The use of urban wastewater in agriculture is a common practice for diverse reasons, not least of which are water scarcity, fertiliser value, and lack of an alternative source of water. It is necessary to have a clear understanding of wastewater's importance and significance in terms of extent, agricultural production, and livelihood impacts before appropriate policies, strategies and guidelines for its use in an integrated water management framework are developed. The Vietnam nationwide assessment was the pioneer in a series of such assessments being undertaken by the International Water Management Institute (IWMI). Findings indicate that 75% of domestic wastewater in large cities and 45% in smaller cities are discharged into sewers. Wastewater is used for agriculture or aquaculture in 93% of the cities. On an average wastewater is used in at least 2% of the agricultural land around most cities, predominantly to grow rice. The nationwide total of such irrigation is conservatively estimated at around 9,000 ha. Wastewater aquaculture is carried out in natural ponds which serve the dual purpose of inundation control and as collection sinks for city wastewater. Wastewater agriculture provides a primary or secondary source of income to 1% of the urban population. The corresponding figure for wastewater aquaculture is 0.1%. Factors that influence the use of wastewater in non water-short regions have emerged, showing a possible pattern of wastewater use under these conditions. A key result from this study is the need for a typology that effectively captures all these characteristics, as a prerequisite for a global assessment.

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