Drainage watrer quality and quantity and crop yield in a 22 ha field were measured since 1986. The field was in a corn-soybean rotation with N-fertilizer applied to the corn in spring. The data showed that even at the low N-fertilizer rate, nitrate-N concentrations were greater than the maximum contamination level (MCL) for drinking water in corn years and in all years for the M (9.81b Mg ha-1) and H (9.78b Mg ha-1) N-fertilzer treatments. Optium corn yields occurred between the l and M treatment in 1996 abd the M and H treatment in 1998. Therefore, maximum corn yield cannot be sustained in this particular field without producing drainage water that exceeds th MCL standrad set out by the EPA.