Rising energy costs, declining groundwater supplies, increasing competition for water resources between agricultural, industrial and domestic users and irrigation-induced water quality problems are providing considerable impetus to improving efficiency in irrigated agriculture. Much of the groundwater used for irrigation is found in closed underground basins. Water percolation is the only source of water available for recharge. In some basins, the pumping rate is much greater than the recharge from percolation and ‘water mining’ occurs. The aim of this study was to compare the yield components and quality factors of sweet corn grown under different irrigation scheduling strategies. The treatment with 426 mm of seasonal irrigation offered the largest commercial yields, with an appropriate quality production, good irrigation efficiency, the highest gross margin and the best break-even point irrigation strategy. Treatments with higher application produced lower irrigation efficiencies.