The aim of this experiment was to quantify the water hardness from three different sources: the Red River, tap water, and drinking fountain water. The procedure for determining the concentration of calcium and magnesium from a water sample using AA was taken from the Environmental Protection Agency.4,5 It was expected that the hardness of the Red River should be significantly higher than the others as it was untreated. However, the recent flood of the Red River has raised concern about an increased mineral concentration in the river, as well as in the tap and drinking water. A comparison of water hardness now versus the pre-flood environment will provide useful information about the nature of flooding. The difference between the tap water and the drinking fountain water hardness was also examined to determine whether or not they come from the same source and if the drinking fountain water is softened more than the tap water. Moreover, the calibration curves from the software are often assumed to give accurate results without testing. In response the accuracy of the calibration curves generated by the Varian software was investigated by plotting the same curve in Microsoft Excel and generating a curve-of-best-fit.