Latin America and the Caribbean became evident during the 1970s. Most pollution was caused by agriculture and the discharge of untreated urban and industrial sewage. Control of water pollution has reached primary importance in developed and many developing countries. The urbanization process changes the landscape and the flows of materials and energy in urban areas. Changes in the landscape and transport of runoff are particularly important with respect to surface runoff and its characteristics. The treatment of wastewater and its use and/or disposal in the humid regions of high-income countries are motivated by stringent effluent discharge regulations and public awareness about environmental quality. Micropollutants include organic or inorganic substances with persistent, bio-accumulative and toxic properties, which may have adverse effects on human health or/and biota. Integrated water resources management is a systematic process for the sustainable development, allocation and monitoring of water resource use in the context of social, economic and environmental objectives.