Nutrients in wastewaters from some municipal sewage treatment plants and intensive rural industries have contributed to water quality problems in Australian rivers and estuaries. Concern over toxic algae and eutrophication has accelerated the trend from direct disposal of wastewaters into water bodies to disposal onto land. The underlying principle is to allow pastures, crops or trees to consume the nutrients and water. In theory, this turns a problem into a commercial opportunity. However, wastewater irrigation must be appropriately sited, well-designed, and well-managed, if we are not to trade a surface water problem for a groundwater problem. This paper describes current practices and guidelines (and a weakness they have in common) and a proposed approach to groundwater quality protection for wastewater irrigation sites.